From akestelo at bellatlantic.net Mon Jan 1 08:42:54 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:18 2003 Subject: [Lf] More on helium baloons Message-ID: <3A50895D.A1878CB2@bellatlantic.net> Steve Rawlings wrote: > Hi All, > > I managed to get four helium-filled balloons flying from 14:30 > yesterday (30/12/2000) at a height of 27 metres. Occasionally > the breeze came up, so down came the balloons. But, overall, > conditions were sufficiently calm to work three new stations (all > greater than 800 km), including a new 'first' from GW. > > First in the log were G6NB (good to hear you again, Bill) and > G6RO. Then the arrival of a gentle breeze meant that I had to > haul in the balloons. > > In the early evening, I worked: > M0BMU - a big signal, Jim > F6CNI - glad that we finally made another QSO, after many months > DJ8WX - our first QSO, 860 km > OZ1KMR - the first GW-OZ on 136 kHz, 896 km > > At about 19:30 the air became very still. What a lovely sight to > see the balloons: now exactly above the anchor point. Very > rarely do we get the kind of weather conditions that enable me to > get the balloons up to 27 m - perhaps only 2 or 3 times each > year. So I was set for an 'all nighter': a flask of coffee at > the ready. > > During the evening I worked: > G6RO - good signals from Ron's new antenna > DK8KW - Geri! Nice to hear you again. AWDH > DL3FDO - Very nice to work you Reiner, after a few 'near misses' > in the past. 828 km. > > Up until 22:00, things had been going very well - and the antenna > wire was still vertical over the anchor point. > > As many of the the stations worked were using 136.5 +/- 200 Hz, > you can imagine my disappointment when QRM from the intermittent > carrier appeared on 136.5, with strong sidebands +/- 100 Hz > (already mentioned in other postings to this reflector). I did > try for further contacts: I stuck it out for a couple of hours, > but everyone else had given up - so I went to bed too. A > disappointing end to an otherwise successful day. > > Today (Sunday), the weather is back to being wet and windy. So > conditions are back to 'near normal' (for Wales!). > > A Happy New Year to all, > Steve GW4ALG From akestelo at bellatlantic.net Mon Jan 1 08:41:32 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:18 2003 Subject: [Lf] [Fwd: LF: Slow Voice Experiments] Message-ID: <3A50890B.3604A47B@bellatlantic.net> "'Geri' Kinzel, DK8KW" wrote: > Hello LF Enthusuasts, > > after Markus' succesful one-way slow-voice transmission on LF we will try > to conduct a two-way QSO in this mode today. > > I will use the follosing parameters: > > The audio frequency range between 300 Hz and 2300 Hz is reduced in speed by > 8 times. The transmission spectrum after the conversion will be transmitted > between 137.350 kHz and 137.600 kHz USB (250 Hz wide, so a narrow CW-filter > can be used), so that 137.350 kHz corresponds to the 300 Hz audio frequency > and 137.600 kHz corresponds to 2300 Hz audio. > > For demodulation with an audio mixing software (e.g. Cool Edit, Goldwave, > etc.) two steps are necessary: first, the recording has to be speeded up by > 8 times to re-gain the original audio bandwidth, second the audio signal > has to be shifted by a certain fixed frequency to get the audio passband > back to the original position. This can be done for example in Cool Edit > using the "generate", "tone" menue and the "modulate" option, which > simulates a ring modulator mixing with the generated frequency. After the > ring modulation two sidebands are generated, so that one needs to be > filtered out. > > Walter, DJ2LF, has successfully used another method to shift the audio > frequency. He fed the audio signal into an SSB transceiver and could change > the pitch by changing the receive frequency. > > Markus and I will meet today, Sunday, December 31st, 2000 at 09.00 UTC on > 137.500 kHz in PSK31 to arrange the voice transmissions. In between the > voice transmissions we will use CW on 137.475 kHz top arrange beginning and > ending of the voice transmissions. In between the transmissions there will > be a gap in which we will try to demodulate (and understand -hi-) the > transmitted signal. > > If you hear any spurious signals outside of the announced band (137.350 to > 137.600 kHz), please let me know. I am using a 135.500 kHz exciter signal > fed by an audio frequency signal between 1850 and 2100 Hz to generate the > LF signal and I will try to keep my transmission as clean as possible. > > Best 73 > > Geri, DK8KW (W1KW) From akestelo at bellatlantic.net Mon Jan 1 08:47:42 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:19 2003 Subject: [Lf] First 2-way Slow-Voce QSO ...slow voice software....where?] Message-ID: <3A508A7D.8298E803@bellatlantic.net> "'Geri' Kinzel, DK8KW" wrote: > Hello David and LF-group, > > >where might this software be? > no lf in usa, but 160m can be a bear too ! > david< > > today, Markus, DF6NM and I have performed the first succesful 2-way LF QSO > in slow-voice. Markus used a software named Goldwave (don't know where that > can be found but Markus said it is shareware, so have a look in the > Internet search machines ...). I used Cool Edit 2000, that can be > downloaded at http://www.syntrillium.com (it is also shareware, the demo > version comes with two functions only, you need to register to have full > access to all features). > > We started at 137.350 to 137.600, where Markus was able to read my signal > (8 times slower than normal voice) with 57. When I tried to receive him I > found that the 1.7 kHz filter that I use in my MV62 Level Meter was too > wide to prevent DCF39 from causing heavy QRM. The build-in 100 Hz filter is > too narrow for the 250 Hz bandwidth we used. The 250 Hz filter that I use > in the IC-746 that comes behind the level meter on 200 kHz is narrow > enough, but it comes too late, the band is already spoiled by the Burg > transmitter. > > The solution was to move 500 Hz further down, with our transmission > spectrum situated between 136.850 and 137.100 kHz. I hope we did not cause > any inconvenience to anyone tranmitting there. We have accompagnied our > slow-voice transmissions with CW to steer the QSO. All in all it took about > 2 1/2 hours to complete the QSO, whereby my report for Markus was 35, > however, in a later transmission I could read him better than that > (probably 45). > > The QSO mainly too that long because I had to fiddle around with the > appropriate adjustments. For the transmission I used macros, so it took > only one or two minutes to be able to transmit a 3 minute over. For > reception I did not prepare anything and had to do some experimentation. > > For future transmissions we will need to find another way or a better clear > spot, maybe even further reducing the bandwidt to 100 Hz and make use of > the narrow filter ... > > I know that SSB QSOs have been performed in the band some years ago in the > U.K., but this slow-voice transmission helps us to > > - overcome the bandwidth limitation in Germany (max. 800 Hz) > - helps to prevent QRM aking best use of the availabel spectrum > - increases the signal-to-noise ratio relative to the bandwidth used > - ... and is a lot of fun ... hearing the other's voice clearly readibly > despite the low signal strength! > > I will post some further information on my website (http://www.qru.de). > > So, a new field of experimentation. We will conduct further tests and > improve the operating procedures. Maybe someone who has fun programming the > Soundblaster card might want to develop a slow-voice software that allows > more-or-less realtime QSOs ... > > Best 73, thanks to Markus, DF6NM for the nice experience, to Walter, DJ2LF > for his reception report and a very happy New Year 2001 to you all! > > Geri, DK8KW (W1KW) > > > Slow-Voice data of the QSO today (December 31, 2000): > > - transmitted audio bandwidth 300-2300 Hz (2000 Hz total bandwidth) > - speed: 8 times slower than the normal voice > - transmition mode: USB > - total radio frequency bandwidth 250 Hz with 300 Hz audio equal to the > lower frequency of the spectrum, 2300 Hz to the upper freqeuncy > - QSO control by CW in the middle of the spectrum used > > From akestelo at bellatlantic.net Mon Jan 1 20:15:58 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:19 2003 Subject: [Lf] Al Gross W8PAL, sk Message-ID: <3A512BCD.3703527C@bellatlantic.net> Thanks to Mark, N4TPY for bringing this to my attention. Andre' N4ICK **************************************** Friday December 29 01:15 PM EST Passing of a wireless pioneer By David Coursey, ZDNet News Remembering a forgotten wireless pioneer. "The man who brought the world such indispensable wireless communications concepts and devices as the walkie-talkie, pager, and cordless telephone has died." That's the lead sentence of an email I just received from a ham radio news service I subscribe to. The story is so interesting and the accomplishment so great that I'd like to share it with you. First, though, I'll need to shut off the cordless phone, put the pager in silent mode, and turn down the volume on the walkie-talkie I use in my volunteer work. It is startling to realize how much I owe to the inventions of a guy I didn't even know about. And now he's dead. His name was Al Gross. His ham radio call sign was W8PAL, and he died four days before Christmas at his home in Sun City, Ariz. Here's the rest of the email: "Gross obtained his amateur radio license in 1934 at the age of 16. His early interest in amateur radio helped set his career choice while he was still a teenager. "Gross pioneered the development of devices that operated in the relatively unexplored VHF and UHF spectrum above 100MHz. His first invention was a portable hand-held radio transmitter-receiver. "Developed in 1938 while he was still in high school in Cleveland, he christened it the 'walkie-talkie.' The device caught the attention of the US Office of Strategic Services -- the forerunner of the Central Intelligence Agency. The OSS recruited Gross, and this led to the invention of a two-way air-to-ground communications syste m used by the military behind enemy lines during the World War II. The system allowed OSS agents to communicate with high-flying aircraft. "After World War II, Gross set up Gross Electronics Inc to design and build various communications products, some of them under government contracts. He also launched Citizens Radio Corporation to design, develop and manufacture personal wireless transceivers. "Cartoonist Chester Gould asked if he could use Gross' concept of a miniaturized two-way radio in his Dick Tracy comic strip. The result was the Dick Tracy two-way wrist radio. "During the 1950s and 1960s, Gross secured several patents for various portable and cordless telephone devices. In September 1958, Gross Electronics received FCC type approval for mobile and handheld transceivers for use on the new Class D 27-MHz Citizens Band. "'If you have a cordless telephone or a cellular telephone or a walkie talkie or beeper, you've got one of my patents,'Gross once said. He added! ! that if his patents on those te chnologies hadn't run out in 1971, he'd have been a millionaire several times over. "Over the years, Gross worked as a communications specialist for several large companies. Since 1990, he had worked as a senior engineer for Orbital Sciences Corporation (NYSE:ORB - news) and was still on the payroll there when he died. "Gross received numerous awards and honors during his distinguished career, including the 1992 Fred B. Link Award from the Radio Club of America, the 1997 Marconi Memorial Gold Medal of Achievement from the Veteran Wireless Operators Association, and the 1999 Edwin Howard Armstrong Achievement Award from the Institute of Electrical and Electronics Engineers. In 1998, he received Eta Kappa Nu's Vladimir Karapetoff Eminent Members' Award in recognition of his pioneering contributions to the engineering of personal wireless communications. "Earlier this year, he won the Lemelson-MIT Lifetime Achie vement Award for invention and innovation and for playing a major role in the wireless personal communications field." As his IEEE biography put it: "It is clear that Mr. Gross was a true pioneer and helped lead the way to today's wireless personal communications revolution." Gross was, of course, only one of many communications pioneers. Yet his accomplishments are all around us. Someday our children will be startled to learn of the deaths of some Internet pioneer or maybe someone from Xerox PARC--an Al Gross of our age. (Thanks to the ARRL, the W5YI Report and the IEEE, all of whom contributed to the email quoted in this column.) ZDNet News commentator David Coursey is based in Silicon Valley and has covered personal computers, software, and the Internet for more than 20 years. He is an industry analyst and creator of several industry conference events. His Web site is www.coursey.com. From akestelo at bellatlantic.net Tue Jan 2 09:32:29 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:20 2003 Subject: [Lf] QRM on 136.500] Message-ID: <3A51E67C.48B76C50@bellatlantic.net> "mike.dennison" wrote: > > The balloons here at GW4ALG are flying well and the local noise > > level is dropping . . . > > But a strong intermittent carrier is clobbering 136.5 kHz, the > > most commonly-used frequency for normal CW operation. > > There is a worrying trend to use 136.5kHz for transatlantic transmissions. I > understand that VE1ZZ is crystal controlled, so he can be forgiven. However, > I have heard both QRSS and conventional CW transmissions from G stations on > this frequency aiming to be heard in VE. > > Two problems are raised here: one is mentioned by Steve above, and the other > is that co-channel operation is extremely inefficient for this type of > marginal contact. > > It was not long ago that sub-bands were proposed for Eu-NA (low end of band) > and NA-Eu (high end of band). I have the details of this on my web site and > requests for comments produced no result so I assume they are still > accepted. > > Is there now (1) a wish for a free-for-all, or (2) a wish for new sub-bands? > > I, for one, am very confused. Where should I transmit and receive now? > > Mike, G3XDV > www.lf.thersgb.net From akestelo at bellatlantic.net Tue Jan 2 09:31:26 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:20 2003 Subject: [Lf] First 2-way Slow-Voce QSO ...] Message-ID: <3A51E63D.2206C274@bellatlantic.net> "'Geri' Kinzel, DK8KW" wrote: > Hello and a Happy New Year to all of you! > > I have posted some further information on Marus' (DF6NM) and my 1st > Slow-Voice QSO on LF on my homepage > > http://www.qru.de/slowvoice.html > (also: http://home.t-online.de/home/dk8kw/slowvoice.html) > > where you also will find MP3 sound samples of the voices as they were > received after compression to 250 Hz bandwidth and decompression on the > receiving side. > > A really interesting way of communication and an exciting field for further > experiments! > > Best 73 > > Geri, DK8KW (W1KW) From akestelo at bellatlantic.net Tue Jan 2 14:28:28 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:20 2003 Subject: [Lf] matchingtransformer Message-ID: <3A522BDC.863E24A7@bellatlantic.net> Steve Rawlings wrote: > Hi Uwe! > > ... got a letter from Wil/PA0BWL containing his wiring diagram > > of his antenna-matching. there is a blackbox in it he named > > "transformer-GW4ALG-type" . . . would you be so kind giving > > the diagram/the details of that "blackbox"? > > I am sure that Wil will be answering your letter soon. Meanwhile > those interested can find details of my antenna matching > transformer at: > http://www.alg.demon.co.uk/radio/136/ant_xformer.htm > > Regards to all, > Steve GW4ALG From akestelo at bellatlantic.net Tue Jan 2 14:30:14 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:20 2003 Subject: [Lf] hamscope for free ? Message-ID: <3A522C46.4DE08578@bellatlantic.net> Peter Martinez wrote: > >From Peter G3PLX > > I don't know exactly who wrote Hamscope, since the two recent > announcements about it are from two different people, but if it is > using the PSK31 kernel by Moe Wheatley, which is based on my original > source code, then there should have been an agreement by which the > author undertook to make derived software available free, since this > condition was imposed by me on everyone who received copies of my > original source code. The only exceptions I made were where an > author wished to add PSK31, using my code, to a program which he was > ALREADY selling for a price. In this case I required that the price > was not hiked as a result of the added PSK31 feature. Hamscope > appears to be new and therefore doesn't come into this category. It > should be free. > > I sincerely hope that the author, whoever he is, will remove the > registration fee. > > 73 > Peter > _______________________________________________ > Psk31 WWW Site at http://aintel.bi.ehu.es/psk31.html > Psk31 list info at: http://aintel.bi.ehu.es/mailman/listinfo/psk31 From akestelo at bellatlantic.net Tue Jan 2 14:30:55 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:21 2003 Subject: [Lf] Hamscope 1.2 Reviewed] Message-ID: <3A522C6F.10C918F1@bellatlantic.net> "Andrew J. O'Brien" wrote: > Hamscope 1.2 Reviewed > By Andy KB2EOQ > (this review may be distributed without restriction) > > Well, with the CCCC Millennium Multi Digital Mode contest taking place New > Years Day , what better way to test out KD5HIO's Hamscope. Hamscope, > available at http://users.mesatop.com/~ghansen/ , is the latest entry into > the vibrant Windows based ,soundcard driven , digital radio world. As the > most recent entry , the author has found time to incorporate many varying > digital modes all into one software package. Most digital software these > days includes PSK31 and RTTY (TrueTTY, Zakanaka, et al) but Hamscope is only > rivaled by MixW in the choice of modes that one can select. > > Available modes are > > BPSK31 > QPSK31 > RTTY > ASCII7 > ASCII8 > MFSK16 > HFSK16 > CW > > Missing are the increasingly popular Throb, the much advocated MTTY, ye olde > PACKET, MT63, PACTOR, CLOVER, and the altered versions of PSK and MFSK > (PSK63/125 and MFSK8/4). However, Hamscope is a very full featured program > and a welcome addition to the digital ham's repertoire. > > Installing Hamscope > > Hamscope installed on my AMD K2 500 PC with 64 megs of memory without any > problems. Within seconds of executing the install program, I had a very > carefully thought out screen displaying RTTY, PSK31, and MFSK without any > problems. The macros are nicely laid out and easy to edit. They are > essentially the same in appearance to those in Digipan. You have 36 macros > to choose from but . unlike Zakanaka, not all can be displayed at the same > time. Hamscope, like Digipan, requires that you click an arrow to see the > next bank of macros. > > As mentioned earlier, MixW is the only program that has as many modes as > Hamscope. However Hamscope is vastly superior to MixW in terms of > appearance and the general feel of the program. MixW generally performs > well (although RTTY is mediocre) but it's help files are very disjointed and > have caused many a ham to feel frustrated. Hamscope on the other hand, is > most pleasing to the eye, and the intuitive computer user will find > themselves operating the digital world with hardly any need to consult the > help files. > > Okay, so how well does it perform? I tried CW, MFSK, BPSK31, and RTTY and > had generally positive results. > > CW works well and I could see no appreciable difference between MixW and > Hamscope's ability to copy CW. My unscientific tests indicate the CWGet out > performs Hamscope and MixW in weak CW conditions, but no software copies > weak signal CW very well. . Hamscope nicely displays both the transmitted > CW speed as well as the receive speed. I have sometimes found that CW > copying software has difficulty with high speed CW but Hamscope copied > KM5HT's 40 WPM code without problems. Copying CW was as simple as clicking > on the vertical trail in the waterfall or on the spectrum display. The > word length , dash length and noise threshold can all be easily changed in > Hamscope's set-up area. I did note that there is a noticeable delay from > when your brain hears a CW character to when it actually is printed on the > screen. At average speed CW, the printed text is usually a character behind > what has actually been sent. While this may seem understandable in that the > computer has to process the received signal, it appears more noticeable on > Hamscope that other CW packages. > > MFSK16: I really like Hamscope's MFSK. I have been a STREAM users since > MFSK's birth but have found the horizontal waterfall in Stream difficult to > get comfortable with. It is no doubt psychological, but I found that > Hamscope's vertical waterfall for MFSK very easy to handle. The AFC does a > good job of locking on to a MFSK16 signal , although it does so rather > slowly...you can see it edging up the band like someone doing the > breaststroke. Missing are the Clock Alignment , Bit Shape, and Phase Scope > display that Stream provides . I was unable to determine any performance > difference with Hamscope of Stream, both had the same copying abilities , > but Hamscope's waterfall had me tuning them in quicker. > > PSK31: AE4JY's core is used for PSK31 just like it appears to be in every > other PSk31 program these days. Hence the basic PSK31 performance should be > the same. The AFC was again a little jerky but it did its job well by > locking on to PSK31 signals that were nearby. If between two signals, one > strong and one weak, the AFC sought out the stronger one each time. There > is no tuning or phase scope like the ones you can find in Zakanaka or > PSK31SBW, I still find such tuning aides useful. As far as I can determine > there is no ability to copy more that one PSk31 signal simultaneously, > Digipan, WinWarbler, Zakanaka and other all have multi-receive capability. > Hamscope also lacks some of the bells and whistles that Digipan has (search > feature) and also lacks some of the fancy tricks that Zakanaka's macros can > perform (rig QSY, passband centering. logging inserts and more). Overall it > performed well. > > RTTY: This the mode that I had the most difficulty with. The first thing I > noticed was that it appears to default to a setting that requires RTTY to be > tuned in USB if you want to be able to copy signals. . Hamscope displayed > the RTTY signal very nicely on the spectral or waterfall displays and the > AFC appears to track nicely, but I had problems copying even quite strong > signals. There is no tuning scope like that in MMTTY or Zakanaka. One S3 > signal on 10 meters would not display any intelligible signals at all but a > quick flip to Zakanaka with MMTTY's RTTY engine and I was copying the same > signal,an HB9 station, CQing with 100% copy. Hamscope provides the RTTY > user with a couple of FEC possibilities but I did not attempt to use these > features. It certainly does not have the advanced filtering capabilities > that MMTTY and Zakanaka provides the RTTY users. I don't anticipate any > RITTY users giving up that DOS based program for this either. Perhaps I > chose a bad day, the HF bands were down quite a bit but Hamscope's weak > signal RTTY was way below the competition. > > Logging: Hamscope has an ability to interface with YPLOG. This feature was > not tested. > > Overall: > A VERY NICE program. If RTTY performs for you better than it did for me, > then I would say it is an EXCELLENT program. The $50.00 to register the > program (and unlock some of the PTT and Radio PTT features) may seem a > little steep to those used to the free versions of Digipan, WinPsk > WinWarbler, Zakanaka, Stream , Logger, and MMTTY. However if you want them > all in one package, the $50.00 may be worth it. Hamscope performs as well as > TrueTTY and MixW which also cost money but Hamscope certainly looks better > than those two programs. MixW 2.0 is in beta testing and it may well be > that MixW will have enough improvements to cause the ham to have much > difficulty in deciding which program to get. > > Please fee free to comment on this article. > 73 de Andy KB2EOQ > www.kb2eoq.com > obriena@&netsync.net > > Note: KB2EOQ is on the Zakanaka and MMTTY help writing teams, some > conflicts of interest are acknowledged. > _______________________________________________ > Psk31 WWW Site at http://aintel.bi.ehu.es/psk31.html > Psk31 list info at: http://aintel.bi.ehu.es/mailman/listinfo/psk31 From riese-k3djc at juno.com Mon Jan 1 16:10:56 2001 From: riese-k3djc at juno.com (robert c riese) Date: Thu Jul 3 13:43:21 2003 Subject: [Lf] probe Message-ID: <20010101.161056.-194487.1.riese-k3djc@juno.com> We will try this year Franks' newly built e-field probe that appears to exhibit a fairly remarkable (+32dBm) compression point, and may thus go a long way to avoid the Loran signal interferences we experienced last year. lets hope there field trips result in some construction projects and no frost bites. stay warm. ; } Bob K3DJC From fgentges at mindspring.com Mon Jan 1 16:26:16 2001 From: fgentges at mindspring.com (Frank Gentges =?iso-8859-1?Q?K=D8BRA?=) Date: Thu Jul 3 13:43:21 2003 Subject: [Lf] probe In-Reply-To: <20010101.161056.-194487.1.riese-k3djc@juno.com> Message-ID: <4.3.2.7.0.20010101161946.00aff170@pop.mindspring.com> AMRADers, Indeed I am working on a construction project. I hope to have a PC board available and a set of instructions in our AMRAD newsletter soon. Nags Head will be the final acid test. An earlier breadboard did pretty well down there. Hopefully the transition to the PC board will not degrade it. The PC board version tests pretty well in the lab so I am hopeful. The 3rd IP is a around +47 dBm. I want to put it in the teeth of the Carolina Beach Loran C transmitter. I have several kerosene heaters to keep warm. We would like to see you come down and participate Bob. We have room in the cottage there. It is a chance to have some radio fun. Frank At 04:10 PM 1/1/01 -0500, robert c riese wrote: >We will try this year Franks' newly built e-field probe that >appears to exhibit a fairly remarkable (+32dBm) compression >point, and may thus go a long way to avoid the Loran signal >interferences we experienced last year. > >lets hope there field trips result in some construction projects >and no frost bites. stay warm. > >; } > >Bob K3DJC > >_______________________________________________ >lf mailing list >lf@amrad.org >http://www.amrad.org/mailman/listinfo/lf From fgentges at mindspring.com Mon Jan 1 18:08:32 2001 From: fgentges at mindspring.com (Frank Gentges =?iso-8859-1?Q?K=D8BRA?=) Date: Thu Jul 3 13:43:21 2003 Subject: [Lf] probe In-Reply-To: <02e701c07445$9463ae60$53cd3ccc@mshome.net> References: <4.3.2.7.0.20010101161946.00aff170@pop.mindspring.com> Message-ID: <4.3.2.7.0.20010101174734.00af6d20@pop.mindspring.com> Paul, At 05:52 PM 1/1/01 -0500, you wrote: >Hello Frank, > >I am very interested in the E-field probe you are working on. >I wonder what the input device is that you are using in this design? A Crystalonics CP666 JFET >Is it still a very high input impedance, in the meg-ohm range? > The 3rd IP of +47 seems almost unattainable. We are running the CP666 at 24 v and 65 ma. It could qualify as a small transmitter. >Even some of the best MMIC's are only in the low 30's They don't have the heat sinking to allow the bias point to be cranked up. If the LF radio amateurs new to LF are to work against Loran C and AM broadcast stations, we needed to work hard to find a way to get it up there. I had some help on key aspects from Dallas Lankford and he deserves a tip of the AMRAD hat for his contributions. >Is there a diagram posted somewhere. It will be in the AMRAD Newsletter article. I have concentrated on using parts, skills and tools available to anyone. In addition, I am working with FAR Circuits on making the PC boards available. I include a power supply with low capacitance to the AC line and the receivers. A 2 channel output is provided so you can run 2 receivers at a time. Oh, by the way, it goes to 30 MHz so it is a decent SWL antenna. I hope to develop a calibration factor for it to allow the ham to use a surplus selective voltmeter with the antenna to measure field strength in volts/meter but that is downstream. >Thanks for your time Frank > >Paulc >W1VLF > >Cloudbounce Webpage http://www.qsl.net/w1vlf/ >Rescue Electronic Surplus http://www.rescueelectronics.com > >1982 Vanagon Diesel Turbo Diesel 1.9 >GE Electrak E20 and E15 electric tractors >First place in local tractor pulls at 1750 LBS >With Stock E-20 Electric tractor > >----- Original Message ----- >From: "Frank Gentges K?BRA" >To: "robert c riese" ; >Sent: Monday, January 01, 2001 16:26 PM >Subject: Re: [Lf] probe > > > > > > > > AMRADers, > > > > Indeed I am working on a construction project. I hope to have a PC board > > available and a set of instructions in our AMRAD newsletter soon. Nags > > Head will be the final acid test. An earlier breadboard did pretty well > > down there. Hopefully the transition to the PC board will not degrade > > it. The PC board version tests pretty well in the lab so I am > > hopeful. The 3rd IP is a around +47 dBm. I want to put it in the teeth >of > > the Carolina Beach Loran C transmitter. > > > > I have several kerosene heaters to keep warm. We would like to see you > > come down and participate Bob. We have room in the cottage there. It is >a > > chance to have some radio fun. > > > > Frank > > > > At 04:10 PM 1/1/01 -0500, robert c riese wrote: > > > > > > > > >We will try this year Franks' newly built e-field probe that > > >appears to exhibit a fairly remarkable (+32dBm) compression > > >point, and may thus go a long way to avoid the Loran signal > > >interferences we experienced last year. > > > > > >lets hope there field trips result in some construction projects > > >and no frost bites. stay warm. > > > > > >; } > > > > > >Bob K3DJC > > > > > >_______________________________________________ > > >lf mailing list > > >lf@amrad.org > > >http://www.amrad.org/mailman/listinfo/lf > > > > > > _______________________________________________ > > lf mailing list > > lf@amrad.org > > http://www.amrad.org/mailman/listinfo/lf > > Frank K0BRA From akestelo at bellatlantic.net Tue Jan 2 14:53:08 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:22 2003 Subject: [Lf] 13-14 January/EU->NA ? Message-ID: <3A5231A4.23EE2C00@bellatlantic.net> Hello Friends, The week-end of 13-15 January 2001 is a holiday week-end in the USA and, once again this year, adventurous members of the AMRAD LF fraternity will proceed to Nags Head (North Carolina) to set up various receiving gear and listen for: * European Amateur LF transmissions, (135-137) * Canadian Amateur LF Transmissions, (135-137) * LowFer US transmissions, (160-190) * European LF Broadcasters, (150-240 kHz) and * Aero navigation beacons Equipment, to include professional/ex-military communications receivers, laptops loaded with Spectran, large loops and e-field probes, will be set up both at Frank Gentges K0BRA's beach cottage and, weather permitting, on the beach proper (which last year yielded a slightly better noise level, and also peaked the interest of the local Constabulary). We will try this year Franks' newly built e-field probe that appears to exhibit a fairly remarkable (+32dBm) compression point, and may thus go a long way to avoid the Loran signal interferences we experienced last year. We have established in the past that 1800h-2400h local time (2300-0500 Zulu) is about the best time period for us to receive European Long-wave broadcast (such as France-Inter). Hence we will be listening Saturday 13 January at 2300Z until Sunday 14 at 0500Z and again from Sunday 14 at 2300Z until Monday 15 January 0500Z. Please let us know who will be transmitting what (QRSS ?) and on what frequencies. Last year, the British amateurs who agreed to transmit that week end managed to coordinate their transmitting frequencies so that these would all be clustered and may be observed on only _one_ Spectran screen. Spacing of 10Hz between stations is fine. Also silent periods of 30 seconds between ID transmissions will allow us to better identify for sure whether we are seeing a real weak amateur signal, or simply hallucinating because we have been staring at those screens for too long :-) We will have Internet access at Nags Head, and like last year, will be able to call you over the telephone if successful. 73 Andre' N4ICK From riese-k3djc at juno.com Mon Jan 1 20:18:13 2001 From: riese-k3djc at juno.com (robert c riese) Date: Thu Jul 3 13:43:22 2003 Subject: Fw: Re: [Lf] probe Message-ID: <20010101.205731.-173629.0.riese-k3djc@juno.com> and may the propagation gods be with you ,one and all Bob , Indeed I am working on a construction project. I hope to have a PC board available and a set of instructions in our AMRAD newsletter soon. Nags Head will be the final acid test. An earlier breadboard did pretty well down there. Hopefully the transition to the PC board will not degrade it. The PC board version tests pretty well in the lab so I am hopeful. The 3rd IP is a around +47 dBm. I want to put it in the teeth of the Carolina Beach Loran C transmitter. From akestelo at bellatlantic.net Wed Jan 3 08:50:02 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:22 2003 Subject: [Lf] Decca for the MLK week end Message-ID: <3A532E0A.A02832E4@bellatlantic.net> G0MRF@aol.com wrote: > In a message dated 1/2/01 9:58:57 AM GMT Standard Time, G0MRF writes: > > << > Dear Laurie. > I am trying to organise access to the West London tower block for the > transatlantic tests on the night of Saturday 13th. > > For the past couple of weeks I've planned to use the site with about > 400Watts from a standby TX thereby leaving the Decca with you. > > However, with Andre's announcement of the AMRAD LF groups weekend 'on the > beach' I feel there is a remote chance of getting a signal down into North > America and I really need to run a little more ERP. > > I need to confirm the availability of the site first, but if I get the > necessary permission, then my next trip to the South Coast is scheduled for > 10th January. > > Hope this is OK > > Vy 73 > > > David > >> > > Well done Andre'. > That weekend is going to be busy. - More details later. > > Good luck > > David 'MRF > > ------------------------------------------------------------ > > Subject: Re: Decca. > Date: Tue, 2 Jan 2001 04:58:57 EST > From: G0MRF@aol.com > To: LAURIE@g3aqc.freeserve.co.uk, G0MRF@aol.com > > Hello Laurie. > > I trust you had a good Christmas and new year. > > I am trying to organise access to the West London tower block for the > transatlantic tests on the night of Saturday 13th. > > For the past couple of weeks I've planned to use the site with about 400Watts > from a standby TX thereby leaving the Decca with you. > > However, with Andre's announcement of the AMRAD LF groups weekend 'on the > beach' I feel there is a remote chance of getting a signal down into North > America and I really need to run a little more ERP. > > I need to confirm the availability of the site first, but if I get the > necessary permission, then my next trip to the South Coast is scheduled for > 10th January. > > Hope this is OK > > Vy 73 > > David From akestelo at bellatlantic.net Thu Jan 4 08:52:22 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:22 2003 Subject: [Lf] Freq stability Message-ID: <3A548016.2FE98A8F@bellatlantic.net> Talbot Andrew wrote: > -----Hi. I am nearing the end of writing my > column in the local amateur radio journal and I > am a bit thin on > frequency stability guidelines for working QRSS > and BPSK on LF. Nobody in ZL has yet got going > on these modes but I want to publish info that > does not give any locals a bum steer as to what > to do to get into digital modes on LF. > Could you fire me some summary comments on what > frequency stability should be achieved by > transmitters and receivers to join the game, for > respective modes?Cheers,Bob ZL2CA > > Hi Bob - I've copied this reply to the LF Group as well > for general information...........QRSS ( 'SLOWCW', why > invent meaningless Q codes for the sake of it) as usually > practiced now, calls for a resolution bandwidth of 0.3Hz > or wider in order to see the 3s dot period. But as this > mode is always viewed on a spectrogram display generated > from an FFT, we are actually seeing a large chunk of > spectrum, typically many 10s to 100Hz simultaneously and a > drift of a 1Hz or so probably won't be noticed. Thus the > frequency stability needed for this mode can be a very > poor 10 parts per million - which even the cheapest and > nastiest crystal can manage - hence one of the > popularities of the mode. A 10s dot peroiod is > occasionally used calling for a 0.1Hz bin size or less but > still a few ppm accuracy will suffice.For BPSK, a > frequency stability of the order of a tenth the bit rate > is needed,a lthough a figure of better than this speeds > initial lock up. Once locked, the frequency can drift > outside this range, and manual assistance ina chieving > initial lock by 'nudging' the tuning process can allow > worse initial frequency setting accuracy. So for the > 100ms (10B/s) rate we normally use, 1Hz stability is > ideally needed, better to aim for 0.2Hz and not have to > play around with initial acquisition - still well within > the capabilities of any crystal oscillator.So to > summarise, by recommending crystal oscillator stabilities > you won't be giving any wrong steers - 1 part per million > should be the stability people should really aim for, but > a factor or so worse than this can still be useable with > Spectrogram type modes.I myself use a Direct Digital > Synthesizer source driven routinely by a TCXOo scillator > adjusted up for a repeatable 0.1ppm. The DDS tunes in > 0.001 Hz steps and without accurate calibration achieves > 0.03Hz accuracy, with calibration against off air signals > (eg MSF in the UK) 0 .001Hz is possible. For times when > some distant stations actually get set up for some serious > experimentation with very narrow band modes, I have > Droitwich and TV sync locked frequency sources - both > hangovers from microwave operating, (all home station > operators and several /P have constructed one or the other > of these). All these give a frequency setting accuracy of > a few parts in 10^-9 - about 1mHz at 137k.For calibration > purposes, a GPS receiver giving 1s pulses drives the > external clock of a frequency counter allowing 1000s / > 10ks (2.78 hour) or 100ks (just over 1 day) gating > periods. Also have a Caesium standard but prefer to > only turn it on once in a while when needed as the tube is > nearing the end of its life and its usefulness for LF is > debateable. For calibration the GPS pulses are traceable > to international standards and can be used immediately, > whereas the Cs standard would need to be set up each time > and run for several days to guarantee its few parts in > 10^-11 accuracy.Sorry to sound a bit cynical about LF > frequency accuracies and stabilities, but having spent > over 10 years with narrowband operation on the microwaves > bands,o ften from exposed portable locations, where the > 1ppm accuracy that very few LF operators bother to aim for > is several SSB bandwidths, I am rather surprised at the > difficulties many seem to have and the poor stabilities > still being seen on LF now. At least the disgusting LC > oscillator has faded out, but the norm now seems to be two > VCXOs mixed, which I suppose is comparable to an LC VFO on > the HF bands, not something seen too often now, > fortunately. Up on 10GHz a low cost crystal heater is > the minimum anyone ever uses and 1ppm is usually the > result. Operators routinely calibrate with beacons and > other stations throughout an operating period and everyone > knows at least when they are within a 3kHz SSB bandwidth > tuning range.Ironically, HF has the lowest requirement for > frequency stability. With ionosphericp ropagation causing > several Hz shifts over minutes, as well as multipath with > several millisecond delays, who needs better than 0.2 ppm > frequency accuracy?Andy G4JNT > > -- > The Information contained in this E-Mail and any > subsequent correspondence > is private and is intended solely for the intended > recipient(s). > For those other than the recipient any disclosure, > copying, distribution, > or any action taken or omitted to be taken in reliance on > such information is > prohibited and may be unlawful. From akestelo at bellatlantic.net Thu Jan 4 17:35:38 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:22 2003 Subject: [Lf] [Fwd: LF: FW: 13-14 January/EU->NA ?] Message-ID: <3A54FABA.79C9D829@bellatlantic.net> Gang, Will anyone going to Nags Head be equipped with BPSK reception capabilities ? Andre' N4ICK ***************************** Talbot Andrew wrote: > If you can manage it, how about BPSK reception on 1000MS (1 bit / > second) with suitable frequency stability. I reckon this, possibly with > Grab enabled as well, may allow reception of those with less than 1W ERP > - vested interest here :-) > > Andy G4JNT > > > >Equipment, to include professional/ex-military > >communications receivers, laptops loaded with Spectran, > >large loops and e-field probes, will be set up both at Frank > >Gentges K0BRA's beach cottage and, weather permitting, > >on the beach proper (which last year yielded a slightly > >better noise level, and also peaked the interest of the > >local > >Constabulary). > > >Please let us know who will be transmitting what (QRSS ?) > >and on what frequencies. > > -- > The Information contained in this E-Mail and any subsequent correspondence > is private and is intended solely for the intended recipient(s). > For those other than the recipient any disclosure, copying, distribution, > or any action taken or omitted to be taken in reliance on such information is > prohibited and may be unlawful. From akestelo at bellatlantic.net Thu Jan 4 20:51:38 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:23 2003 Subject: [Lf] AGC look-up tables and error control loops] Message-ID: <3A5528AA.735AC164@bellatlantic.net> ROBERT EVANS wrote: > There have been receiver designs where the AGC voltage drives an A/D and > > the D is the address to a look-up table ROM. The contents of the memory > > is fed to a D/A to drive the front panel meter. The ROM is burnt with > the > table to calibrate the meter to the correct S meter reading. This was a > > discreet circuit built into the receiver back when receivers didn't even > have > microprocessors to meet military/commercial/industrial demands for > accurate meter reading specifications. I wonder how often this is > correctly > done in present day receivers were it would be an integral part of the > display control microprocessor. > > But, on the subject of AGC... > > Many digital modems offer an output signal to control the gain ahead of > the A/D. Some technique is used to determine if the A/D is being fully > filled without unacceptable compression thus offering the maximum > dynamic range. If not, a control signal increases or decreases the > gain > of the analogue stages ahead of the A/D. > > There are many ways of implementing this from simply processing the > most significant bit to have a specified duty cycle to involved > algorithms > that take into account the degree of the distortion that the modulation > and encoding scheme can handle. > > It would be useful, for instance, if the software controlled a pin (or > pins) > on the com port to describe how to adjust the audio level. This > would offer a much more appropriate method of implementing an AGC > loop. > > For example, a PWM signal on a single pin could be integrated to produce > > a control voltage. Two pins could offer a more straight foward error > signal pair of too high / too low. A receiver could make use of this > signal to control its gain stages instead of a separate analog detector > based AGC system. > > BCNU DE N2LO~> > _______________________________________________ > Psk31 WWW Site at http://aintel.bi.ehu.es/psk31.html > Psk31 list info at: http://aintel.bi.ehu.es/mailman/listinfo/psk31 From akestelo at bellatlantic.net Fri Jan 5 09:40:23 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:23 2003 Subject: [Lf] [Fwd: LF: Frequency stability] Message-ID: <3A55DCD7.7A19B012@bellatlantic.net> Dick Rollema wrote: > To All from PA0SE A simple system combining the > flexibility of a VFO with the stability of a quartz > crystal is a V FO + "Huff and Puff" frequency stabiliser. > This device frequency-locks the VFO to the nearest one of > a series of frequencies that increase in steps of for > instance 32Hz and are derived from a crystal. Take for > instance a VFO in the 8MHz range and a stabiliser with > 32Hz raster. When divided by 64 down to 136kHz the > frequency steps become 0.5Hz. After manually tuning the > VFO the frequency creeps towards the nearest raster point > which is never more than 0.25Hz away and it stays > there. When a crystal at room temperature is not good > enough a TCXO could be used. The "Huff and Puff" system > was designed by the late Klaas Spaargaren, PA0KSB and > described in many articles in among others RadCom and Ham > Radio. Also in my copy of the fifth edition of Pat Hawkers > Amateur Radio Techniques and possibly in later editions as > well.Mike, G3XDV, publications manager of RSGB, can no > doubt tell you more about this. I use a "Huff and Puff" > stabiliser on the VFO of my valved HF-band transmitter and > it functions exactly as expected. I would certainly add > one to the 8MHz VFO of my LF-band transmitter if I were to > use QRSS. For normal CW the VFO in itself is stable > enough. 73, Dick, PAoSE From akestelo at bellatlantic.net Fri Jan 5 09:40:23 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:23 2003 Subject: [Lf] [Fwd: LF: Frequency stability] Message-ID: <3A55DCD7.7A19B012@bellatlantic.net> Dick Rollema wrote: > To All from PA0SE A simple system combining the > flexibility of a VFO with the stability of a quartz > crystal is a V FO + "Huff and Puff" frequency stabiliser. > This device frequency-locks the VFO to the nearest one of > a series of frequencies that increase in steps of for > instance 32Hz and are derived from a crystal. Take for > instance a VFO in the 8MHz range and a stabiliser with > 32Hz raster. When divided by 64 down to 136kHz the > frequency steps become 0.5Hz. After manually tuning the > VFO the frequency creeps towards the nearest raster point > which is never more than 0.25Hz away and it stays > there. When a crystal at room temperature is not good > enough a TCXO could be used. The "Huff and Puff" system > was designed by the late Klaas Spaargaren, PA0KSB and > described in many articles in among others RadCom and Ham > Radio. Also in my copy of X-Mozilla-Status: 0009at Hawkers > Amateur Radio Techniques and possibly in later editions as > well.Mike, G3XDV, publications manager of RSGB, can no > doubt tell you more about this. I use a "Huff and Puff" > stabiliser on the VFO of my valved HF-band transmitter and > it functions exactly as expected. I would certainly add > one to the 8MHz VFO of my LF-band transmitter if I were to > use QRSS. For normal CW the VFO in itself is stable > enough. 73, Dick, PAoSE From akestelo at bellatlantic.net Fri Jan 5 11:20:08 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:23 2003 Subject: [Lf] Freq stability, cheap source of] Message-ID: <3A55F437.13BE965F@bellatlantic.net> Larry Kayser wrote: > Greetings All: > > There is a very cheap source of very high stability reference available to > everyone. It is the 1 PPS from almost any second hand OEM level GPS > receiver. I have one here that cost $20 US$, about the size of what we once > called a penny folder of paper matches. I did a little poking around on the > Internet over a year ago and found a chap selling Garmin GPS OEM Model 20 > and 25 units complete with the external connector. The unit I have here > runs happily on 5V. The removal of selective availability (SA) last year > means only the 5% of the time basic jitter is left, references are possible > to stabilities in a few parts in 10 - 11th. > > Brooks Shera published an excellent article in QST on "disciplining" a > frequency standard to the GPS 1 PPS signal. > > see http://www.rt66.com/~shera/index_fs.htm > > Hope this might help some find a way to improve stability on LF > > Larry > VA3LK From akestelo at bellatlantic.net Fri Jan 5 09:09:39 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:23 2003 Subject: [Lf] ARGO Message-ID: <3A55D5A2.DDD71720@bellatlantic.net> Alberto di Bene wrote: > Peter Dodd wrote: > > > [snip] > > I set the receiver to 136kHz SSB USB. Argo, on 'Full Band View'. The > > band from 136.0 to 137.5kHz can be seen and any signal can be > > selected and zoomed, a wonderful tool for monitoring. > > [snip] > > As a matter of fact, build 113 has a full band view span from 0 to 2756 HZ, > thus covering all of the 136 kHz band. Just click the left mouse button when > on the upper frequency scale and, keeping the mouse button down, drag left > or right the scale to see the desired portion. > I will upload build 113 this evening or tomorrow, after some final touches. > Peter and Mike had a preversion in advance, to see if it solved their screen > size problems (it did). > > 73 Alberto I2PHD From akestelo at bellatlantic.net Thu Jan 4 22:15:11 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:24 2003 Subject: [Lf] [Fwd: LF: 12 /13th Jan.] Message-ID: <3A553C3F.A711F390@bellatlantic.net> G0MRF@aol.com wrote: > Hello All. > > Just to confirm that I have arranged access to my /P site at the West London > tower block and should be participating in the tests. Unfortunately, this > will only be on the Saturday night / Sunday morning. > > Can anyone confirm my rough measurement of SVX as apx. 135.671 to 135.776 > The upper and lower edges of the data seem to contain more energy and I > suppose should be avoided. > > 73 > > David G0MRF From akestelo at bellatlantic.net Fri Jan 5 18:13:05 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:24 2003 Subject: [Lf] Geek gadgets Message-ID: <3A565500.3FD53449@bellatlantic.net> GEEK GADGETS by Dave Murphy, member@itrain.org This article isn't news by any means. It's a reprint of an article I wrote yesterday for a column I keep in a business newspaper. I don't make this list to advertise the products, just to be specific in noting these specific items are my recommendations. Everybody wants technology toys (at least all the men in the audience do!). This year will be a bonanza for high-tech gizmos that will make your head spin. Here?s my list of favorite items, none of which will break your bankroll. 1. Olympus D-490 Digital Zoom Camera With new QuickTime movie features, convenient options and zoom capabilities, the D-490 Zoom is boldly going into the photographic future. The D-490 Zoom makes the leap to a 2.11 megapixel point-and-shoot digital camera and features a high-quality 3X optical zoom lens designed for digital photography along with the ever-popular 2X digital telephoto. The combination provides you with a pocket camera having a 35mm equivalent zoom range of 35 to 105mm and 210mm digital. With the QuickTime movie mode you can now film mini motion pictures with your D-490 Zoom camera. 2. Handspring Visor Prism Handheld Computer Now you can add color to your life. The Handspring Visor Prism is first infinitely expandable full-color handheld computer. It displays over 65,000 vibrant colors so everything is crisper, brighter and easier to read. And, with the Springboard expansion slot, you can snap in a digital camera or a global positioning system and instantly view full-color pictures, maps and more. 3. Nokia 8260 Mobile Phone With the latest in style and design, the Nokia 8260 mobile phone has striking good looks and an impressive list of features. This is the mobile phone to supercharge your mobile lifestyle. It?s small enough to fit in the palm of your hand, and the battery lasts for eight days! All told, it weighs 3.4oz. which is light enough to carry around a shirt pocket. 4. Yamaha CRW2100EZ CD-RW Burner This 16x speed CD burner will make short work of your computer data backups or music files. With an 8MB data buffer, this is currently the fastest stock burner on the market--this baby is the one to have! It requires a standard E-IDE connection, and will work on any standard PC. (There?s also a SCSI version if you?re a Mac aficionado.) 5. Epson Stylus Color Printer You need any one of the Epson Stylus color printers. They?re all great. Beware though, the ink cost per page runs about $0.02 to $0.12. So, a pile of high-res photos or brochures will run through some ink. There?s a brisk after-market distribution of ink cartridges for the 1440dpi printers that will cut up to 70% off your ink cost. The 2880dpi model printers only accept full-price Epson-brand ink. Color printers and the ink they consume are kind of like hamsters and their accessories. The printers are cheap because the manufacturer plans to make money on all the ink you?re sure to use. Look for printers that use less-expensive ink! 6. Targus Stowaway Portable Keyboard Don?t get a Handspring Visor or any PalmOS handheld computer without also picking up the Stowaway folding keyboard to go with it. With a 4-fold mechanism, this baby ties up smaller than the handheld computer! Full-size keys let even calloused paws of the toughest construction worker get in there track expenses and keep the appointment calendar filled. 7. Audiovox FRS Walkie-Talkies Running about the same size as the Nokia 8260 digital cell phone, these Family Radio Service (FRS) handhelds fit into your shirt pocket and give unlimited free calls within about a 2-mile range. Use ?em at the store, the amusement park, anywhere you want to stay in touch. I use them around the office and take ?em home when working in the attic or out in the yard. 8. Garmin International eTrex Handheld GPS Truly a small wonder, the eTrex takes the best features of a 12-parallel channel GPS receiver and put them into a 6oz. package that?s only four inches high. The unit easily fits in the palm of your hand. Besides its small size, mariners and outdoorsmen will likely notice the sleek design of the eTrex. All buttons are located on either side of the unit, allowing for simple, one-handed operation that won't obstruct your view of the display. Thanks to its bright yellow case, the eTrex will be hard to misplace and easy to find in any boat or backpack. The eTrex is completely waterproof so it can take an accidental splash or dunk in the water and still continue to perform. The eTrex will store up to 500 user waypoints with graphic icons and boasts Garmin's exclusive TracBack feature that will reverse your track log and help you navigate your way back home. In addition, the eTrex uses animated graphics that will help you identify your marked waypoints quickly and easily. 8. Sony MZ-R90 MD Walkman Sony's stylish MZ-R90 MD Walkman Player Recorder is the world's smallest and lightest recording MD Walkman. Featuring long playback and recording times, the MZ-R90 was created for movers and shakers, like you. Now you can take your favorite tracks to the office with you. The recordable minidisks look like tiny CDs, and they hold hours of music: best of all, they?re reusable! 9. Logitech QuickCam Pro 3000 Computer Camera The newly designed camera features a high-resolution 640 x 480 (VGA) CCD sensor. Its built-in microphone allows users to make live video calls and send video email with streaming audio. Experience increased web activity performance with reduced upload times for web cams, as well as a simplified sign-up procedure for SpotLife personal video broadcasting. You?ll easily find your way among numerous activities within the application, including video email, live video web broadcasts, and video conferencing. I thought it would be tough to come up with a half dozen or so geek toys. But then I hit on the idea to just look around the office. I just reported on stuff I either already have or have put on my wish list. Call for Comments What do you think? Leave your comments on the message center: http://itrain.org/msg/ From akestelo at bellatlantic.net Sat Jan 6 08:53:57 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:24 2003 Subject: [Lf] Home Brew PSK31 Message-ID: <3A572375.4531A087@bellatlantic.net> Graeme Zimmer wrote: > Hi Folks, > > If you are interested in Home Brew PSK31 you may wish to visit my Web Page > at.. > > http://www.users.bigpond.com/gzimmer/ > > Cheers ................... Zim .................. VK3GJZ From akestelo at bellatlantic.net Sat Jan 6 11:26:08 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:24 2003 Subject: [Lf] The dangers of LF... Message-ID: <3A574720.26419A77@bellatlantic.net> Dave wrote: > Dear all. > > I've just had a bit of a disaster! > > http://www.wireless.org.uk/newspic38.htm > > 73. Dave G3YXM. From randy at pobox.com Sat Jan 6 13:32:23 2001 From: randy at pobox.com (Randy Mays) Date: Thu Jul 3 13:43:25 2003 Subject: [Lf] Re: The dangers of LF... References: <3A574720.26419A77@bellatlantic.net> Message-ID: <008301c0780f$0391c020$f16daccf@win.net> I hope this is a good lesson for everybody. Many of you laughed at me when I said I'd have no part of these evil LF experiments because there were unknown dangers. Now we'll see who gets the last laugh! Ha! Randy P.S. But I am finding this PSK stuff interesting. ----- Original Message ----- From: Andre' Kesteloot To: lf-amrad ; AMRAD Tacos Sent: Saturday, January 06, 2001 11:26 AM Subject: The dangers of LF... > > > Dave wrote: > > > Dear all. > > > > I've just had a bit of a disaster! > > > > http://www.wireless.org.uk/newspic38.htm > > > > 73. Dave G3YXM. > > > > _______________________________________________ > Tacos mailing list > Tacos@amrad.org > http://www.amrad.org/mailman/listinfo/tacos > From akestelo at bellatlantic.net Sat Jan 6 16:40:36 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:25 2003 Subject: [Lf] Re: The dangers of LF... References: <3A574720.26419A77@bellatlantic.net> <008301c0780f$0391c020$f16daccf@win.net> Message-ID: <3A5790D3.2F89A687@bellatlantic.net> Randy Mays wrote: > I hope this is a good lesson for everybody. Many of you laughed at me when > I said I'd have no part of these evil LF experiments because there were > unknown dangers. Now we'll see who gets the last laugh! Ha! Randy I absolutely agree with you: a) the UK Government should do something about it (like putting more TV cameras to check people's gardens) b) the US EPA should step in too (how about warning labels on all coils?) 73 Andre' From akestelo at bellatlantic.net Sun Jan 7 10:12:01 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:25 2003 Subject: [Lf] Tests with PSK31, PSK10 and more..] Message-ID: <3A588741.F83607F5@bellatlantic.net> DL4YHF@aol.com wrote: > Hello group, > > Just did a few tests (off-air) using a slow variant of PSK31 which could be > called PSK10, PSK05 etc. > Instead of the signaling rate of 31.25 symbols/second from G3PLX's original > PSK31, I used only 10 or 5 symbol/second. This reduces the bandwith to 1/3rd > or 1/6th of the original PSK31 signal, and thanks to the nice coding scheme > used in PSK31, the character transmission speed is still acceptable for a > 'real' QSO. > ( For those who are not familiar with PSK31: > It uses a code set called 'Varicode', > which uses fewer bits for frequent letters like 'e' > than the others, similar to the Morse code.) > > To test the effect of the reduced symbol rates, I added white noise to the > signal and compared the decoded text with the original PSK31. I decreased the > signal/noise ratio until the decoded text became undetectable. > The results were as expected: Using "PSK10" instead of "PSK31", the noise > could be increased about 3 times in amplitude for the same detection quality. > > However, if you want to test the 'slow PSK31 variants' on air. Because all > PSK31 programs I had did not support other symbol rates than 31.25sym/sec, I > modfied the PSK modulator and detector from WinPSK (by AE4JY) and stuffed > them into Spectrum Lab. > I just uploaded a new release of SpecLab (V1.63) with a built-in 'digimode > terminal'. It is available at www.qsl.net/dl4yhf/spectra1.html. Beta testers > are welcome. Bug reports please to DL4YHF@qsl.net. How about some 'QRPP' > tests, Geri ? > > ------------ snip ------------ > Drifting frequency of DF0WD's CW signal: > The problem is a result of the poor stability of the main oscillator in my > old Icom IC706. The fan blows warm air from the final amp towards the 'master > crystal'. I watched the Loran lines yesterday, and found them 'wandering' > around the sreen for about 30 seconds after one over (using only normal CW > here). > I thought about buying a 'TCXO' for the IC706, but the cost of about 120euro > for that tiny piece of PCB kept me off. Any better ideas ? > ----------- snip ----------- > > 73's Wolf (DL4YHF, qrv on LF only from DF0WD). From akestelo at bellatlantic.net Sun Jan 7 17:07:35 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:25 2003 Subject: [Lf] EU -> NA freqs Message-ID: <3A58E8A7.868AFA2C@bellatlantic.net> In a message dated 1/7/01 5:38:50 AM GMT Standard Time, akestelo@bellatlantic.net writes: << Gentlemen, the time has come for all of us to arrive at some agreement as to which frequencies you (UK Guys) propose to use during the coming week-end, so that we (US Guys from the former Colonies) may look at as small a portion of the spectrum as possible. Hello Andre. I plan to be on 135.955 from 22.00 on Saturday 13th to 05.30 Sunday 14th. To be spectrum efficient I will be sharing the frequency with Petr OK1FIG. He will be active Friday evening to Saturday Morning only. I will have to use a schedule but it needs The Canadians to decide. If this is not adopted I will suffer IMD problems in my receive pre-amp. Should you see any sign of the signal, the apartments phone number is: +44 20 8893 7976 You may stand a good chance if anyone has an EVM 56002 board capable of looking in the milliHz region. G4JNT has software. If you need a long transmission for identification, please call and I can switch to carrier only etc. Schedule via rsgb reflector. Will you have e-mail / HF / etc. 73 David G0MRF From akestelo at bellatlantic.net Tue Jan 9 09:48:17 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:25 2003 Subject: [Lf] [Fwd: LF: Weekend tests] Message-ID: <3A5B24B1.4C56E3AA@bellatlantic.net> Mike Dennison wrote: > This weekend, there is the greatest opportunity yet to make the > transatlantic two-way. > > I would like to suggest some procedures to maximise that > opportunity and minimise mutual QRM. Please feel free to point out > any flaws in my argument. > > As far as possible, continuous beaconing should be avoided, > especially if another station is operating near to you. > > Transmission slots to be 15 minutes: VE1ZZ transmits from 00 and > 30 minutes past the hour, Eu stations transmit from 15 and 45 > minutes past the hour. Send just your own callsign and wait for Jack > to identify you. If a QSO happens, all other stations to stop > transmitting. > > There is a frequency plan at http:www.lf.thersgb.net/transatlantic.htm > using the sub-band 135.9-136.0kHz. This includes the Loran > frequencies for the Canadian end. It is intended for guidance only, > but it will probably help the chances of success if we make an effort > to avoid each other. It will also help John/Jack/Larry and the > AMRAD team to know which frequency to find what station. Please > e-mail me any updates. > > If it helps, I can post telephone numbers on that web page, too (they > can be removed after the event). > > I will post a separate message reminding QRSS novices of > procedures. > > Good luck! > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From akestelo at bellatlantic.net Tue Jan 9 09:49:23 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:26 2003 Subject: [Lf] [Fwd: LF: QRSS procedure] Message-ID: <3A5B24F3.223AE5A1@bellatlantic.net> Mike Dennison wrote: > QRSS can be confusing for anyone new to it, and any errors can > be very time-consuming. I have seen people send zero instead of O, > wasting several minutes, as well as QTH, power level etc. The idea is > to be as brief as possible whilst keeping the message clear. > > Rik, ON7YD has a useful web page showing a typical QSO, and I > can recommend it to anyone new to QRSS. It is at > http://www.qsl.net/on7yd/136narro.htm > > I suggest for this weekend a slightly shorter format than shown by > Rik. A QSO could progress as follows: > > VE1ZZ: "VE1ZZ VE1ZZ VE1ZZ" etc for 15 minutes. > G3XDV: "G3XDV G3XDV G3XDV" etc for 15 minutes. > VE1ZZ: "G3XDV G3XDV M M K" > G3XDV: "ZZ R O O K" > VE1ZZ (not copying): "? ? K" > G3XDV: "ZZ R O O K" > VE1ZZ: "XDV R R SK" > > There is no need to send '73' or 'TU', just 'SK'. > Don't use 'QRZ' or 'AGN', and certainly not 'PSE RPT' - just '?' will do. > Don't use full callsigns once the QSO has started, the suffix is > enough. > Only use the other station's callsign during the QSO. If you are > unsure that the DX replied to you, it is permissible to use your own > suffix as well but without the 'DE' (G3XDV: ZZ XDV O O K). > Never use RST - the reporting system is: > 'T' = Seen but not readable. > 'M' = Readable but not 100%. > 'O' = 100% of every character seen clearly. > > The golden rule is not to send anything that is not needed. A QRSS > QSO can take 45 minutes. Using this procedure it will reduce to less > than 30. > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From akestelo at bellatlantic.net Tue Jan 9 09:49:23 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:26 2003 Subject: [Lf] [Fwd: LF: QRSS procedure] Message-ID: <3A5B24F3.223AE5A1@bellatlantic.net> Mike Dennison wrote: > QRSS can be confusing for anyone new to it, and any errors can > be very time-consuming. I have seen people send zero instead of O, > wasting several minutes, as well as QTH, power level etc. The idea is > to be as brief as possible whilst keeping the message clear. > > Rik, ON7YD has a useful web page showing a typical QSO, and I > can recommend it to anyone new to QRSS. It is at > http://www.qsl.net/on7yd/136narro.htm > > I suggest for this weekend a slightly shorter format than shown by > Rik. A QSO could progress as follows: > > VE1ZZ: "VE1ZZ VE1ZZ VE1ZZ" etc for 15 minutes. > G3XDV: "G3XDV G3XDV G3XDV" etc for 15 minutes. > VE1ZZ: "G3XDV G3XDV M M K" > G3XDV: "ZZ R O O K" > VE1ZZ (not copying): "? ? K" > G3XDV: "ZZ R O O K" > VE1ZZ: "XDV R R SK" > > There is no need to send '73' or 'TU', just 'SK'. > Don't use 'QRZ' or 'AGN', and certainly not 'PSE RPT' - just '?' will do. > Don't use full callsigns once the QSO has started, the suffix is > enough. > Only use the other station's callsign during the QSO. If you are > unsure that the DX replied to you, it is permissible to use your own > suffix as well but without the 'DE' (G3XDV: ZZ XDV O O K). > Never use RST - the reporting system is: > 'T' = Seen but not readable. > 'M' = Readable but not 100%. > 'O' = 100% of every character seen clearly. > > The golden rule is not to send anything that is not needed. A QRSS > QSO can take 45 minutes. Using this procedure it will reduce to less > than 30. > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From akestelo at bellatlantic.net Tue Jan 9 09:49:52 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:26 2003 Subject: [Lf] [Fwd: LF: Re: Weekend tests] Message-ID: <3A5B2510.EDFCD7E9@bellatlantic.net> Petr Maly wrote: > Generally I agree with this plan. Only some points to be sure: > > 1. John will use his call sign VE1ZJ and will tranmit on 136.500. > 2. Test begins at about 2000 utc on Friday > 3. Used dot length will be around 3500 mS > 4. My freq is 135.955 (according to Mike's WEB) > 5. Standard T-M-O reporting system will be used > > 73 Petr OK1FIG > > ----- Original Message ----- > From: Mike Dennison > To: > Sent: Tuesday, January 09, 2001 10:45 AM > Subject: LF: Weekend tests > > > This weekend, there is the greatest opportunity yet to make the > > transatlantic two-way. > > > > I would like to suggest some procedures to maximise that > > opportunity and minimise mutual QRM. Please feel free to point out > > any flaws in my argument. > > > > As far as possible, continuous beaconing should be avoided, > > especially if another station is operating near to you. > > > > Transmission slots to be 15 minutes: VE1ZZ transmits from 00 and > > 30 minutes past the hour, Eu stations transmit from 15 and 45 > > minutes past the hour. Send just your own callsign and wait for Jack > > to identify you. If a QSO happens, all other stations to stop > > transmitting. > > > > There is a frequency plan at http:www.lf.thersgb.net/transatlantic.htm > > using the sub-band 135.9-136.0kHz. This includes the Loran > > frequencies for the Canadian end. It is intended for guidance only, > > but it will probably help the chances of success if we make an effort > > to avoid each other. It will also help John/Jack/Larry and the > > AMRAD team to know which frequency to find what station. Please > > e-mail me any updates. > > > > If it helps, I can post telephone numbers on that web page, too (they > > can be removed after the event). > > > > I will post a separate message reminding QRSS novices of > > procedures. > > > > Good luck! > > > > > > > > Mike, G3XDV (IO91VT) > > http://www.lf.thersgb.net > > > > > > From akestelo at bellatlantic.net Wed Jan 10 18:57:13 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:26 2003 Subject: [Lf] Weekend tests, the final version... Message-ID: <3A5CF6D9.C57F9A01@bellatlantic.net> "mike.dennison" wrote: > I have posted at http://www.lf.thersgb.net/transatlantic.htm a summary of > what appears to have been agreed. This includes timing, procedures and > frequencies. > > Please let me know if I have anything wrong. I hope it will help to have > everything on the one page. > > Mike, G3XDV From akestelo at bellatlantic.net Tue Jan 9 09:49:52 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:26 2003 Subject: [Lf] [Fwd: LF: Re: Weekend tests] Message-ID: <3A5B2510.EDFCD7E9@bellatlantic.net> Petr Maly wrote: > Generally I agree with this plan. Only some points to be sure: > > 1. John will use his call sign VE1ZJ and will tranmit on 136.500. > 2. Test begins at about 2000 utc on Friday > 3. Used dot length will be around 3500 mS > 4. My freq is 135.955 (according to Mike's WEB) > 5. Standard T-M-O reporting system will be used > > 73 Petr OK1FIG > > ----- Original Message ----- > From: Mike Dennison > To: > Sent: Tuesday, January 09, 2001 10:45 AM > Subject: LF: Weekend tests > > > This weekend, there is the greatest opportunity yet to make the > > transatlantic two-way. > > > > I would like to suggest some procedures to maximise that > > opportunity and minimise mutual QRM. Please feel free to point out > > any flaws in my argument. > > > > As far as possible, continuous beaconing should be avoided, > > especially if another station is operating near to you. > > > > Transmission slots to be 15 minutes: VE1ZZ transmits from 00 and > > 30 minutes past the hour, Eu stations transmit from 15 and 45 > > minutes past the hour. Send just your own callsign and wait for Jack > > to identify you. If a QSO happens, all other stations to stop > > transmitting. > > > > There is a frequency plan at http:www.lf.thersgb.net/transatlantic.htm > > using the sub-band 135.9-136.0kHz. This includes the Loran > > frequencies for the Canadian end. It is intended for guidance only, > > but it will probably help the chances of success if we make an effort > > to avoid each other. It will also help John/Jack/Larry and the > > AMRAD team to know which frequency to find what station. Please > > e-mail me any updates. > > > > If it helps, I can post telephone numbers on that web page, too (they > > can be removed after the event). > > > > I will post a separate message reminding QRSS novices of > > procedures. > > > > Good luck! > > > > > > > > Mike, G3XDV (IO91VT) > > http://www.lf.thersgb.net > > > > > > From akestelo at bellatlantic.net Tue Jan 9 09:48:17 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:27 2003 Subject: [Lf] [Fwd: LF: Weekend tests] Message-ID: <3A5B24B1.4C56E3AA@bellatlantic.net> Mike Dennison wrote: > This weekend, there is the greatest opportunity yet to make the > transatlantic two-way. > > I would like to suggest some procedures to maximise that > opportunity and minimise mutual QRM. Please feel free to point out > any flaws in my argument. > > As far as possible, continuous beaconing should be avoided, > especially if another station is operating near to you. > > Transmission slots to be 15 minutes: VE1ZZ transmits from 00 and > 30 minutes past the hour, Eu stations transmit from 15 and 45 > minutes past the hour. Send just your own callsign and wait for Jack > to identify you. If a QSO happens, all other stations to stop > transmitting. > > There is a frequency plan at http:www.lf.thersgb.net/transatlantic.htm > using the sub-band 135.9-136.0kHz. This includes the Loran > frequencies for the Canadian end. It is intended for guidance only, > but it will probably help the chances of success if we make an effort > to avoid each other. It will also help John/Jack/Larry and the > AMRAD team to know which frequency to find what station. Please > e-mail me any updates. > > If it helps, I can post telephone numbers on that web page, too (they > can be removed after the event). > > I will post a separate message reminding QRSS novices of > procedures. > > Good luck! > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net X-Mozilla-Status: 00099:49:24 2001 X-Mozilla-Status: 0801 X-Mozilla-Status2: 00000000 FCC: /C|/Program Files/Netscape/Users/akestelo/mail/Sent BCC: akestelo@bellatlantic.net Message-ID: <3A5B24F3.223AE5A1@bellatlantic.net> Date: Tue, 09 Jan 2001 09:49:23 -0500 From: Andre' Kesteloot Reply-To: andre.kesteloot@ieee.org X-Mozilla-Draft-Info: internal/draft; vcard=0; receipt=0; uuencode=0; html=0; linewidth=77 X-Mailer: Mozilla 4.7 [en]C-CCK-MCD NSCPCD47 (WinNT; I) X-Accept-Language: en MIME-Version: 1.0 To: lf-amrad , AMRAD Tacos Subject: [Fwd: LF: QRSS procedure] Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Mike Dennison wrote: > QRSS can be confusing for anyone new to it, and any errors can > be very time-consuming. I have seen people send zero instead of O, > wasting several minutes, as well as QTH, power level etc. The idea is > to be as brief as possible whilst keeping the message clear. > > Rik, ON7YD has a useful web page showing a typical QSO, and I > can recommend it to anyone new to QRSS. It is at > http://www.qsl.net/on7yd/136narro.htm > > I suggest for this weekend a slightly shorter format than shown by > Rik. A QSO could progress as follows: > > VE1ZZ: "VE1ZZ VE1ZZ VE1ZZ" etc for 15 minutes. > G3XDV: "G3XDV G3XDV G3XDV" etc for 15 minutes. > VE1ZZ: "G3XDV G3XDV M M K" > G3XDV: "ZZ R O O K" > VE1ZZ (not copying): "? ? K" > G3XDV: "ZZ R O O K" > VE1ZZ: "XDV R R SK" > > There is no need to send '73' or 'TU', just 'SK'. > Don't use 'QRZ' or 'AGN', and certainly not 'PSE RPT' - just '?' will do. > Don't use full callsigns once the QSO has started, the suffix is > enough. > Only use the other station's callsign during the QSO. If you are > unsure that the DX replied to you, it is permissible to use your own > suffix as well but without the 'DE' (G3XDV: ZZ XDV O O K). > Never use RST - the reporting system is: > 'T' = Seen but not readable. > 'M' = Readable but not 100%. > 'O' = 100% of every character seen clearly. > > The golden rule is not to send anything that is not needed. A QRSS > QSO can take 45 minutes. Using this procedure it will reduce to less > than X-Mozilla-Status: 0009(IO91VT) > http://www.lf.thersgb.net From akestelo at bellatlantic.net Tue Jan 9 09:52:01 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:27 2003 Subject: [Lf] [Fwd: LF: / Measuring receivers] Message-ID: <3A5B2590.D47635D6@bellatlantic.net> Hans-Joachim Brandt wrote: > Hi all, > > concerning s-meter reading of SSB or CW the best method I have found so far is > the principle which has been used in the old Plessey SL621 integrated circuit, a > combination of two detectors with different time constants: > One very quick, even suited to let the AVC react on short qrn or noise peaks, > the second time constant longer, which can be increased to several seconds > by removing a parallel resistor from the capacitor when the wanted signal > disappears, with also a third time constant being started when the wanted signal > disappears, in order to discharge the long time constant capacitor rapidly if > the wanted signal should not return in between the time of the third time > constant, in order to put the receiver quickly back to full sensitivity when > there is no signal any more. > > I have arranged the functions of the SL 621 around a LM324, including a few > diodes; the only thing which I have made differently is to take the AVC signal > from the I.F., not the A.F. as in the application of the SL621. The s-meter > indication will remain the same, no matter whether you speak as usually or > whistle into the microphone. > > QRN will always be a problem, I think; in my circuit this should not matter as > long as the peaks of the wanted signal are higher than the qrn peaks, otherwise > the QRN peaks would take the lead, of course. > > HW? > > 73 Ha-Jo, DJ1ZB > > James Moritz schrieb: > > Dear LF group, > > > > OK on the loading coils - my current loading coil is over 500mm > > diameter, so ready-made containers to fit it are hard to come by. > > I'm suprised that people have had success with coils exposed to > > the rain, I found with mine that this drastically reduced the Q once > > water got in between the turns. The 20kV or so across the winding > > is a bit of a worry in the wet, too. Do hardware shops in Germany > > really sell litz wire, Geri? > > > > Interesting to see details of G4JNT's portable measuring receiver > > project; on and off I have been working on something similar > > myself. A significant difficulty with measuring signal levels on LF is > > how to get a sensible reading with on/off keyed signals and > > significant levels of QRN. A strong carrier or QRSS signal is easily > > measured with any old AC voltmeter on the audio or IF output - but > > it is not always possible to arrange such a signal. However, with > > manual CW (and presumably modes like BPSK), the varying signal > > level makes it difficult to get a steady reading. I have tried using a > > "quasi peak" type voltmeter (ie. a peak detector with a few ms > > attack and much slower decay, similar to many RX s-meter > > responses). This works well with CW, but any sort of meter seems > > to have problems with QRN; since the peak QRN level is often > > much higher than even quite strong signals, you get a few dB > > variation even with long meter time constants. > > > > Perhaps the most satisfactory method is to use an oscilloscope to > > display the signal, since then you can see and identify the > > modulation envelope and QRN spikes, but this is less than > > convenient for portable use! > > > > Another measurement that is important to make is the noise level, > > but this is also highly dependent on the type of meter response. > > > > Cheers, Jim Moritz > > 73 de M0BMU > > From akestelo at bellatlantic.net Tue Jan 9 13:05:40 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:27 2003 Subject: [Lf] digital-modes software site Message-ID: <3A5B52F4.8C19D67@bellatlantic.net> Gang, a great web site for digital-modes software: 73 Andre' N4ICK http://leden.tref.nl/~nl9222tv/software.htm From akestelo at bellatlantic.net Tue Jan 9 21:44:14 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:27 2003 Subject: [Lf] ThiS week end Message-ID: <3A5BCC7D.101A68F0@bellatlantic.net> Gang, I have obtained authorization from the Fairfax Park Authority for AMRAD members to deploy LF receiving equipment at Burke Lake Park (on Rt. 123, near Lorton) this Saturday 13 and Sunday 14 January, both evenings from 1800 till midnight. Are there any volunteers to accompany me either night? Let's discuss this subject on Thursday evening, at the monthly AMRAD meeting. hanks in advance. Andre' N4ICK From akestelo at bellatlantic.net Tue Jan 9 21:51:59 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:27 2003 Subject: [Lf] LF this Weekend. Message-ID: <3A5BCE4F.CC3D7BC4@bellatlantic.net> G0MRF@aol.com wrote: > To be 'spectrum efficient' I've arranged to share the 135.955 frequency with > Petr. > OK1FIG will be QRV Friday/Sat. G0MRF/P will be active on QRSS from 22.00 > on the 13th to 05.30 Sunday morning. > > OK on the +15min and +45min TX periods Mike. That will give my pre-amp a > chance of working without IMD. > > Good luck to all. > > David G0MRF > > 0956 502540 From akestelo at bellatlantic.net Wed Jan 10 18:47:16 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:28 2003 Subject: [Lf] [Fwd: LF: Weekend tests] Message-ID: <3A5CF484.146F3C40@bellatlantic.net> James Moritz wrote: > Dear John, Jack, LF Group, > > OK, so I will send my callsign using 3s dots, starting at 15 and 45 > minutes past the hour, for about 15 mins. Assuming I can see your > signal, I will wait for you to call me before trying to send signal > reports, etc., and will wait until the beginning of the next 15 or 45 > minute period to start transmitting. This should minimise problems > with transmissions from different stations overlapping. I will stick to > the frequency plan on G3XDV's web pages, ie. 135.916kHz for me > > Please note - I don't have any E-mail facilities at home, so will not > see any e-mails until at least the day after they are sent, during the > weekend. Alternatively, I can be reached on 01707 643461. > > Best of luck to all those involved, and hope the weather is not to > wild in UK or Nova Scotia this weekend. > > Cheers, Jim Moritz > 73 de M0BMU > > From akestelo at bellatlantic.net Wed Jan 10 18:47:47 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:28 2003 Subject: [Lf] LF: canadian Weekend tests] Message-ID: <3A5CF4A3.C9ADD8E2@bellatlantic.net> John Currie wrote: > Hi Mike Sorry about not answering you. I was coordinating with Jack > Our proposal follows. > 1 Jack will tx on 136.500 . Up could have trouble with CFH down could > have trouble with SXV. please keep the freq clear. > 2Jack will tx 10 minutes at top ann bottom of each hour 3sec dots. > 3 Then Jack will tx straight cw for two minutes. > 4 we will listen 135.9to 136.05 for cw answers for 18 minutes > 5 At the same time we will look for 3sec dot qrss from 135.9 through > 135.8 > 6 We hope to start 2000Z fri and run til 0700 both nights. > 7 after contact has been established. We will look for 10 second dot > qrss > 8 I hope to have email > 9 please pass this info to MM0ALM. > > Yes I would like phone numbers including G0MRF AND OK1FIG at > remote sites and MM0ALM if available > 73 all and pray for benign weather. de John VE1ZJ > > Mike Dennison wrote: > > > This weekend, there is the greatest opportunity yet to make the > > transatlantic two-way. > > > > I would like to suggest some procedures to maximise that > > opportunity and minimise mutual QRM. Please feel free to point out > > any flaws in my argument. > > > > As far as possible, continuous beaconing should be avoided, > > especially if another station is operating near to you. > > > > Transmission slots to be 15 minutes: VE1ZZ transmits from 00 and > > 30 minutes past the hour, Eu stations transmit from 15 and 45 > > minutes past the hour. Send just your own callsign and wait for Jack > > to identify you. If a QSO happens, all other stations to stop > > transmitting. > > > > There is a frequency plan at http:www.lf.thersgb.net/transatlantic.htm > > using the sub-band 135.9-136.0kHz. This includes the Loran > > frequencies for the Canadian end. It is intended for guidance only, > > but it will probably help the chances of success if we make an effort > > to avoid each other. It will also help John/Jack/Larry and the > > AMRAD team to know which frequency to find what station. Please > > e-mail me any updates. > > > > If it helps, I can post telephone numbers on that web page, too (they > > can be removed after the event). > > > > I will post a separate message reminding QRSS novices of > > procedures. > > > > Good luck! > > > > Mike, G3XDV (IO91VT) > > http://www.lf.thersgb.net From ryeg at sitestar.net Thu Jan 11 05:31:04 2001 From: ryeg at sitestar.net (Rye Gewalt) Date: Thu Jul 3 13:43:28 2003 Subject: [Lf] This week end at Burk Lake References: <3A5BCC7D.101A68F0@bellatlantic.net> Message-ID: <3A5D8B68.ACA2F71C@sitestar.net> Yes! I'd like to join your Merry Band of Midnight Marauders. I can contribute: A 30(?) foot portable vertical (pre WWII tactical army kit) Several big fully charged marine wet cell lead acid DD batteries My ODC100 active antenna An AOR 3030 receiver that I'd like to try A couple of credit card 440 Alinco HTs A Coleman gas catalytic heater A strong back and a weak mind. I've been thinking about the parks for a while now since I live very near Lake Accotink and there is a high abutment above the dam with a 400' cable running in the water across the dam that would make a dandy ground counterpoise. I'll have to check with them one of these days. I know that they have a full time night watchman who's usually pretty laid back and the park manager is a nice lady..... Gosh, just like field day only colder. Regards Rye K9LCJ 703 451-7352 Andre' Kesteloot wrote: > Gang, > I have obtained authorization from the Fairfax Park > Authority for AMRAD members to deploy LF receiving equipment > at Burke Lake Park (on Rt. 123, near Lorton) this Saturday > 13 and Sunday 14 January, both evenings from 1800 till > midnight. > > Are there any volunteers to accompany me either night? > > Let's discuss this subject on Thursday evening, at the > monthly AMRAD meeting. > hanks in advance. > Andre' N4ICK > > _______________________________________________ > lf mailing list > lf@amrad.org > http://www.amrad.org/mailman/listinfo/lf -------------- next part -------------- An HTML attachment was scrubbed... URL: http://atanasoff.rf.org/pipermail/lf/attachments/20010111/5dfd5d3e/attachment.html From akestelo at bellatlantic.net Thu Jan 11 08:33:03 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:29 2003 Subject: [Lf] Transatlantic tests January 12th Message-ID: <3A5DB60F.9DC19CA2@bellatlantic.net> Petr Maly wrote: > Hi Andre About the tests, I posted brief info > to:http://www.lwca.org/wwwboard/wwwboard.html The main aim > is to reach 2-way QRSS QSO on 136 kHz over the Atlantic > (with John VE1ZJ and Jack VE1ZZ).I guess this info is > known to you, Mike G3XDV advised me to write an e-mail to > you for sure. Mind that I will have 150 meters hight > T-antenna and PA about 600 watts, it means that ERP will > be several hundreds watts, which is in avarage 1000 times > more that the other Eu stations... Looking forward to your > reports. reply to OK1FIG@volny.cz 73 Petr OK1FIG -------------- next part -------------- An HTML attachment was scrubbed... URL: http://atanasoff.rf.org/pipermail/lf/attachments/20010111/703601ac/attachment.html From akestelo at bellatlantic.net Thu Jan 11 08:33:03 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:29 2003 Subject: [Lf] Transatlantic tests January 12th Message-ID: <3A5DB60F.9DC19CA2@bellatlantic.net> Petr Maly wrote: > Hi Andre About the tests, I posted brief info > to:http://www.lwca.org/wwwboard/wwwboard.html The main aim > is to reach 2-way QRSS QSO on 136 kHz over the Atlantic > (with John VE1ZJ and Jack VE1ZZ).I guess this info is > known to you, Mike G3XDV advised me to write an e-mail to > you for sure. Mind that I will have 150 meters hight > T-antenna and PA about 600 watts, it means that ERP will > be several hundreds watts, which is in avarage 1000 times > more that the other Eu stations... Looking forward to your > reports. reply to OK1FIG@volny.cz 73 Petr OK1FIG -------------- next part -------------- An HTML attachment was scrubbed... URL: http://atanasoff.rf.org/pipermail/lf/attachments/20010111/703601ac/attachment-0001.html From akestelo at bellatlantic.net Thu Jan 11 08:32:00 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:29 2003 Subject: [Lf] qrss dot length Message-ID: <3A5DB5D0.7C20F74A@bellatlantic.net> Rik Strobbe wrote: > At 02:31 11/01/01 -0000, WD4KPD wrote: > >good day all....anyone know how dot length translates to WPM ? > >i have seen some QRSS speeds listed in WPM on the net especially concerning > >lowfer/medfer beacons in USA. > > WPM (Words Per Minute) is based on the 'PARIS' system, where PARIS is taken > as a standard word that has a length of exactly 50 dots (including word > spacing). > As a result 1 WPM = 50 dots per minute , 12 WPM = 600 dots per minute and > so on ... > Or the other way arround at 1 WPM a dot takes 60/50 = 1.2 seconds, at 12 > WPM a dot is 0.1 second long. > > So : dot length (seconds) = 1.2/WPM > > 73, Rik ON7YD From akestelo at bellatlantic.net Thu Jan 11 08:25:54 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:29 2003 Subject: [Lf] [Fwd: LF: Weekend tests] Message-ID: <3A5DB462.C0413CD4@bellatlantic.net> Mike Dennison wrote: > In the enthusiasm to make the first transatlantic 2-way QSO, it is > easy to ignore other useful things that can happen this weekend. > > Firstly, AMRAD will be doing receive tests from the North Carolina > coast, and this extends to Sunday night / Monday morning (Eu > time). They will want some Eu signals to listen/look for, even after > John and Jack have finished. > > Secondly, it would be really useful for other Eu stations to make > comparisons of the signals they hear/see. I have found it very > helpful to see how my signal compares with others on a spectrogram. > > Thirdly, this is a good opportunity for various Eu stations to record > how they receive VE1ZZ at what times, so we can see how > propagation varies. > > Lastly, there is still time for someone to record (preferably as a > computer audio file) the first normal speed CW from VE. > > This should keep many stations busy whilst the really big guys try > the two-way. > > Have fun. > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From akestelo at bellatlantic.net Thu Jan 11 08:31:21 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:29 2003 Subject: [Lf] Rugby Loading Coils Message-ID: <3A5DB5A9.4B2B7840@bellatlantic.net> James Moritz wrote: > Dear LF Group, > > Alan makes reference to the loading coils at the 16kHz VLF station > at Rugby; A while ago I got hold of a couple of old papers detailing > the original construction of the VLF stations at Rugby (1925) and > Criggion (1943). > > The loading coils for both stations were wound as spirals on five > hexagonal wooden spiders, roughly 4m diameter. The spiders could > be moved to vary the inductance, which was about 2.5mH for > Rugby, and 5.4mH for Criggion. The wood is described as > "American whitewood", which the Post Office engineers apparently > found was a highly satisfactory material; no other insulation for the > windings was used. The antenna voltage and current was 220kV, > 400A at Criggion, and 160kV, 600A at Rugby. The windings were > (HF) litz wire made up from 6561 strands of 36swg. The Q was in > the range 2000 to 4000. The Rugby transmitter building was > designed to minimise the amount of metal, etc. close to the loading > coils, while at Criggion, the loading coil was inside a reinforced > concrete building. This caused high losses until a Faraday shield > was installed by lining the walls with a mesh of copper wires. The > Rugby transmitter building burned down in 1943, so we are not the > only ones with these problems! > > Both these stations are still there (obviously modernised a bit), and > worth a look if you are passing by. Rugby is by the side of the A5, > and Criggion is on the Welsh borders a few miles east of > Welshpool. The road to Criggion village actually passes under the > VLF antenna, so you get a good view there. > > It is interesting to read the discussion at the end of the Rugby > paper - some audience members state that the VLF station had > effectively been rendered obsolete by the HF beam systems then > coming into being - yet, 75 years later, GBR is still there on 16kHz, > and it is the HF systems that have disappeared! > > Cheers, Jim Moritz > 73 de M0BMU From akestelo at bellatlantic.net Thu Jan 11 08:30:00 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:30 2003 Subject: [Lf] This week end: ERP of several hundred watts... Message-ID: <3A5DB558.E83E8AC2@bellatlantic.net> OK Petr, don't worry, we shall be looking for you too ! 73 Andre' N4ICK Petr Maly wrote: > Hi Andre About the tests, I posted brief info > to:http://www.lwca.org/wwwboard/wwwboard.html The main aim > is to reach 2-way QRSS QSO on 136 kHz over the Atlantic > (with John VE1ZJ and Jack VE1ZZ).I guess this info is > known to you, Mike G3XDV advised me to write an e-mail to > you for sure. Mind that I will have 150 meters hight > T-antenna and PA about 600 watts, it means that ERP will > be several hundreds watts, which is in avarage 1000 times > more that the other Eu stations... Looking forward to your > reports. reply to OK1FIG@volny.cz 73 Petr OK1FIG -------------- next part -------------- An HTML attachment was scrubbed... URL: http://atanasoff.rf.org/pipermail/lf/attachments/20010111/22b68e89/attachment.html From akestelo at bellatlantic.net Thu Jan 11 08:27:20 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:30 2003 Subject: [Lf] This week end at Burk Lake References: <3A5BCC7D.101A68F0@bellatlantic.net> <3A5D8B68.ACA2F71C@sitestar.net> Message-ID: <3A5DB4B7.46264D32@bellatlantic.net> Would Accotink be a better place than Burke Lake Park ? Can we still obtain permission to go there ? Andre' N4ICK Rye Gewalt wrote: > Yes! I'd like to join your Merry Band of Midnight > Marauders. I can contribute: > > A 30(?) foot portable vertical (pre WWII > tactical army kit) > Several big fully charged marine wet cell lead > acid DD batteries > My ODC100 active antenna > An AOR 3030 receiver that I'd like to try > A couple of credit card 440 Alinco HTs > A Coleman gas catalytic heater > A strong back and a weak mind. > > I've been thinking about the parks for a while now since I > live very near Lake Accotink and there is a high abutment > above the dam with a 400' cable running in the water > across the dam that would make a dandy ground > counterpoise. I'll have to check with them one of these > days. I know that they have a full time night watchman > who's usually pretty laid back and the park manager is a > nice lady..... > > Gosh, just like field day only colder. > > Regards > Rye K9LCJ > 703 451-7352 > > > > > > > > > > > > Andre' Kesteloot wrote: > >> Gang, >> I have obtained authorization from the Fairfax Park >> Authority for AMRAD members to deploy LF receiving >> equipment >> at Burke Lake Park (on Rt. 123, near Lorton) this >> Saturday >> 13 and Sunday 14 January, both evenings from 1800 till >> midnight. >> >> Are there any volunteers to accompany me either night? >> >> Let's discuss this subject on Thursday evening, at the >> monthly AMRAD meeting. >> hanks in advance. >> Andre' N4ICK >> >> _______________________________________________ >> lf mailing list >> lf@amrad.org >> http://www.amrad.org/mailman/listinfo/lf > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://atanasoff.rf.org/pipermail/lf/attachments/20010111/20038bc9/attachment.html From akestelo at bellatlantic.net Thu Jan 11 19:15:15 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:30 2003 Subject: [Lf] Home Brew PSK31] Message-ID: <3A5E4C93.385305FC@bellatlantic.net> Graeme Zimmer wrote: > Hi Folks.... > > I've just uploaded details of my little PSK31 audio Transmitter > > http://www.users.bigpond.com/gzimmer/default.html > > cheers ............... Zim ................ VK3GJZ From akestelo at bellatlantic.net Fri Jan 12 09:14:14 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:31 2003 Subject: [Lf] Rugby site] Message-ID: <3A5F1136.1168DB05@bellatlantic.net> Talbot Andrew wrote: > Allegedly and without predjudice, as long as certain people want to > exist safely underneath the sea, Rugby and Criggion will remain. The > phase stabilisation Alan mentions allows, amongst other things, the > remote monitoring of transmitter health from remote sites . Who said > that ?! :-|| > > According to Tom Clancy, in "The Hunt for Red October" there is a > transmission of coded groups to very deep operating "Boomers" at a data > rate that appears to be in the region of a bit per second (one minute > per message). The groups would encode messages such as "Come to the > surface immediately for a satellite transmission", or "Fire !". If it is > not all a fiction invented by an author with a large collection of > friends working at interesting places. Speculatively of course, this > would be at a frequency in the 60 - 170Hz region - which makes even > amateur 9kHz experiments seem tame. It is stated that in the US there > are lines looking like old fashioned telegraph wires many hundreds > (1000s ?) of km long carrying signals that make fences spark. > > At these frequencies a ground loop antenna is the only realistic sort of > antenna that could be made to operate with reasonable efficiency and > long low slung wires which wouldn't have to even be grounded at the far > end if long enough would form just such an antenna - Some people have > suggested - and this is no sxcrxt - that the UK tried some propagation > tests at ULF (Ultra Low Frequency, 30 - 300Hz or shold this be SLF) in > the 1960s, but decided we didn't need the deep operations around the > world this would allow. I was told once (by someone long retired from > the business) that there were ideas to use the third rail of the > railway network to form the antenna for a ULF transmission, others > proposed the National Grid but the idea of a multiplexer to separate > 50Hz from the transmitting freq (at say 100 Hz) would be 'interesting' > > Anon G^JN* > > > If anyone can arrange a visit to Rugby Radio Station before > > it all goes the > > same way I am sure there would be plenty of takers. > > > > Cheers de Alan G3NYK > > > > -- > The Information contained in this E-Mail and any subsequent correspondence > is private and is intended solely for the intended recipient(s). > For those other than the recipient any disclosure, copying, distribution, > or any action taken or omitted to be taken in reliance on such information is > prohibited and may be unlawful. From akestelo at bellatlantic.net Fri Jan 12 09:15:54 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:31 2003 Subject: [Lf] Russian 82 Hz (!) Tx system Message-ID: <3A5F1199.CAE2F0AB@bellatlantic.net> Alberto di Bene wrote: > For a comprehensive page on the ELF russian submarine communications > system ZEVS at 82 Hz (!) look here : > http://web.tiscalinet.it/vlfradio/zevs/zevs.htm > > 73 Alberto I2PHD From fgentges at mindspring.com Sat Jan 13 05:52:37 2001 From: fgentges at mindspring.com (Frank Gentges K0BRA) Date: Thu Jul 3 13:43:31 2003 Subject: [Lf] Nags Head Progress Report Message-ID: <001f01c07d25$0948c5c0$113479a5@mercury> Hi, We set up tonight here to listen to LF. The noise levels are low and we got 2 good setups with notebooks running ARGO and SPECTRAN. Loran artifacts can be heard but they are under control. The new active antenna is working fine business. Copied LOWFer DCH from Berlin MD and VE1ZZ was coming in all evening usually copyable aurally as well as visually. We watched for OK1 station but did not see anything. We also monitored 135.900 -135.980 and did not see anything there either. We plan to try some other things in tomorrow's daylight. We set up tonight in the dark and are not sure what we will see in the daylight. Weather is not too cold and just a few spits of rain. We are anxious to try to see Dave, G3LDO's signal tomorrow night. Everything will be tuned as best we can for that time period. Frank Gentges, K0BRA ex AK4R, W3FGL Sandy, WB5MMB For the latest on LF See http://www.amrad.org/projects/lf From fgentges at mindspring.com Sun Jan 14 05:12:15 2001 From: fgentges at mindspring.com (Frank Gentges K0BRA) Date: Thu Jul 3 13:43:31 2003 Subject: [Lf] Nags Head SITREP 14 Jan Message-ID: <001101c07de8$900b05a0$5c3079a5@mercury> We are closing up for Saturday night. Propagation to Europe is poor. LW Bcst signals weak and lousy. The propagation to somewhere they are having thunderstorms seems pretty good. We will try some more tomorrow. LOWFers may be heard then so we will concentrate on them. On a good note we were able to receive VE1ZZ most of the night above the static. It has been a bit of a beacon to judge things with. Frank Gentges K0BRA ex AK4R, W3FGL For the latest on LF See http://www.amrad.org/projects/lf From akestelo at bellatlantic.net Sun Jan 14 09:24:49 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:31 2003 Subject: [Lf] Nags Head SITREP 14 Jan References: <001101c07de8$900b05a0$5c3079a5@mercury> Message-ID: <3A61B6B1.A1888FA8@bellatlantic.net> Although we had an excellent location at Burke Lake Park, and we could hear the Indian Submarine station on 18.5 KHZ, WWVB on 60 KHz, DCF39 (very faint and a few NDB beacons, we heard or saw nothing on the 136 KHz band, between 1800h and 2400h local time (EST). We could not even hear the French broadcast stations on LF (Allouis, Europe#1, or Luxembourg on 234) Plenty of statics, though :-) Details (and photographs) of our expedition to follow on the AMRAD Web page 73 Andre' N4ICK ****************************************** Frank Gentges K0BRA wrote: > We are closing up for Saturday night. Propagation to Europe is poor. LW > Bcst signals weak and lousy. The propagation to somewhere they are having > thunderstorms seems pretty good. We will try some more tomorrow. LOWFers > may be heard then so we will concentrate on them. > > On a good note we were able to receive VE1ZZ most of the night above the > static. It has been a bit of a beacon to judge things with. > > Frank Gentges > K0BRA ex AK4R, W3FGL > For the latest on LF See http://www.amrad.org/projects/lf > > _______________________________________________ > lf mailing list > lf@amrad.org > http://www.amrad.org/mailman/listinfo/lf From akestelo at bellatlantic.net Sun Jan 14 09:31:49 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:31 2003 Subject: [Lf] [Fwd: LF: Achievements] Message-ID: <3A61B855.C3B4B856@bellatlantic.net> "mike.dennison" wrote: > My experience last night was the same as others: S9+20dB QRN and a high > white noise level. From 2200 to 0300 I saw only vague traces of signals from > VE, and no Morse characters at all. Transmitted 3s dots before 0300 and 10s > afterwards. Went to bed at 0330. > > A big shame for G0MRF who chose the wrong day. I am sure he could have made > the two-way on Saturday morning. > > However, although the two-way was not achieved, the weekend was not a > failure. The one-way record has been broken in both directions, another > Canadian has been heard across the pond, VE1ZZ has been able to see for > himself the benefits of QRSS, and I am sure that many of us have used these > tests to make improvements to our stations. And of course the interest > generated by the OK1FIG expedition (judging by the very many crossband QSOs > he was having to 7MHz) will have encouraged more to come on LF. > > Thanks to John, Jack and Larry, and the guys from AMRAD, for concentrating > the activity at their end. > > Is there anyone listening tonight, or can I go to bed early? > > Mike, G3XDV From riese-k3djc at juno.com Sun Jan 14 11:01:39 2001 From: riese-k3djc at juno.com (robert c riese) Date: Thu Jul 3 13:43:32 2003 Subject: [Lf] Nags Head SITREP 14 Jan Message-ID: <20010114.110159.-13407.1.riese-k3djc@juno.com> Found the same cdx inland as well. WA3USG and I did a bit of plotting and in my opinion ZZ was as weak as we have ever seen him TUK was readable but no where as strong as it can be, mostly chatted on 144 Bob On Sun, 14 Jan 2001 09:24:49 -0500 "Andre' Kesteloot" writes: > > >Although we had an excellent location at Burke Lake Park, >and we could hear the >Indian Submarine station on 18.5 KHZ, WWVB on 60 KHz, DCF39 >(very faint and a few NDB beacons, we >heard or saw nothing on the 136 KHz band, between 1800h and >2400h local time >(EST). >We could not even hear the French broadcast stations on LF >(Allouis, Europe#1, or Luxembourg on 234) >Plenty of statics, though :-) >Details (and photographs) of our expedition to follow on the >AMRAD Web >page >73 >Andre' N4ICK >****************************************** >Frank Gentges K0BRA wrote: > >> We are closing up for Saturday night. Propagation to Europe is >poor. LW > From akestelo at bellatlantic.net Sun Jan 14 13:44:16 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:32 2003 Subject: [Lf] AMRAD team #2 Message-ID: <3A61F37F.1FDF6622@bellatlantic.net> Hello Gang, AMRAD Listening Team #1 (that was deployed yesterday --Saturday-- until 0500 GMT near Washington DC) will not be listening tonight (Sunday) but Frank K0BRA and AMRAD Listening Team #2 (located at Nags Head, North Carolina) will be listening for signal from Europe and Canada. Best regards Andre' N4ICK -------------- next part -------------- An embedded message was scrubbed... From: "Frank Gentges K0BRA" Subject: Re: [Lf] [Fwd: LF: Achievements] Date: Sun, 14 Jan 2001 16:07:45 -0000 Size: 3135 Url: http://atanasoff.rf.org/pipermail/lf/attachments/20010114/357a5162/attachment.txt From akestelo at bellatlantic.net Sun Jan 14 13:49:38 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:32 2003 Subject: [Lf] [Fwd: LF: Achievements] Message-ID: <3A61F4C2.F5E9E306@bellatlantic.net> "mike.dennison" wrote: > My experience last night was the same as others: S9+20dB QRN and a high > white noise level. From 2200 to 0300 I saw only vague traces of signals from > VE, and no Morse characters at all. Transmitted 3s dots before 0300 and 10s > afterwards. Went to bed at 0330. > > A big shame for G0MRF who chose the wrong day. I am sure he could have made > the two-way on Saturday morning. > > However, although the two-way was not achieved, the weekend was not a > failure. The one-way record has been broken in both directions, another > Canadian has been heard across the pond, VE1ZZ has been able to see for > himself the benefits of QRSS, and I am sure that many of us have used these > tests to make improvements to our stations. And of course the interest > generated by the OK1FIG expedition (judging by the very many crossband QSOs > he was having to 7MHz) will have encouraged more to come on LF. > > Thanks to John, Jack and Larry, and the guys from AMRAD, for concentrating > the activity at their end. > > Is there anyone listening tonight, or can I go to bed early? > > Mike, G3XDV From fgentges at mindspring.com Mon Jan 15 04:45:10 2001 From: fgentges at mindspring.com (Frank Gentges K0BRA) Date: Thu Jul 3 13:43:32 2003 Subject: [Lf] Team #2 Nags Head Sitrep 15 Jan Message-ID: <002501c07ead$f6be9120$033479a5@mercury> We had much lower noise levels and better propagation tonight. We copied VE1ZZ all evening and at some times aurally. We monitored the European/NA band all evening but did not see anything. We made a day trip down to Hatteris Lighthouse and setup our new active antenna. We did not see intermods from the Loran C transmitter at Carolina Beach. The active antenna passed an acid test to be placed in the teeth of the Loran C like this. It help demonstrate also how clean the Loran C transmitter is. I think it is time to freeze the design and let the rest of you start building a few. I will be sending the details off to get the PC boards made now. Stay tuned to the AMRAD newsletter for assembly instructions. We will listen for a few minutes in the morning and then will begin packing up for the trip back to Washington. It was a good trip this year. We got to see a lot of pieces integrated together better than before. Now if we can just get an extra special propagation night. Frank Gentges K0BRA ex AK4R, W3FGL For the latest on LF See http://www.amrad.org/projects/lf From akestelo at bellatlantic.net Mon Jan 15 09:14:59 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:33 2003 Subject: [Lf] Microsoft Whistler Message-ID: <3A6305E3.361A4C@bellatlantic.net> It seems that one would be well advised to think twice before upgrading Microsoft products as both Office SR1/2 and now the entire operating system (Whistler) is in the enforced mode of "you can only use it on one computer and you need our permission online". The security and privacy implications are not trivial. Not to mention the hassle everytime one needs to reinstall software (due to a crash or HD change or when buying a replacement computer). Microsoft seems hell bent upon cash-maximization. Andre' N4ICK http://www.windows-help.net/Newsletter/13jan2001.html From akestelo at bellatlantic.net Mon Jan 15 17:46:36 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:33 2003 Subject: [Lf] [Fwd: LF: Report on weekend] Message-ID: <3A637DCC.56B9161E@bellatlantic.net> "mike.dennison" wrote: > I have posted on my website a summary of reports from this group about the > weekend's tests. This will form a record of the experiment. The page is: > http://www.lf.thersgb.net/test010112.htm > > Mike, G3XDV From ryeg at sitestar.net Wed Jan 17 17:49:08 2001 From: ryeg at sitestar.net (Rye Gewalt) Date: Thu Jul 3 13:43:33 2003 Subject: [Lf] Selective Voltmeter Message-ID: <3A662164.27516087@sitestar.net> I don't know if anybody might be interested but there a couple of Rycom Selective Voltmeters on EBay one with a starting bid price of $1 and no bids. From akestelo at bellatlantic.net Thu Jan 18 17:27:18 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:33 2003 Subject: [Lf] [Fwd: LF: Dipole antenna at LF] Message-ID: <3A676DC6.EE79223C@bellatlantic.net> Thais the kind of installation we have in Front-Royal... Andre' N4ICK ************************************** Larry Kayser wrote: > > Many years ago I did read somwhere an article about > > horizontal dipoles used in the desert that were just laying on the sand. > > I hope this relates, but we used to lay MF and HF antennas on the surface of > the snow or even ice in the Canadian Arctic. When we started it was a big > deal to use some poles about 5 or 6 ft long to support the antennas, then we > noticed it did not mater (when they fell down) so we just let the wire lay > on the surface. > > Larry > VA3LK From akestelo at bellatlantic.net Thu Jan 18 17:31:46 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:34 2003 Subject: [Lf] Skywave and LF Message-ID: <3A676ED1.4AD8A652@bellatlantic.net> WarmSpgs@aol.com wrote: > In a message dated 1/18/01 6:22:22 AM Eastern Standard Time, > ACTALBOT@dera.gov.uk writes: > > << To me, the idea of being able to actually see > ionospheric effects on skywave signals at LF, which to my knowledge have > never before been characterised, is more exciting than being the first > to make a two way QSO. Previously, as Walter said, skywave was just a > nuisance that they tried to eliminate. >> > > Not so! The IRE Proceedings and other literature of the 1920s and 30s were > replete with studies characterizing skywave propagation on LF, as it was > realized very early on that skywave is both the dominant DX mode at night and > a factor that must be accounted for in the daytime. More of a daytime factor > than MF, actually, and not one which could be dealt with as easily on LF by > building ever-taller towers. > > This is one of those cases where we _are_ re-inventing the wheel--and yet, I > believe it is still worth doing. Most of us no longer have access to the > older data; and it was generated using much higher power levels, which could > potentially obscure interesting effects that we might be able to exploit. > > 73, > John From akestelo at bellatlantic.net Thu Jan 18 23:04:10 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:34 2003 Subject: [Lf] RSGB LF Handbook update] Message-ID: <3A67BCBA.DCEF8788@bellatlantic.net> g3ldo wrote: > I have posted an Addendum and Errata to The Low Frequency > Experimenter's Handbook at > http://web.ukonline.co.uk/g3ldo/ . This information will > shortly be included in the Book Shop of the RSGB web > site. At the last meeting at Windsor several of our group > felt that it would be useful if some of the technical > subjects discussed over this LF reflector might be > collated and made into an indexed document (web page?). I > would be happy to do this if this is what you would like > to see. I have LF e-mails on file that go back to the time > the LF reflector was created.Please note that my e-mail > address is now g3ldo@ukonline.co.uk Regards, > Peter, G3LDO -------------- next part -------------- An HTML attachment was scrubbed... URL: http://atanasoff.rf.org/pipermail/lf/attachments/20010118/2cc22fe3/attachment.html From akestelo at bellatlantic.net Sat Jan 20 09:34:13 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:35 2003 Subject: [Lf] LF: NASA recordings of ELF sounds.] Message-ID: <3A69A1E4.5A3F648E@bellatlantic.net> john sexton wrote: > Hi All, > Thought this might be of interest to Lowfers. > > From: "NASA Science News" > Subject:Earth Songs > NASA Science News for January 19, 2001 > > If humans had radio antennas instead of ears, we would hear a remarkable > symphony of strange noises coming from our own planet. An online receiver at > the Marshall Space Flight Center is playing > these songs of Earth so anyone can listen. > > FULL STORY at > > http://science.nasa.gov/headlines/y2001/ast19jan_1.htm?list43215 > --- > John, G4CNN > > _______________________________________________________ > Send a cool gift with your E-Card > http://www.bluemountain.com/giftcenter/ From akestelo at bellatlantic.net Sat Jan 20 15:50:17 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:35 2003 Subject: [Lf] Experimentations... Message-ID: <3A69FA09.8B9988A6@bellatlantic.net> Talbot Andrew wrote: > Peter - et al > > For some of us scientific experiements and measurement / understanding > of the propagation medium is of far greater interest than merely trying > to make QSOs. To me, the idea of being able to actually see > ionospheric effects on skywave signals at LF, which to my knowledge have > never before been characterised, is more exciting than being the first > to make a two way QSO. Previously, as Walter said, skywave was just a > nuisance that they tried to eliminate. > > If two operators at each end happen to be awake and operating at the > right time that an ionospheric bubble forms (or whatever is up there) > with a high power transmitter and big antenna, then they'll make the > QSO. But no one will know the mechanism by which the QSO was achieved, > apart from brute force, until it has happened several times and been > mapped out. > Meanwhile we will continue with proper controlled scientific experiments > at low powers where Larry's signal appears to be receivable 100% of the > time. Then with the knowledge we can attack the medium in a controlled > way. > > Anyone can join in if they have suitable receiving hardware - all it > wants is a willingness to build and understand new and modern hardware; > a quality sadly lacking in many of today's radio amateurs. > Particularly unfortunate as there is a huge range of devices that make > homebrewing of quite advanced equipment trivial - and finding the > necessary data is not even the trial it once was, everything is > available on line. > > Andy G4JNT > > > > -----Original Message----- > > From: g3ldo [mailto:g3ldo@ukonline.co.uk] > > Sent: 2001-01-18 10:14 > > To: rsgb_lf_group@blacksheep.org > > Subject: Re: LF: Transmitting tests on 137.790 > > > > > > they will never find out.> > Time is however of the essence and I > have not yet heard a > > European signal > > across the North Atlantic ......... > > > > Quite a few LF trains have departed EU, bound for VE. Some caught > them, some > > did not. > You need the right (mode) ticket. > > > > Regards, > > Peter, G3LDO > > > > > > -- > The Information contained in this E-Mail and any subsequent correspondence > is private and is intended solely for the intended recipient(s). > For those other than the recipient any disclosure, copying, distribution, > or any action taken or omitted to be taken in reliance on such information is > prohibited and may be unlawful. From akestelo at bellatlantic.net Sun Jan 21 10:01:41 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:35 2003 Subject: [Lf] Buzz words Message-ID: <3A6AF9D5.3E7D8E8C@bellatlantic.net> What we really need to design, at AMRAD, is simply an asynchronous, robust, real-time, object-oriented, fault-tolerant, multimedia, platform independent, client/server, multitasking seamless solution to the problem Andre' N4ICK From fgentges at mindspring.com Sun Jan 21 11:51:42 2001 From: fgentges at mindspring.com (Frank Gentges =?iso-8859-1?Q?K=D8BRA?=) Date: Thu Jul 3 13:43:35 2003 Subject: [Lf] Re: Buzz words In-Reply-To: <3A6AF9D5.3E7D8E8C@bellatlantic.net> Message-ID: <5.0.2.1.0.20010121114131.00a5f670@pop.mindspring.com> My preference would be for a fully synchronous, frangible, post facto, assembly language, easily reparable single thread system focused on a single media single platform low cost, highly proliferable, specific solution to our problem that has clearly defined boundaries. Frank K0BRA At 10:01 AM 1/21/01 -0500, you wrote: >What we really need to design, at AMRAD, >is simply an asynchronous, robust, real-time, >object-oriented, >fault-tolerant, multimedia, platform independent, >client/server, multitasking seamless solution to the problem >Andre' N4ICK > > >_______________________________________________ >Tacos mailing list >Tacos@amrad.org >http://www.amrad.org/mailman/listinfo/tacos From riese-k3djc at juno.com Sun Jan 21 12:16:28 2001 From: riese-k3djc at juno.com (BOB RIESE) Date: Thu Jul 3 13:43:36 2003 Subject: [Lf] Buzz words Message-ID: <20010121.122130.-165251.0.riese-k3djc@juno.com> you betcha Bob On Sun, 21 Jan 2001 10:01:41 -0500 "Andre' Kesteloot" writes: > > >What we really need to design, at AMRAD, >is simply an asynchronous, robust, real-time, >object-oriented, >fault-tolerant, multimedia, platform independent, >client/server, multitasking seamless solution to the problem >Andre' N4ICK > > >_______________________________________________ >lf mailing list >lf@amrad.org >http://www.amrad.org/mailman/listinfo/lf From ryeg at sitestar.net Sun Jan 21 19:47:29 2001 From: ryeg at sitestar.net (Rye Gewalt) Date: Thu Jul 3 13:43:36 2003 Subject: [Lf] Re: Buzz words References: <5.0.2.1.0.20010121114131.00a5f670@pop.mindspring.com> Message-ID: <3A6B8321.EE12DD34@sitestar.net> ......and it must have long term functional mobility. Rye Frank Gentges K?BRA wrote: > My preference would be for a fully synchronous, frangible, post facto, > assembly language, easily reparable single thread system focused on a > single media single platform low cost, highly proliferable, specific > solution to our problem that has clearly defined boundaries. > > Frank K0BRA > > At 10:01 AM 1/21/01 -0500, you wrote: > >What we really need to design, at AMRAD, > >is simply an asynchronous, robust, real-time, > >object-oriented, > >fault-tolerant, multimedia, platform independent, > >client/server, multitasking seamless solution to the problem > >Andre' N4ICK > > > > > >_______________________________________________ > >Tacos mailing list > >Tacos@amrad.org > >http://www.amrad.org/mailman/listinfo/tacos > > _______________________________________________ > lf mailing list > lf@amrad.org > http://www.amrad.org/mailman/listinfo/lf From akestelo at bellatlantic.net Sun Jan 21 20:31:22 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:36 2003 Subject: [Lf] Re: Buzz words References: <5.0.2.1.0.20010121114131.00a5f670@pop.mindspring.com> <3A6B8321.EE12DD34@sitestar.net> Message-ID: <3A6B8D6A.E1938FA9@bellatlantic.net> I like that one ... Andre' Rye Gewalt wrote: > ......and it must have long term functional mobility. > > Rye > > Frank Gentges K?BRA wrote: > > > My preference would be for a fully synchronous, frangible, post facto, > > assembly language, easily reparable single thread system focused on a > > single media single platform low cost, highly proliferable, specific > > solution to our problem that has clearly defined boundaries. > > > > Frank K0BRA > > > > At 10:01 AM 1/21/01 -0500, you wrote: > > >What we really need to design, at AMRAD, > > >is simply an asynchronous, robust, real-time, > > >object-oriented, > > >fault-tolerant, multimedia, platform independent, > > >client/server, multitasking seamless solution to the problem > > >Andre' N4ICK > > > > > > > > >_______________________________________________ > > >Tacos mailing list > > >Tacos@amrad.org > > >http://www.amrad.org/mailman/listinfo/tacos > > > > _______________________________________________ > > lf mailing list > > lf@amrad.org > > http://www.amrad.org/mailman/listinfo/lf From akestelo at bellatlantic.net Mon Jan 22 17:50:58 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:36 2003 Subject: [Lf] WWVB Doing testing in the field] Message-ID: <3A6CB951.93C185E2@bellatlantic.net> "Paul A. Cianciolo" wrote: > Hello Folks, > > After seeing WWVB signal stay constant quite a while. I decided to give > them a call. > They said they are performing field stregth tests and needed the constant > carrier for accurate measurements. Also that the testing wil continue for > a couple of weeks. > I asked if they were goingto put a schedule up on the outage page at there > site, and they said there would be. Threre is nothing there about right > now. > > Maybe this clears up Johns question about there signal level > > http://www.bldrdoc.gov/timefreq/stations/wwvb.htm > Paulc > W1VLF From akestelo at bellatlantic.net Mon Jan 22 17:43:08 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:37 2003 Subject: [Lf] [Fwd: LF: Frequency Calibration Argo etc.] Message-ID: <3A6CB77C.17B12451@bellatlantic.net> Talbot Andrew wrote: > The recent talk about soundcard accuracies set me thinking. Tuning > error and soundcard accuracy do not have exactly the same effect on the > apparent observed frequency line in Argo or any DSP system where the > sampling rate is not locked to the same frequency as used for tuning. > > Tuning error is reflected as a frequency shift which applies equally to > all tones within an audio bandwidth. > Sampling rate error appears to change the tones by an amount > proportional to frequency. > > eg at 8000 Hz sampling rate + 10ppm = 8000.08 Hz > a 1kHz tone will appear at to be 999.99Hz (0.01 Hz low), 1500Hz will > appear to be 1499.985Hz (0.015Hz low) etc > If the receiver tuning is 0.1 Hz in error these would be 999.9 ands > 1499.9 respectively. > > So to calibrate out both uncertainties a minimum of two measurements are > needed. Here is a procedure to do this : > > Tune into a transmission whose frequency is known EXACTLY - such as MSF > at 60kHz or the centre of Loran at 100kHz - using your favourite piece > of narrow band software and receiver as used normally. Adjust tuning > for an audio tone of 500Hz and measure the exact tone frequency > resulting. Then alter the receiver tuning to get a tone of 2500Hz > and measure this figure exactly. > > The difference between the two measured frequencies expressed as a > fraction of the wanted separation (here 2kHz) is the soundcard sampling > error rate. Any error that applies equally to both tones is due to > receiver tuning alone. Obviously the widest tone separation as possible > is desired to minimise measurement error. > This test does pre-suppose that the error in the receiver is determined > only by its internal oscillators and not by errors in transferring the > desired frequency to the display. Most modern PLL and DDS controlled > receivers do in fact generate exactly what the dial says, subject only > to their oscillator calibration. > > In most cases the receiver frequency setting error should swamp that of > the soundcard but this may always not necessarily be the case. For > example an IC746 with TCXO option and trimmed to 0.2ppm accuracy (it can > be done) used to receive directly on 137kHz will exhibit an error of > 0.027 Hz as all frequencies within the reciver are locked to the master > source. A laptop integral soundcard could easily be 30ppm out even if > the oscillator is 'meant' to be exact ie. not allowing for poor > implementation which can give errors up to 0.2 percent !!! 30ppm would > give 0.03Hz at 1kHz tone and 0.06Hz at 2kHz tone frequency, error > exceeding that from the receiver. > > Andy G4JNT > > > > > Assuming an overly optimistic stability of 10 ppm over the > > whole temperature excursion range > > for that crystal, this means a deviation of 0.01 Hertz for > > an audio signal of 1 kHz. > > At this frequencies, even cheap crystals can prove adequate. > > > > Thanks for your tests Alan, > > > > 73 Alberto I2PHD > > > > > > > > -- > The Information contained in this E-Mail and any subsequent correspondence > is private and is intended solely for the intended recipient(s). > For those other than the recipient any disclosure, copying, distribution, > or any action taken or omitted to be taken in reliance on such information is > prohibited and may be unlawful. From fgentges at mindspring.com Wed Jan 24 20:09:59 2001 From: fgentges at mindspring.com (Frank Gentges =?iso-8859-1?Q?K=D8BRA?=) Date: Thu Jul 3 13:43:37 2003 Subject: [Lf] News Reflector Test Message-ID: <5.0.2.1.0.20010124200809.024945a0@pop.mindspring.com> This is a test of the LF News Reflector. We seem to have a problem with one subscriber getting mail. I hope this gets through now. Sorry for the interruption, back to your spectral displays. Frank Gentges K?BRA fgentges@mindspring.com From akestelo at bellatlantic.net Thu Jan 25 08:53:31 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:37 2003 Subject: [Lf] Reality check... Message-ID: <3A702FDB.C74AE667@bellatlantic.net> Steve Olney wrote: > G'day All, > > With all the hand-wringing and lamentations about the abandonment of the > good wife CW for the QRSSS jezebel on LF, it might be useful to reflect on > the reality of the environment in which we, as Amateurs, seek to pursue our > hobby. > > I don't know about the situation elsewhere but here in VK the AVERAGE age of > an Amateur is over 60. This indicates either there are a lot of us over 60 > or there are next to no young people coming through the ranks. > > Increasing pressures on spectrum space for all sorts of wireless devices, > both long-range, satellite and short-range will see corresponding increasing > pressure on our allocations. > > The young are not motivated by traditional Amateur pursuits in sufficient > numbers to inject youth into our hobby so it is in danger of slowly becoming > an old boys' club even more than now. > > The arguments for present and new privileges (notice that the word is > privileges - not rights) have been based on experimentation, relevant > training and forming a pool of skills applicable to the current technology > environment. For example, our VK LF submission to our governing authority > makes large mention of experimentation (no mention of DXCC, QSL count, etc) > as even the old salts here realise that this is the best approach for > success in the present regulatory environment. The submission does make a > strong point for experimentation but specifically asks that operation be NOT > restricted to CW "to allow experimentation in a wider variety of > communication techniques..". > > I know in my case when applying for my Scientific Licence for operating on > LF here, I had to submit a technical reason for wanting to operate on that > band. That submission included details of narrowband experiments. If I > had just submitted it with saying I just wanted to have a CW QSO then I > would have had a snowball's hope in that hot place of succeeding. > > The world is changing and everything is increasingly being subjected to > justification. Frankly I cannot see how we have maintained our privileges > as we have in the present climate. We are up against strong commercial > pressures for spectrum space and pushing the CW, QSL card, DXCC barrow to > the detriment of more contemporary pursuits will not only not help us, it > will hinder us. > > I sympathise with those feeling the pressure of the modern age as they grow > older. This is because I too feel this pressure (although in Amateur terms > I am a spring chicken at 51), but in my case I have decided it is of no use > longing for the "good ol' days". It is a sad fact of life that CW is on > life support as it is abandoned by authorities around the world. Quoting > single instances to the contrary will not change this. > > I respectfully submit the following code of practice for us who are > interested in the Amateur hobby surviving in the new millennium. > > General: Eliminate all negative aspects of the exchanges within the > Amateur fraternity as much as possible. Encourage new ideas, embrace > technological change and generally show we are worthy of a place in the > increasingly competitive environment in which we seek to operate our hobby. > > Non-CW Types: Continue to push for new techniques, new ways, and let your > imagination and the current regulations in your location be your limit, not > some-one else's limited vision of the world. > > CW-Types: Try a new tack of keeping your particular interest alive. Try a > friendly, supportive approach instead of the Neanderthal "hit them over the > head with a club and drag them back to the cave" approach. This aggressive > approach is very effective in hiding the fun aspects of CW operation. In > fact I really believe that some of the loudest and more obnoxious CW > advocates are in reality anti-CW for the damage they do to the CW case. > > As for the Trans-Atlantic challenge. I am always for a challenge. I > guess that makes me a "young" 51-year old. My 80-year old MIL has just > started learning about computers and we have connected her to the internet. > It is a struggle for her sometimes, but she persists and is loving it. That > makes her a "young" 80-year old. Without a challenge to stimulate you, you > are just marking time. I echo a previous poster who remarked that he > would not have gone for his Amateur ticket to just engage in QSOs or to be > limited to one mode. > > There have been (and will be in the future) instances where some-one has > inadvertently transgressed into the wrong part of the "gentleman's > agreement" band space. This has been apologised for and to suggest that it > was deliberate or a sign of incompetence is, in itself, a sad sign of senile > paranoia. It is amusing that some of the least gentlemanly communicators > are demanding the strictest adherence to a "gentleman's agreement". > > Here endeth the lesson... > > 73s Steve Olney (VK2ZTO/AXSO - QF56IK : Lat -33 34 07, Long +150 44 40) > ============================================= > HomePage URLs: > http://www.qsl.net/vk2zto > http://www.zeta.org.au/~ollaneg > > Containing:- > ULF, ELF, VLF & LF Experimentation > InfraSonic Experimentation > Laser Comms DX > Amateur Radio Astronomy > ============================================= From akestelo at bellatlantic.net Thu Jan 25 14:12:02 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:37 2003 Subject: [Lf] Real radio engineering Message-ID: <3A707A81.65051803@bellatlantic.net> Subject: Diet Coke can tuner in an 80 m. xmtr [Yahoo! Clubs: The Crystal Set Radio Club] Date: Wed, 24 Jan 2001 08:15:09 PST From: rick_weber To: roneill@clark.net I was intrigued with Larry Pizzella?s (Loose-Coupler) Diet Coke Can tuner when he first posted the photo on this web site.. This past weekend, I set up my own personal challenge to build a QRP CW transmitter for 80 meters that used only ONE commercial electronic component -- a vacuum tube -- and other NON-electronic junk commonly found around the house including several Diet Coke cans. This is not a crystal radio, of course, but is in the crystal radio enthusiasts? spirit of ?minimal? design and constructtion. I started with a very old ?27 tetrode vacuum tube made in the late 1920?s. No commercial resistors, capacitors, chokes, or variable tuners were used. Capacitors were made from Diet Coke cans and clear packing tape -- two .002 mF and one 250 pF. Made the 500 pF variable condenser from one diet coke telescoping over another one with packing tape insulation. RF choke is 160 turns of wire on a ball point pen body. The 10 KOhm grid resistor was made using the old science fair trick of a soft graphite pencil rubbed on carboard. Two paper clips provided the resistor leads. Twelve turns of wire on a plastic pill bottle for the tank coil. Swing link loosely coupled to the tank coil via an LDG QRP tuner/4:1 balun to a center-fed Zepp ant. Used the rcvr part of a Sierra as my receiver. Powered the xmtr with an old 1929 ?80-based power supply. The crazy thing worked! Had a QSO Tuesday night with Bob Howard K0RDF about 350 miles away. My RST -- 239. The best I could tell, this thing was putting a little under a Watt to the antenna. Here?s a photo: http://www.vintagehamradio.com/junkbox-xmtr Here?s the total parts list for the xmtr: 1 ?27 tetrode vacuum tube 5 Diet Coke cans (capacitors) 1 Plastic pill bottle (tank coil form) 2 Ballpoint pens (one for RF choke and one for tank coil form support) 1 Roll of packing tape (insulation for caps and general) 2 paper clips (resistor leads) 1 HB pencil (resistor) Wire, epoxy, nails, cardboard, wood, solder Why use a vacuum tube instead of a transistor? I?m an OT radio nut. (The best QRP radios glow in the dark!) A lot of you rockheads out there who are also hams have a whole lot more ingenuity and skill than this old coot. Why not try your luck at a building something similar and let us know how it worked. Rick Weber W9QZ From nl9222tv at tref.nl Sat Jan 27 13:56:36 2001 From: nl9222tv at tref.nl (ko versteeg) Date: Thu Jul 3 13:43:37 2003 Subject: [Lf] Destructive Email. Message-ID: <000701c08861$21f232e0$d1da79c3@default> Hi all.. For those who suffer from Worms, Trojans, Hostile Web content, Netspionage, Data corruption, Network downtime, Productivity loss, Cyber terrorism check out http://www.finjan.com/firststrike.cfm?security=2 It does not need upgrades and is free. They have a Demo Trojan available.. (But i did not try that one) 73 de Ko, NL9222 http://leden.tref.nl/~nl9222tv/default.htm http://home.wanadoo.nl/nl9222/index.htm From akestelo at bellatlantic.net Sat Jan 27 08:30:41 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:38 2003 Subject: [Lf] Time efficient code] Message-ID: <3A72CD81.165031A8@bellatlantic.net> Rik Strobbe wrote: > If we want to develope a new 'code' for a time effecient mHz bandwidth > modulation first thing we should do is to make a list of requirements. > My list would be : > > - suitable with non-linear amplifiers : > for sake of efficiency and simplicity of the amplifier > > - be able to transmit at least 45 different 'characters' : > > - if we want to use non-linear amps we can only transmit one 'tone' at a > time, so each character needs to be transitted a a sequence of 'tones'. The > more 'tones' you use the shorter the sequence per character will be but the > larger the required bandwidth, so we will have to find a compromize between > bandwidth and speed. > eg. 47 characters can be transmitted with 7 tones and 2 sequences per > character (49 posibilities) or as 4 tones and 3 sequences per character (64 > posibilities). > > An important question is : is it worth to make things that complicated ? > Assume the transmission speed is 60 seconds dotlength. In that case the > time needed to transmit 'CQ ON7YD K' would take : > > 114 minutes in QRSS > 40 minutes in DFCW > 30 minutes in '7 tone mode' if we have a space between characters > 20 minutes in '7 tone mode' if we have no space between characters > 40 minutes in '4 tone mode' if we have a space between characters > 30 minutes in '4 tone mode' if we have no space between characters > > >From the above is clear the step from QRSS to DFCW is significant (time > reduced to 35%), but the difference between DFCW and the 'multi tone modes' > is between nil and 50%, so we should have to go to a rather complicated > system (7 tones, no spacing) to have a significant gain. > > Other opinions please ... > > 73, Rik ON7YD From akestelo at bellatlantic.net Sun Jan 28 10:19:26 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:38 2003 Subject: [Lf] Proposed new LF signal format] Message-ID: <3A74387D.5788ADB0@bellatlantic.net> Stewart Nelson wrote: > I believe that, by using a signal format designed specifically for LF > weak-signal operation, it should be possible to communicate at S/N > values at least 10 dB below what is typically needed for QRSS. Some > recent experiments by Lyle Kohler convinced me that the presently > popular modes are far from optimum, and I have written a program to > show the potential of a new mode. I call it WOLF (Weak-signal > Operation on Low Frequency). > > A while ago, Lyle comparison tested various systems commonly used for > amateur LF communication. Modes tested included conventional CW, QRSS > (decoded both visually, and aurally with CRUNCH), and several PSK > formats. Using an audio editor, Lyle mixed an attenuated copy of each > signal with a "standard" sample of noise recorded from an LF receiver. > He measured the maximum attenuation which each mode could tolerate > before copy became impossible. The results can be seen on his Web > site at http://www.computerpro.com/~lyle/weaksigs/weaksigs.htm . > > My present software is essentially an off-line demo. The transmit > mode creates a .wav file; the receive mode reads a .wav file and > attempts to decode the message. So far, it has only been tested by > mixing the Tx output with noise downloaded from Lyle's site (I am > traveling and have no LF Tx or Rx capability). But the simulated > results have been quite encouraging; there is often good copy when the > attenuation is 44 dB. This is a signal 11 dB weaker than that which > was needed by BPSK at MS1000, and 14 dB below the threshold for 0.4 > WPM QRSS. > > I would greatly appreciate any suggestions for making this system even > more robust, and encourage anyone interested to download the software > and try it. A simple test would be to mix the Tx output with your > favorite QRM or QRN and see how it fares. Much better would be trying > it on the air. If you have an SSB rig which can output LF, just play > the WOLF output file, feeding the transmitter audio from your sound > card. At the receiving end, record a .wav file from the receiver > audio, and feed it to WOLF for decoding. If you need a different > format file to key your Tx in BPSK, please let me know and I'll try > to provide it. > > Below is a brief description of the WOLF signal; you can find more > details, and the software, at http://www.scgroup.com/ham/wolf.html . > Some features of this format are: > * An explicit reference signal for robust frequency and phase lock > * Average Tx power nearly equal to PEP > * Coding to minimize number of bits for a given message > * Forward error correction with high coding gain > * Coherent detection > * Matched filter detection (bit clock derived at receiver) > * Interleaving (can tolerate gaps in reception) > > None of these ideas are new; it just seemed logical to combine > those features of modern commercial systems which offer performance > gains in our environment. > > Most amateur weak-signal work uses some form of CW or BPSK. It is > often said that, for the same PEP, BPSK has a 6 dB advantage (CW > transmits only half the average energy, and half of that is carrier > with no message content). However, CW's carrier is far from wasted. > It enables recovery of the frequency and phase of the incoming signal, > even when it is very weak. That's one reason QRSS is so popular! In > contrast, conventional BPSK relies on a non-linear process to recover > the carrier, and fails to lock when the S/N is very low. Bill > de Carle's AFRICA avoids this problem in a clever way -- by matching > the phase pattern with all possible transmitted characters. But, this > requires that any forward error correction (FEC) coding be applied > separately to each character, which limits coding gain. > > The WOLF signal is BPSK (at MS100), but after each "data" bit, a > "reference" bit is added. The reference stream is a pseudo-random > sequence which is known in advance by the receiver. The precise > frequency and phase can be measured, even when the signal is too weak > to decode the message. The reference "channel" also provides robust > bit timing and framing information, so the actual message need not > include synchronizing bits. The symbol set is limited to 40 (capital > letters, digits, space, and 3 punctuation). This permits sending > three characters using only 16 bits. A data packet is fixed at 15 > characters (80 bits), enough to send two call signs plus some report > information. A rate 1/6 convolutional code is applied to the entire > packet, resulting in a 480 bit message. Including the reference bits, > a frame has 960 bits, so it takes 96 seconds to send. > > A beacon just sends the frame repeatedly. If the signal is strong > enough for conventional CW, someone tuning it in only needs to > "listen" for a little more than 16 seconds to see the complete > message. If some error correction is required, perhaps a minute will > suffice. But if the signal is very weak, the receiving software can > integrate over as many frames as needed, until good copy is achieved. > > For two way communication, one can send a frame, and await an > acknowledgement. If not received correctly, the frame is resent, > until there is enough information for correct copy. However, I > believe that one could design a much more efficient protocol, which > should permit a QSO to be completed within one hour, even with a > signal 10 dB below the QRSS limit. See the web page for more details. > > Comments and suggestions welcome. > > 73, > > Stewart KK7KA From akestelo at bellatlantic.net Mon Jan 29 09:02:22 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:38 2003 Subject: [Lf] Earth Rods] Message-ID: <3A7577ED.16701D8E@bellatlantic.net> "Holger 'Geri', DK8KW" wrote: > Hello LF-Group, > > >I found an easy way to drive in earth rods made from copper water > >pipe is like this: I found a steel rod of a slightly bigger diameter than > >the pipe, put a point on the end, and hammered it in to the ground. < > > late Peter, DJ8WL also taught me method that is especially useful if you > have soft ground. It makes use of similar techniques as used in my business > (I am a drilling and petroleum engineer): use a garden water hose and > connect it to the upper end of the copper rod. Open the tap and simply wash > down the rod. In my relatively soft clay/shale ground it took me only a > couple of minutes to wash down a 2-meter long pipe, it depends on the water > pressure, the higher the better I (in oil-drilling business we say: the > higher the hydraulic energy at the bit is ...). > > Best 73 > > Geri, DK8KW (W1KW) From akestelo at bellatlantic.net Mon Jan 29 09:08:44 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:38 2003 Subject: [Lf] Bandwidth and receivers] Message-ID: <3A75796B.F16BB86C@bellatlantic.net> g3ldo wrote: > Bill, G0AKY said > > > All agreed in principal but there is one nail you forgot the LF band hr is > > only just over 2Khz wide > > I get the impression from Bill's comment that he, and others, think QRSS is > a wide band mode. > All other things being equal the bandwidth is inversely proportional to the > data rate, which means the bandwith for a QRSS signal is much less than a > standard CW signal. You can check this out for yourself by just looking at > these signals with QRSS SW. > When we do the transatlantic tests we often have a group of signals > transmitting a few Hz apart and each one is perfectly readable (see Ko > Versteeg's .JPG on page 98 of the LF Experimenter's book). > The main limitation of having two CW signals closer than, say, 100Hz apart > is the receiver filter. You can have very narrow filters. I have a level > meter with a 20Hz filter that certainly selects one signal from the other > and you can read CW with it provided it isn't sent too quickly. Its main > problem is that it converts every bit of noise and QRM to a tone the same as > the signal you are receiving and this is very 'wearing' after a short while. > > Most problems with receivers are due to front end non-linearity. The worst > receiver I have used that has this problem is the Daytong converter. > Nevertheless, this converter can provide excellent 'ears' (as G3XDV can > attest) provided steps are taken to reduce the input with an attenuator > and/or preselector if you are using a large antenna. > > The problem often arises when you change from a small antenna to a big > antenna. You often see it with a special event station using a big antenna > put out a huge signal but have problems hearing anyone. Seasoned LF > DXpeditioners, such as the 'Two Daves and a Graham' take with them their pet > receiver front end signal level box. > When I operate from GB2CPM the Loran comes pounding in at S9. I have to > insert some 18dB of front end attenuation plus the AIP before the weak > signals become readable. > > I live only a few miles from Laurie, G3AQC. His signal with me is S9 +35dB. > (I guess I must be as strong with him). I am able to operate on the band the > same time he is on provided I use the attenuators and provided I don't get > too close in frequency! > > Regards, > Peter, G3LDO > > From akestelo at bellatlantic.net Sun Jan 28 14:45:06 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:39 2003 Subject: [Lf] [Fwd: LF: Earthing] Message-ID: <3A7476C1.5C2F16E2@bellatlantic.net> john sexton wrote: > Hi Martin, > Glad to hear that you are getting there slowly. > You will probably get the best advice re earthing from some of the others, > but I have a couple of tips to pass on. > The antenna wire does not need to be as thick as you are proposing, 1mm > would do. Most important is height (proportional to square of). Next is > amount of top loading wire covering new ground. Laurie has some good ideas > here. I have his conclusions archived if you haven't seen them. > Earthing: Copper water pipes will bend over if you try to hammer them in. I > attached a garden hose and slowly eased them down by twisting and gently > pushing with the water flowing. If you are patient they will even go through > hard chalk as here. It doesn't matter that the ground is dry in summer, just > lay as much wire as possible and connect it to 4 or 5 earth rods. I have 10 > radials each 10 metres long. There is a lot of info about earth mats in the > LF handbook. Some lowfers attach it to the house earthing as well, but be > careful of PME mains earthing. See the RSGB handbook's advice re PME and > take it to heart. You could lose your house or worse be electrocuted. Also > probably not a good idea to extend your earth below the neighbours garden. > Hope to hear you on the band soon. Should be strong here! > 73 John, G4CNN From akestelo at bellatlantic.net Mon Jan 29 09:08:44 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:39 2003 Subject: [Lf] Bandwidth and receivers] Message-ID: <3A75796B.F16BB86C@bellatlantic.net> g3ldo wrote: > Bill, G0AKY said > > > All agreed in principal but there is one nail you forgot the LF band hr is > > only just over 2Khz wide > > I get the impression from Bill's comment that he, and others, think QRSS is > a wide band mode. > All other things being equal the bandwidth is inversely proportional to the > data rate, which means the bandwith for a QRSS signal is much less than a > standard CW signal. You can check this out for yourself by just looking at > these signals with QRSS SW. > When we do the transatlantic tests we often have a group of signals > transmitting a few Hz apart and each one is perfectly readable (see Ko > Versteeg's .JPG on page 98 of the LF Experimenter's book). > The main limitation of having two CW signals closer than, say, 100Hz apart > is the receiver filter. You can have very narrow filters. I have a level > meter with a 20Hz filter that certainly selects one signal from the other > and you can read CW with it provided it isn't sent too quickly. Its main > problem is that it converts every bit of noise and QRM to a tone the same as > the signal you are receiving and this is very 'wearing' after a short while. > > Most problems with receivers are due to front end non-linearity. The worst > receiver I have used that has this problem is the Daytong converter. > Nevertheless, this converter can provide excellent 'ears' (as G3XDV can > attest) provided steps are taken to reduce the input with an attenuator > and/or preselector if you are using a large antenna. > > The problem often arises when you change from a small antenna to a big > antenna. You often see it with a special event station using a big antenna > put out a huge signal but have problems hearing anyone. Seasoned LF > DXpeditioners, such as the 'Two Daves and a Graham' take with them their pet > receiver front end signal level box. > When I operate from GB2CPM the Loran comes pounding in at S9. I have to > insert some 18dB of front end attenuation plus the AIP before the weak > signals become readable. > > I live only a few miles from Laurie, G3AQC. His signal with me is S9 +35dB. > (I guess I must be as strong with him). I am able to operate on the band the > same time he is on provided I use the attenuators and provided I don't get > too close in frequency! > > Regards, > Peter, G3LDO > > From akestelo at bellatlantic.net Sun Jan 28 10:19:26 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:39 2003 Subject: [Lf] Proposed new LF signal format] Message-ID: <3A74387D.5788ADB0@bellatlantic.net> Stewart Nelson wrote: > I believe that, by using a signal format designed specifically for LF > weak-signal operation, it should be possible to communicate at S/N > values at least 10 dB below what is typically needed for QRSS. Some > recent experiments by Lyle Kohler convinced me that the presently > popular modes are far from optimum, and I have written a program to > show the potential of a new mode. I call it WOLF (Weak-signal > Operation on Low Frequency). > > A while ago, Lyle comparison tested various systems commonly used for > amateur LF communication. Modes tested included conventional CW, QRSS > (decoded both visually, and aurally with CRUNCH), and several PSK > formats. Using an audio editor, Lyle mixed an attenuated copy of each > signal with a "standard" sample of noise recorded from an LF receiver. > He measured the maximum attenuation which each mode could tolerate > before copy became impossible. The results can be seen on his Web > site at http://www.computerpro.com/~lyle/weaksigs/weaksigs.htm . > > My present software is essentially an off-line demo. The transmit > mode creates a .wav file; the receive mode reads a .wav file and > attempts to decode the message. So far, it has only been tested by > mixing the Tx output with noise downloaded from Lyle's site (I am > traveling and have no LF Tx or Rx capability). But the simulated > results have been quite encouraging; there is often good copy when the > attenuation is 44 dB. This is a signal 11 dB weaker than that which > was needed by BPSK at MS1000, and 14 dB below the threshold for 0.4 > WPM QRSS. > > I would greatly appreciate any suggestions for making this system even > more robust, and encourage anyone interested to download the software > and try it. A simple test would be to mix the Tx output with your > favorite QRM or QRN and see how it fares. Much better would be trying > it on the air. If you have an SSB rig which can output LF, just play > the WOLF output file, feeding the transmitter audio from your sound > card. At the receiving end, record a .wav file from the receiver > audio, and feed it to WOLF for decoding. If you need a different > format file to key your Tx in BPSK, please let me know and I'll try > to provide it. > > Below is a brief description of the WOLF signal; you can find more > details, and the software, at http://www.scgroup.com/ham/wolf.html . > Some features of this format are: > * An explicit reference signal for robust frequency and phase lock > * Average Tx power nearly equal to PEP > * Coding to minimize number of bits for a given message > * Forward error correction with high coding gain > * Coherent detection > * Matched filter detection (bit clock derived at receiver) > * Interleaving (can tolerate gaps in reception) > > None of these ideas are new; it just seemed logical to combine > those features of modern commercial systems which offer performance > gains in our environment. > > Most amateur weak-signal work uses some form of CW or BPSK. It is > often said that, for the same PEP, BPSK has a 6 dB advantage (CW > transmits only half the average energy, and half of that is carrier > with no message content). However, CW's carrier is far from wasted. > It enables recovery of the frequency and phase of the incoming signal, > even when it is very weak. That's one reason QRSS is so popular! In > contrast, conventional BPSK relies on a non-linear process to recover > the carrier, and fails to lock when the S/N is very low. Bill > de Carle's AFRICA avoids this problem in a clever way -- by matching > the phase pattern with all possible transmitted characters. But, this > requires that any forward error correction (FEC) coding be applied > separately to each character, which limits coding gain. > > The WOLF signal is BPSK (at MS100), but after each "data" bit, a > "reference" bit is added. The reference stream is a pseudo-random > sequence which is known in advance by the receiver. The precise > frequency and phase can be measured, even when the signal is too weak > to decode the message. The reference "channel" also provides robust > bit timing and framing information, so the actual message need not > include synchronizing bits. The symbol set is limited to 40 (capital > letters, digits, space, and 3 punctuation). This permits sending > three characters using only 16 bits. A data packet is fixed at 15 > characters (80 bits), enough to send two call signs plus some report > information. A rate 1/6 convolutional code is applied to the entire > packet, resulting in a 480 bit message. Including the reference bits, > a frame has 960 bits, so it takes 96 seconds to send. > > A beacon just sends the frame repeatedly. If the signal is strong > enough for conventional CW, someone tuning it in only needs to > "listen" for a little more than 16 seconds to see the complete > message. If some error correction is required, perhaps a minute will > suffice. But if the signal is very weak, the receiving software can > integrate over as many frames as needed, until good copy is achieved. > > For two way communication, one can send a frame, and await an > acknowledgement. If not received correctly, the frame is resent, > until there is enough information for correct copy. However, I > believe that one could design a much more efficient protocol, which > should permit a QSO to be completed within one hour, even with a > signal 10 dB below the QRSS limit. See the web page for more details. > > Comments and suggestions welcome. > > 73, > > Stewart KK7KA From akestelo at bellatlantic.net Mon Jan 29 09:02:22 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:39 2003 Subject: [Lf] Earth Rods] Message-ID: <3A7577ED.16701D8E@bellatlantic.net> "Holger 'Geri', DK8KW" wrote: > Hello LF-Group, > > >I found an easy way to drive in earth rods made from copper water > >pipe is like this: I found a steel rod of a slightly bigger diameter than > >the pipe, put a point on the end, and hammered it in to the ground. < > > late Peter, DJ8WL also taught me method that is especially useful if you > have soft ground. It makes use of similar techniques as used in my business > (I am a drilling and petroleum engineer): use a garden water hose and > connect it to the upper end of the copper rod. Open the tap and simply wash > down the rod. In my relatively soft clay/shale ground it took me only a > couple of minutes to wash down a 2-meter long pipe, it depends on the water > pressure, the higher the better I (in oil-drilling business we say: the > higher the hydraulic energy at the bit is ...). > > Best 73 > > Geri, DK8KW (W1KW) From akestelo at bellatlantic.net Sun Jan 28 11:24:38 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:39 2003 Subject: [Lf] Re: LF: Proposed new LF signal format References: <23564246.980604804777.JavaMail.imail@chilly.excite.com> <001b01c08870$f6b97d80$d400a8c0@scgroup.com> Message-ID: <3A7447C6.B890F46B@bellatlantic.net> Stewart Nelson wrote: > [...] The WOLF signal is BPSK (at MS100), > [...] > Comments and suggestions welcome. > 73, > Stewart KK7KA Stewart is to be commended for developing the very interesting WOLF concept. One of the challenges we all face in LF work is the _reliable_ operation of high-power CW transmitters (I have a bunch of fried Power MosFets here in the shack that demonstrate that problem). Generating large amounts of RF power with a _linear_ amplifier is even more difficult, because of the problem one faces when one tries to bias several power MosFets in parallel. (I am assuming here that most radioamateurs will try to use cheap Mosfets, not expensive RF types). Ideally, for such applications as WOLF, one would need a linear amplifier, yet what cheap power MosFets seem to like best is on/off operation :-) One approach to that problem was offered by Timothy Hulick Ph.D. W9QQ, in two papers he presented at the AMRAD Technical Symposium that was held here in Virginia on 17 June 2000. These papers: "The Digital Amplitude Modulator" and "The Digital Linear Amplifier" were reprinted in the Symposium's proceedings. 73 Andre' N4ICK From fgentges at mindspring.com Mon Jan 29 15:49:37 2001 From: fgentges at mindspring.com (Frank Gentges =?iso-8859-1?Q?K=D8BRA?=) Date: Thu Jul 3 13:43:40 2003 Subject: [Lf] Peter Dodd's LF Handbook Message-ID: <5.0.2.1.0.20010129154037.00a97710@pop.mindspring.com> LFers, I just got a copy delivered from ARRL of Peter Dodd's (G3LDO) "LF Experimenter's Handbook" from the ARRL On Line Store. Several of you wanted it and I was trying to get it from Britain but it was getting too hard. In the end, I did not order any for anyone. I saw it on the ARRL web site and I wanted to see if it actually works. It does. This is the book that Andre' brought back with him on his trip to Europe in October. Check out . It is about 1/3 the way down the page. Frank Frank Gentges K?BRA fgentges@mindspring.com From akestelo at bellatlantic.net Wed Jan 31 10:14:56 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:40 2003 Subject: [Lf] Efficiency at LF Message-ID: <3A782BEF.15D590CE@bellatlantic.net> Mike Dennison wrote: > I run 700W RF to make less than 200mW ERP. Is that QRO or QRP? > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From akestelo at bellatlantic.net Wed Jan 31 10:27:14 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:40 2003 Subject: [Lf] UK HAm received in the US ! Message-ID: <3A782ED2.53D7DA2A@bellatlantic.net> Les Rayburn wrote: > [...] > Are you able to receive the European LF hams very well at your location? > Dexter in > North Carolina logged his second European ham last night on QRSS...but he > is right by the coast in a good low noise location. > > So far, I have only been able to receive your beacon and the AMRAD > beacon...nothing > yet from across the pond. > > Les Rayburn, N1LF > 4919 Cox Cove > Helena, AL 35080 > XMGR 184.900khz > 1LF 187.300khz From akestelo at bellatlantic.net Wed Jan 31 10:29:44 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:40 2003 Subject: [Lf] Re. 135 Last night] Message-ID: <3A782F67.5C5B58CC@bellatlantic.net> Kudos to Dexter :-) Andre' N4ICK Dexter McIntyre w4dex wrote: > Laurie, > > I would not have seen your signal if you were on or below 135.921. I > was running Argo in 60 second dot mode and was only viewing from .921 to > .924. I had selected this so I could see both your and Jim's > frequency. On the Argo scale 1851 hz is 135.92105 and the 1854 hz mark > is 135.92405. The 2 + minuet mark near center at the 1854 line is my > reference marker on 135.924. It is about .5 hz low of the Argo line and > is the reason for the .5 hz offset. > > http://dmcintyre.home.att.net/135923on30Jan01.jpg > > After reviewing all captured shots for the night I suspect your signal > may be just below the frequency line at 1851 hz on Argo. This frequency > line and the one at approximately 1853.6 are always present at night > here so please try to avoid this frequency. Looking right at the bottom > edge of the shot and on many other shots I can see what may be your > signal. I'm sure sorry I missed it if that is so. > > Jim, M0BMU, has verified his signal at 135.924 KHz. His fast CW id can > even be seen as a blur just before the first 110 second dash. I lost > his signal shortly after this shot. Jim reported his insulators melted > at 0130 UT. This shot was made at 0114 UT. > > I will be listening anytime your advise of your transmitting but looks > like QRN is on the menu for tonight. > > 73, > Dexter > > LAWRENCE MAYHEAD wrote: > > > > Hi Dexter and Larry, > > Looks like Jim made it across last night,congratulations Dex and Jim. > > I was on 135,919.9-,922 near as I can get but the 135,923 signal definately > > Jims. With my low power I need better condx..We may have a CME tonight, > > but I will be on again from 19:30. 73s Laurie. From akestelo at bellatlantic.net Wed Jan 31 10:03:15 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:40 2003 Subject: [Lf] Propagation] Message-ID: <3A782933.1FFE72ED@bellatlantic.net> Johan Bodin wrote: > Hi All, > > At my QTH, the Icelandic BC stations on 189 and 207 kHz have been > much stronger than usual during the recent nights. I am using a K9AY > antenna for receiving (cardioid pattern) and when I point the "null" > toward the QRM from the south, the signals from Iceland pops up with > "local quality"! > > Last winter I tried hard to hear Iceland on LF but most of the time I was > only able to detect the presence of the carrier. Now, the signal is strong > enough to enjoy the program with a simple AM receiver. > > At the time of this writing, Iceland is booming in on 189 kHz but the "Loran > rattle" on 136 kHz, which is usually clearly audible, is not there... CME? > > Also, I have noticed a *very* pronounced "Luxembourg effect" on the Donebach > signal on 153 kHz during the recent nights. A lot of programmes were heard > simultaneously. Sometimes Radio Norway (1314? 630?) sounded almost > as strong as the original modulation! I find this hard to understand since the > "ionospheric modulator" (Norway) is *NOT* between me and the LF TX! > > Has anyone else noticed this? > > 73 > > Johan Bodin, SM6LKM From ollaneg at zeta.org.au Wed Jan 31 07:37:01 2001 From: ollaneg at zeta.org.au (Steve Olney) Date: Thu Jul 3 13:43:40 2003 Subject: [Lf] FDK Beacon Project... Message-ID: <000f01c08afd$ba093b20$0301a8c0@steve> G'day All, I have just put up preliminary specifications and descriptions about an FDK beacon project I am working on. I would appreciate any comments and suggestions. Please go to:- http://www.qsl.net/vk2zto and scroll down to the Experimental Modes section. Click on FDK Beacon Project. 73s Steve Olney (VK2ZTO/AXSO - QF56IK : Lat -33 34 07, Long +150 44 40) ============================================= HomePage URLs: http://www.qsl.net/vk2zto http://www.zeta.org.au/~ollaneg Containing:- ULF, ELF, VLF & LF Experimentation InfraSonic Experimentation Laser Comms DX Amateur Radio Astronomy ============================================= From akestelo at bellatlantic.net Tue Jan 30 10:02:08 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:41 2003 Subject: [Lf] Ground rods Message-ID: <3A76D76F.BE9AA20D@bellatlantic.net> An alternative to 'brute force' to get a pipe in the ground is to use water : connect one end to a garden hose, put the pipe vertical (with the garden hose end up) and let the water flow. The pipe will gently slide into the ground, unles you have a very 'rocky' ground. Reduce the water flow for when you get the last meter in the ground and secure the pipe for some days (weeks) to avoid a 'China syndrome'. For a picture of this procedure have a look at : http://www.qsl.net/on7yd/136ant.htm#Radials BTW : if prefer galvanized iron pipes, if you have 'acid soil' it will 'eat' your copper pipe. 73, Rik ON7YD From akestelo at bellatlantic.net Sat Feb 3 10:01:00 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:41 2003 Subject: [Lf] G3AQC complete call Q5 in USA] Message-ID: <3A7C1D2B.E04C9BF2@bellatlantic.net> G0MRF@aol.com wrote: > I e-mailed Dexter and told him that a complete callsign was probably needed. > The very next day he found one! > > I think to that point he had just identified signals by seeing odd characters > or by identifying dashes with the correct on/off sequence on the correct > frequency. > > So to the best of my knowledge Laurie's was the first full callsign received, > whereas Jim's signal was positively identified by other means. > > That's the same situation that occured between Canada and the UK. Where Jack, > VE1ZZ, was positively identified on 10/sept by a prearranged series of dashes > (Marconi style). At that time Jack could not transmit his call in QRSS so the > 'formal' reception had to wait until a beacon keyer was sent over from the UK > and Jack's callsign was received by Peter G3LDO several weeks later. > > Look's like the various sections of the AMRAD / RSGB / DARC challenge are > slowly being achieved. I wonder if this will spur us onto monitoring the > AMRAD beacons. > Be prepared for requests to slow down the keying Andre' (Hi) > > Thanks to all three organisations for the inspiration to do all this. > > 73 > > David G0MRF From akestelo at bellatlantic.net Sat Feb 3 10:13:13 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:41 2003 Subject: [Lf] Re: LF: G3AQC complete call Q5 in USA References: <3.0.1.16.20010203164017.3fd7a4a4@mail.cc.kuleuven.ac.be> Message-ID: <3A7C2009.28DC7209@bellatlantic.net> Rik Strobbe wrote: > Congrats to Laurie & Dexter. > It seems that 60 sec./dot opens a complete new world of posibilities. > Two things to do now : > - try to get some (more) transmitting activity at the western side of the > pond ('wake' the AMRAD licences ?) [...] > 73, Rik ON7YD The problem is not with the AMRAD licenses, unfortunately. The FCC issued us (AMRAD) a "Part 5 license", i.e., an experimental license that only allows us to talk to one another, not as amateur operators, but as experimenters. (We all have the same call-sign WA2XTF). Hence we cannot communicate with other hams. Meanwhile, we have also petitioned the FCC for an allocation similar to the CEPT one which you enjoy in Europe (135-137 kHz). This has been languishing somewhere, but we are having regular contacts with the FCC and are hopeful that we will, one day, obtain that sliver. One of the problems we have encountered is that the FCC was also petitioned to allocate the whole 160-190 kHz band to the amateurs, something that is being opposed by some electric power companies,as those use that band to transmit signals over their own lines, for control and monitoring purposes. 73 Andre' N4ICK From dmcintyre at att.net Sat Feb 3 18:29:44 2001 From: dmcintyre at att.net (Dexter McIntyre w4dex) Date: Thu Jul 3 13:43:41 2003 Subject: [Lf] Re: LF: G3AQC copied in Virginia References: <01C08DFD.3A87E240.esanders@erols.com> Message-ID: <3A7C9468.37970A3@att.net> Sandy, That's great! I was beginning to feel like there was some question about the authenticity of my reports. Your report should remove any doubts. To do this with a 50 cm E field probe should encourage many others to listen. I was also surprised to find what I thought would be my noisiest antenna to work the best. I tried large multiturn tuned balanced loops, a large shielded unbalanced loop, a tuned 200 foot per side square horizontal loop and a beverage. Then I find my 160 meter dipole fed as a T, right above the house, close to many noise sources, receives 136 KHz the best! The only noise source I have noticed is from a light dimmer. Now that's noise! 73, Dexter Nan and Sandy Sanders wrote: > > From about 0030 GMT to about 0230 GMT and again from about 0330 GMT to > about 0600 GMT I was able to copy G3AQC . I also copied dashes from M0BMU ( > who was a bit stronger in the first time period but only lasted about half > the second period ). There was also a very faint broken line that could > have been G3XTZ but was never strong enough to copy any letters. I used > ARGO build 113 in 30s dot mode agc on. > I plan to download build 117 and give it a try tonight. > The most interesting thing I find about this reception is the receive > antenna is a 50 cm long E field probe mounted 50 cm above the flat metal > roof of a three story office building full of computers. It is able to hear > much better than all but 1 or 2 of the home stations in this area. > Sandy > WB5MMB From akestelo at bellatlantic.net Mon Feb 5 09:13:56 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:41 2003 Subject: [Lf] Earthing the mast] Message-ID: <3A7EB524.F6E2D039@bellatlantic.net> Mike Dennison wrote: > A few weeks ago there was a discussion about whether to earth > masts, or leave them 'floating'. > > In the continuous search for more dBs I tried earthing my mast on > Saturday. > > I have a 14m (45ft) mast attached to the brick wall of the house by > 'T' and 'K' brackets, standing off about 300mm (1ft). Its base is > 600mm (2ft) above ground level. The vertical part of the antenna is > about 1m (3ft) away from the mast. > > I connected the mast to the wire which runs from the Tx to the earth > stakes. I expected the capacitance between the mast and the > vertical to change the tuning. The change was in fact very small, but > the first thing I noticed was the variometer tuning became much > more critical. The second thing was a 10 per cent increase in > antenna current. Conclusion: the Q of the antenna had increased. > > I was still prepared to believe that I had simply added a capacitor > from the antenna to earth, but when I checked the receive > performance the signals improved by 1-2dB (tested by monitoring > DCF and detuning until one of the 'S-meter' LCD blobs flickered, > then noting that the blob stayed on with the earth connected), and > the local noise level reduced at the same time. > > Another effect, in the short time since I made this change, has been > the antenna current has been stable. Before, it would vary by > between 10 and 20 percent from one day to the next, depending on > the weather, and I assumed this was absorption by trees. > > It seems that the mast/wall was acting as a resistor to earth, > absorbing a different amount of RF from day to day. > > I also earthed the mast at the far end of my inverted-L and > connected the two with a wire, but this had much less effect. This > mast is already stuck in the mud at its base so was probably already > earthy. > > What to do next? > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From dmcintyre at att.net Sat Feb 3 18:29:44 2001 From: dmcintyre at att.net (Dexter McIntyre w4dex) Date: Thu Jul 3 13:43:42 2003 Subject: [Lf] Re: LF: G3AQC copied in Virginia References: <01C08DFD.3A87E240.esanders@erols.com> Message-ID: <3A7C9468.37970A3@att.net> Sandy, That's great! I was beginning to feel like there was some question about the authenticity of my reports. Your report should remove any doubts. To do this with a 50 cm E field probe should encourage many others to listen. I was also surprised to find what I thought would be my noisiest antenna to work the best. I tried large multiturn tuned balanced loops, a large shielded unbalanced loop, a tuned 200 foot per side square horizontal loop and a beverage. Then I find my 160 meter dipole fed as a T, right above the house, close to many noise sources, receives 136 KHz the best! The only noise source I have noticed is from a light dimmer. Now that's noise! 73, Dexter Nan and Sandy Sanders wrote: > > From about 0030 GMT to about 0230 GMT and again from about 0330 GMT to > about 0600 GMT I was able to copy G3AQC . I also copied dashes from M0BMU ( > who was a bit stronger in the first time period but only lasted about half > the second period ). There was also a very faint broken line that could > have been G3XTZ but was never strong enough to copy any letters. I used > ARGO build 113 in 30s dot mode agc on. > I plan to download build 117 and give it a try tonight. > The most interesting thing I find about this reception is the receive > antenna is a 50 cm long E field probe mounted 50 cm above the flat metal > roof of a three story office building full of computers. It is able to hear > much better than all but 1 or 2 of the home stations in this area. > Sandy > WB5MMB From akestelo at bellatlantic.net Mon Feb 5 09:32:17 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:42 2003 Subject: [Lf] Re: LF: G3AQC complete call Q5 in USA References: <3.0.1.16.20010203164017.3fd7a4a4@mail.cc.kuleuven.ac.be> <3.0.1.16.20010205150224.2dbfd5ba@mail.cc.kuleuven.ac.be> Message-ID: <3A7EB971.E29A9C0E@bellatlantic.net> Rik Strobbe wrote: > Hi Andr?, > > >The problem is not with the AMRAD licenses, unfortunately. The FCC issued us > >(AMRAD) a "Part 5 license", i.e., an experimental license that only allows us > >to talk to one another, not as amateur operators, but as experimenters. (We > >all have the same call-sign WA2XTF). Hence we cannot communicate with other > >hams. > > I wasn't aware of that. But since Dexter could copy UK stations running > abt. 350mW ERP it might be worth putting up a 24h beacon arround 137790, > would allow the Eu's to monitor beacons in the US and Canada at same time > (just stay a few Hz away from Larry). For more than one year now, we have had a QRS beacon on the air 24/7 (at least, weather permitting) but our presnt "Part 5" license only allows us to transmit on 136.750 +/- 5 Hz. Our beacon is being heard, and seen, regularly in London (but that is London, Ontario, not London UK) 73 Andre' From esanders at erols.com Sat Feb 3 16:19:34 2001 From: esanders at erols.com (Nan and Sandy Sanders) Date: Thu Jul 3 13:43:42 2003 Subject: [Lf] G3AQC copied in Virginia Message-ID: <01C08DFD.3A87E240.esanders@erols.com> From about 0030 GMT to about 0230 GMT and again from about 0330 GMT to about 0600 GMT I was able to copy G3AQC . I also copied dashes from M0BMU ( who was a bit stronger in the first time period but only lasted about half the second period ). There was also a very faint broken line that could have been G3XTZ but was never strong enough to copy any letters. I used ARGO build 113 in 30s dot mode agc on. I plan to download build 117 and give it a try tonight. The most interesting thing I find about this reception is the receive antenna is a 50 cm long E field probe mounted 50 cm above the flat metal roof of a three story office building full of computers. It is able to hear much better than all but 1 or 2 of the home stations in this area. Sandy WB5MMB From esanders at erols.com Sun Feb 4 12:18:41 2001 From: esanders at erols.com (Nan and Sandy Sanders) Date: Thu Jul 3 13:43:42 2003 Subject: [Lf] 04Feb reception Message-ID: <01C08EA4.A1F14BE0.esanders@erols.com> If the imagination filter was not turned up too high (first try at DFCW hi hi). 04:17 GMT to 04:40 GMT copied "QC G3". Between 07:50 and 08:40 copied "G A QC" with QC being about the strongest of the night. Signals were a lot better last night. When I get more time I will see if I can pull any more out. Sandy WB5MMB From akestelo at bellatlantic.net Sun Feb 4 14:10:48 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:42 2003 Subject: [Lf] Re: LF: PLL inaccuracy References: <2f.fe468b0.279be61d@aol.com> Message-ID: <3A7DA938.41FC437F@bellatlantic.net> WarmSpgs@aol.com wrote: > There does not have to be a frequency error at all for a phase comparator to > output a correction voltage...only for the oscillator being stabilized to > have a _tendency_ to drift away from the desired frequency, which is > inevitable. Hence, once lock has been achieved, a more-or-less constant > phase difference is maintained by the loop. This is not frequency error. I am not quite convinced yet... :-) > Time is the difference between frequency and phase, as in Alan's analysis. A > _frequency_ difference between two signals means the _phase_ relationship is > changing continuously in the same direction over the course of time. If f1 > > f2, the phase of f1 is constantly advancing relative relative to that of f2, > for just as long as the frequency difference is allowed to exist. This is > the condition when lock has not been achieved. Allow me to quote from the book "Phase Locked Loops, Principle and Practice", McGraw Hill 1996, by P.V. Brennan University College, London. Page 22: "...As far as the control loop is concerned, it should be noted that frequency dividers act equally as phase dividers, so that a factor of 1/N must be allowed for in the loop equations". > When a PLL achieves lock, phase of the controlled oscillator is NOT allowed to > move continuously in either direction. There may be short-term variations > around the center, but no continuing trend (thus, phase lock). Without > continuous phase change in a given direction, there is no frequency error > relative to the reference. The remaining short term variations around the > desired phase relationship are simply that: phase noise, or jitter. Now from the same book, page 128, where the author describes a PLL that includes a divider-by-1000 between the VCO and the phase comparator: "...the implementation of figure 8.6 has a resolution of 0.35 degrees. Although this may sound impressive, it should be realized that the resolution referred to the VCO is worsened by a factor of N, to 350 degrees for example, with a divider ratio of 1000." 73 Andre' N4ICK From esanders at erols.com Sun Feb 4 12:18:41 2001 From: esanders at erols.com (Nan and Sandy Sanders) Date: Thu Jul 3 13:43:42 2003 Subject: [Lf] 04Feb reception Message-ID: <01C08EA4.A1F14BE0.esanders@erols.com> If the imagination filter was not turned up too high (first try at DFCW hi hi). 04:17 GMT to 04:40 GMT copied "QC G3". Between 07:50 and 08:40 copied "G A QC" with QC being about the strongest of the night. Signals were a lot better last night. When I get more time I will see if I can pull any more out. Sandy WB5MMB From akestelo at bellatlantic.net Sun Feb 4 14:10:48 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:43 2003 Subject: [Lf] Re: LF: PLL inaccuracy References: <2f.fe468b0.279be61d@aol.com> Message-ID: <3A7DA938.41FC437F@bellatlantic.net> WarmSpgs@aol.com wrote: > There does not have to be a frequency error at all for a phase comparator to > output a correction voltage...only for the oscillator being stabilized to > have a _tendency_ to drift away from the desired frequency, which is > inevitable. Hence, once lock has been achieved, a more-or-less constant > phase difference is maintained by the loop. This is not frequency error. I am not quite convinced yet... :-) > Time is the difference between frequency and phase, as in Alan's analysis. A > _frequency_ difference between two signals means the _phase_ relationship is > changing continuously in the same direction over the course of time. If f1 > > f2, the phase of f1 is constantly advancing relative relative to that of f2, > for just as long as the frequency difference is allowed to exist. This is > the condition when lock has not been achieved. Allow me to quote from the book "Phase Locked Loops, Principle and Practice", McGraw Hill 1996, by P.V. Brennan University College, London. Page 22: "...As far as the control loop is concerned, it should be noted that frequency dividers act equally as phase dividers, so that a factor of 1/N must be allowed for in the loop equations". > When a PLL achieves lock, phase of the controlled oscillator is NOT allowed to > move continuously in either direction. There may be short-term variations > around the center, but no continuing trend (thus, phase lock). Without > continuous phase change in a given direction, there is no frequency error > relative to the reference. The remaining short term variations around the > desired phase relationship are simply that: phase noise, or jitter. Now from the same book, page 128, where the author describes a PLL that includes a divider-by-1000 between the VCO and the phase comparator: "...the implementation of figure 8.6 has a resolution of 0.35 degrees. Although this may sound impressive, it should be realized that the resolution referred to the VCO is worsened by a factor of N, to 350 degrees for example, with a divider ratio of 1000." 73 Andre' N4ICK From akestelo at bellatlantic.net Mon Feb 5 12:04:52 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:43 2003 Subject: [Lf] WA2XTF beacon References: <3A7EC25C.23669.13BB591@localhost> Message-ID: <3A7EDD33.5AECC6BB@bellatlantic.net> Hello Mike, Absolutely, we can transmit at any speed we want The only limitation would be the ON7YD QRS program: does it allow us to go slower? (I cannot remember its parameters, and the actual software is at the transmitter site, of course, not here in my shack, so I cannot check now how slow it will go). What do you have in mind? 73 Andr? N4ICK ********************************** Mike Dennison wrote: > > For more than one year now, we have had a QRS beacon on the air 24/7 > > (at least, weather permitting) but our presnt "Part 5" license only > > allows us to transmit on 136.750 +/- 5 Hz. Our beacon is being heard, > > and seen, regularly in London (but that is London, Ontario, not London > > UK) 73 Andre' > > Andre, > > Presumably this is 3s dot QRS. Are you permitted to go to much > longer dots? > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From akestelo at bellatlantic.net Mon Feb 5 12:10:05 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:43 2003 Subject: [Lf] Re: LF: PLL / Loop antennas References: <5501.200102051521@gemini> Message-ID: <3A7EDE6C.D537F511@bellatlantic.net> James Moritz wrote: > Re: Phase locked loops; Andre wrote- > > >"...the implementation of figure 8.6 has a resolution of 0.35 > > degrees. > > A fixed error in frequency means a constantly increasing error in phase. Suppose a phase locked loop has a reference frequency of 1MHz exactly, and is trying to lock a VCO which is running at 1.000001MHz. If both reference and VCO have the same phase at one particular moment, one cycle later the VCO will be leading in phase by 1e-6 cycles, or 0.00036 degrees, which may well be lost in the noise and other errors at the phase detector output. But after 2 cycles it will be 0.00072 degrees, after about 972 cycles, the accumulated phase error will be 0.35 degrees, and after 1000000 cycles it will be 360 degrees. However small the frequency error, over a long enough time the phase error will increase to the point where it becomes the dominant signal in the feedback loop - probably a rather small fraction of a second in the above example. Yes Jim, I agree entirely. That is why my original posting mentioned that whenever we insert a divider-by-N between VCO and phase detector, we must keep in mind that the VCO can drift N times more than the phase angle at the phase detector/comparator. That error may, or may not be significant. 73 Andre' From akestelo at bellatlantic.net Mon Feb 5 17:28:21 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:43 2003 Subject: [Lf] Loop antennas Message-ID: <3A7F2904.183EB6C9@bellatlantic.net> Re - loop antennas - Marcus wrote: >I'll repeat those readings on a 4m diameter aluminum loop, 17mm >tube, assoon as I finish my remotely controlled capacitor decade >circuit (1nf steps from 0 to 350nf). Seems that the 1 turn solution >will perform well -and the best part - no pre-amp, but the decade C >:o( In theory and to a reasonable approximation, the SNR of a loop depends only upon it's effective area and Q, and not on the number of turns. This assumes a preamp or receiver input which does not add significantly to the noise generated by the loop itself, which is usually possible. So a 1 turn loop is quite reasonable, with obvious mechanical advantages. But there are also difficulties. Tuning capacitance has to be very large at LF. Impedances are very low, so resistances must also be kept very low in order to avoid severely reducing Q. At U of H, we found wide range, switched tuning capacitors difficult to implement with a single turn loop, mostly due to trouble finding low-resistance switches. In the LF range, and loop inductances of the order of 10s of uH, 0.1 ohm will be significant. Bearing in mind multiple switches will probably be needed, this can be a real problem. We found relays were really the only option for remote switching, and even then you have to be careful - reed relays had losses around 0.1 - 0.5 ohms, much higher than their DC resistance. The best bet are relays intended for UHF antenna changeover duty. However, problems can be greatly eased by going to larger loop sizes - with the increased signal level, and the high noise levels on LF, optimum Q is not then required, and tuning arrangements are less critical. I am currently using 2 square, single turn loops with 3m sides, made from 1.5mm^2 wire, mounted on the same pole, roughly at right angles. One of the two loops is selected by a relay, giving 360 degree coverage. This is connected to a tuner in the shack by about 25m of RG58 coax. the tuner has (for 136kHz), a 700uH inductor in series with the loop, tuned by about 2nF to ground. A high impedance preamp input is connected to the hot end of the tuning C. Although this is far from optimum from the noise viewpoint, external noise appears to be the limit on sensitivity. This antenna has worked well for receiving the various transatlantic signals. It can be tuned over a wide range by switching in different tuning capacitors and inductors, and has also worked well for 73kHz. Cheers, Jim Moritz 73 de M0BMU From akestelo at bellatlantic.net Tue Feb 6 10:11:30 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:43 2003 Subject: [Lf] Is this the Amrad Beacon? Message-ID: <3A801421.5B8854ED@bellatlantic.net> john sexton wrote: > Hi All, > I used Argo last night to monitor the Amrad Beacon frequency at 136.750 kHz > and found a signal precisely on frequency to within 0.01 Hz. I used the > highest resolution of 120 sec dots, which means that one cannot see the QRSS > coding, which is probably 3 sec dots, but the signal could probably not be > seen at all if I had set Argo to that dot length. I used the Loran lines to > calibrate Argo. > > To see the best image click on www.g4cnn.f2s.com/amradbeacon.jpg. The signal > is about 0.01 Hz low in this picture, but when I recalibrated Argo this > morning, I found the nearest Loran line at 136751.5669 also appeared 0.01 Hz > low, so this is just a calibration error (still learning). > > The signal was visible from about 22.00 last night (010205) until 06.00 this > morning when it died out. > I saw no clear "Dawn effect" on the QRN in these images, but the QRN is low > throughout, which might be a result of using this resolution, or perhaps the > different frequency. > > In order to measure to 0.01 Hz accurately, I had to import the images into > Paint Shop Pro and use the vernier to measure the difference in position of > two consecutive 1 Hz marks and the line. The lack of finer vertical scaling > in Argo is the one minor deficiency in this otherwise excellent package. > Thanks Alberto. > > 73, John, G4CNN > > _______________________________________________________ > Send a cool gift with your E-Card > http://www.bluemountain.com/giftcenter/ From akestelo at bellatlantic.net Tue Feb 6 10:08:24 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:43 2003 Subject: [Lf] Luxembourg effect at 137.7] Message-ID: <3A801368.DFE64031@bellatlantic.net> john sexton wrote: > Hi Mike, > Yes, I think you are right about the "Luxemburg effect" at the top of our > band, being the main source of the noise that disappears at dawn. I have > always assumed that it is modulation of DBF39 by broadcast stations. It is > not really intelligible, so I was going to use a second receiver to see if I > could match it with BBC 4 or other strong European stations, but haven't got > round to it yet. > > When I monitored Jack's signal overnight on the 1st of Feb, I did see a > reduction of noise at 06.20, but it was much less marked than when > monitoring 137.790. > > 73, John, G4CNN > > _______________________________________________________ > Send a cool gift with your E-Card > http://www.bluemountain.com/giftcenter/ From akestelo at bellatlantic.net Tue Feb 6 10:13:15 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:44 2003 Subject: [Lf] [Fwd: LF: WA2XTF beacon] Message-ID: <3A80148B.EF54F6BD@bellatlantic.net> Mike Dennison wrote: > > Absolutely, we can transmit at any speed we want > > The only limitation would be the ON7YD QRS program: does it allow us > > to go slower? (I cannot remember its parameters, and the actual > > software is at the transmitter site, of course, not here in my shack, > > so I cannot check now how slow it will go). What do you have in mind? > > 73 Andr? N4ICK > > Well, there has been considerable success with Gs being received > in Canada and the US using 30 - 60 second dot speeds when faster > rates failed. Assuming you have some reasonable data on reception > with 3s dots, how about reducing the speed to see how your range > improves? Argo will cope with 90s dot lengths, so anything up to that > would do. > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From esanders at erols.com Wed Feb 7 21:54:50 2001 From: esanders at erols.com (Nan and Sandy Sanders) Date: Thu Jul 3 13:43:44 2003 Subject: [Lf] AMRAD Beacon Message-ID: <01C09150.9C612FC0.esanders@erols.com> Here is what the amrad beacon looks like with ARGO 119 set at 120s dots, fast . It has about .1 HZ shift as xtal heats on key down. There is also a smaller longer term shift as the shack heating system cycles. The transmiter is Ropex with xtal mounted on perf board with a trimmer cap. I measure the frequency at about 136,744.6HZ. The few nights that I have looked for and copied signals from across the pond, the signals are there for 1/2 hr to a little over 1 hr with the longer times early in the night. Sandy WB5MMB -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/jpeg Size: 10476 bytes Desc: not available Url : http://atanasoff.rf.org/pipermail/lf/attachments/20010207/ffac97a7/attachment.jpeg From akestelo at bellatlantic.net Wed Feb 7 22:15:29 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:44 2003 Subject: [Lf] Re: LF: AMRAD Beacon References: <01C09150.9C612FC0.esanders@erols.com> Message-ID: <3A820F50.140848B8@bellatlantic.net> Nan and Sandy Sanders wrote: > Here is what the amrad beacon looks like with > ARGO 119 set at 120s dots, fast . It has > about .1 HZ shift as xtal heats on key down. It reminds me of one of my first transmitters: a ARC-5 "Command Set" that sounded "tuwee-ty-tuwee-ty" Ahh, nostalgia... Andre' N4ICK From akestelo at bellatlantic.net Wed Feb 7 22:22:55 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:44 2003 Subject: [Lf] Loop theory article and VLF news] Message-ID: <3A82110E.8ACD79E6@bellatlantic.net> Marco Bruno IK1ODO wrote: > Hi all, > > I published a work on loop antenna theory and some construction ideas > on Renato Romero, IK1QFK, web site http://www.vlf.it > > Opinions, suggestions, improvements and so on are welcome - Renato > will be happy to host them. We intend to open a technical section of the > site, in the "OpenLab" spirit. > > Also, we have a new contribution by Trond Jacobsen on Russian 82 Hz > emissions for the submarine fleet. > > And more is being prepared - stay tuned! > > 73 - Marco IK1ODO > > Marco Bruno - IK1ODO > spin.elec@tiscalinet.it > > SPIN Electronics - www.spin-it.com From akestelo at bellatlantic.net Thu Feb 8 18:53:58 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:45 2003 Subject: [Lf] [Fwd: LF: ARRL LF news and my LF shack] Message-ID: <3A833195.565961ED@bellatlantic.net> john sexton wrote: > Hi Dexter, > Vy interesting to read your article and see your shack - a lot of kit there! > A couple of points though. The name is John not Jim. More importantly Sandy, > WB5MMB, says that the line at 136.750 is not the WA2XTF beacon. He measured > the beacon at 136.7446 and sent a jpg showing the effects of the crystal > temperature change during keying. > Tonight I am monitoring 136.7446 and seeing a line at 136.74475. However it > doesn't show the cyclic change reported by Sandy. > It is now 22.46 and I will leave it monitoring until 08.00 tomorrow and let > you know what I see. > I have a Loran line at 136744.8993 Hz, which I have identified earlier from > a wider view and so can be very precise about the frequency, at least to .01 > Hz. > Vy 73, John, G4CNN > > _______________________________________________________ > Send a cool gift with your E-Card > http://www.bluemountain.com/giftcenter/ From akestelo at bellatlantic.net Thu Feb 8 18:58:53 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:45 2003 Subject: [Lf] Re: LF: ARRL LF news and my LF shack References: <3A82C8BB.E6CBDFF7@att.net> Message-ID: <3A8332BC.39E7E0E7@bellatlantic.net> Kudos, Dexter, and an excellent "plug" for our LF allocations :-) Keep up the good work Andre' N4ICK Dexter McIntyre W4DEX wrote: > A picture of my LF shack and recent LF news can be seen at: > > http://www.arrl.org/news/stories/2001/02/06/2/?nc=1 > > Dexter, W4DEX From akestelo at bellatlantic.net Fri Feb 9 08:34:46 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:45 2003 Subject: [Lf] Re: LF: ARRL News Story References: <3A83E830.5192.C534B3@localhost> Message-ID: <3A83F1F5.C9BA8B40@bellatlantic.net> Mike Dennison wrote: > It has been pointed out, quite correctly, that the ARRL story about > LF operating has errors in it. > In defense of my fellow journalists, I will say that given limited > resources it is inevitable that some errors will creep into any > article.[...] Compared to the incredible inaccuracies, and outright fabrications that one reads in the regular press, and watches on TV, I would say I am very impressed with the quality of information I derive from reading QST and RadCom. Keep up the good work, 73 Andre' N4ICK From akestelo at bellatlantic.net Sat Feb 10 08:19:32 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:45 2003 Subject: [Lf] Re: LF: G3LDO & M0BMU Copied Plymouth, MA References: <3.0.3.32.20010210054251.0158a710@pop.netzero.net> Message-ID: <3A853FE3.C91D995D@bellatlantic.net> It would appear that more and more people on this side of the pond are actually seeing things ... Kudos to Jonathan :-) Andre' N4ICK Jonathan Jesse wrote: > Hello, > Copied what appears to be both G3LDO and M0BMU at 0424 today. > [...] > 73, > Jon W1JHJ Plymouth, MA FN41qw > http://geocities.com/ws1k.rm From akestelo at bellatlantic.net Sun Feb 11 14:25:46 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:45 2003 Subject: [Lf] [Fwd: LF: List of transatlantics] Message-ID: <3A86E73A.DB355186@bellatlantic.net> "mike.dennison" wrote: > I have trawled through the archives and found that 11 different stations > have successfully transmitted across the Atlantic on 136kHz: 7 Gs, 1 GM, 1 > OK and 2 VEs. They have been received by 22 different stations: 4 VEs, 4 Ws, > 9 Gs, 1 PA, 1 I, 1 ON, 1 DL and 1 OH. This is an impressive record so far > this season when only a year ago there were still people arguing that it > couldn't be done. > > If you have received anyone, or been received, across the pond and you are > not on this list, please let me know. I will keep a record on my web site. > > The list is as follows (transmitting station first): > > G0MRF > VE1ZJ > G3AQC > VE2IQ, VA3LK, W1JHJ, W4DEX, WB5MMB > G3LDO > VE1ZJ, W1JHJ, W3EEE > G3XDV > VE1ZJ > G3XTZ > VE1ZJ, W3EEE, WB5MMB > G3YXM > VE1ZJ > M0BMU > VE1ZJ, VE2IQ, W1JHJ, W4DEX, WB5MMB > MM0ALM > VE1ZZ > OK1FIG > VE1ZJ, VE1ZZ > VA3LK > NL9222, G3NYK, G3XDV, G4JNT, IK1ODO, M0BMU, ON7YD > VE1ZZ > DK8KW, G0MRF, G3AQC, G3LDO, G3NYK, G3XDV, G3YXM, G4CNN, M0BMU, > ON7YD, OH9UFO > > =========== > Mike, G3XDV From akestelo at bellatlantic.net Sun Feb 11 18:51:58 2001 From: akestelo at bellatlantic.net (Andre' Kesteloot) Date: Thu Jul 3 13:43:46 2003 Subject: [Lf] GPS-Disciplined BPSK] Message-ID: <3A87259D.AE4C8EA5@bellatlantic.net> Bill de Carle wrote: > Hello everyone, > > It has long been recognized that establishing bit-sync and frame-sync > is difficult with current implementations of BPSK whenever there is > marginal copy and the signal only comes up out of the noise for a few > seconds at a time. We have to look at the signal for a long time to > synchronize and by then it may be too late to copy any actual data > because the signal has faded out. Clearly it would be a major advantage > if we could obtain the clocking and framing information by other means. > If both the Tx and Rx know precisely what time it is and can agree on a suitable standard transmitting schedule the problem is solved. > > I propose to use GPS and the following transmission protocol: > > Regardless of where a station is in the world, he will transmit his > BPSK frames synchronously according to a UTC time reference grid. This > will work for all speeds and encoding modes. The rule I'm using is > to simply assume the transmissions started with the first bit of a > frame at midnight UTC and have continued uninterrupted since that time. > If the Rx knows the speed and mode (i.e. ET1, ET2, ET3) - he can calculate > where the Tx is in its frame, when each bit starts and stops, etc. based > only on his knowledge of the present UTC instant. Given an estimate of > the distance the signal has to travel the Rx can then expect to receive > synchronous phase transitions at precisely-known instants in time. > > The transmitter's job is to put out his signal according to the above > rule. For example, at MS1875 (1.875 seconds per bit), and ET3 (32 bits > per transmitted frame), each frame will take exactly 1 minute to send, > and the first bit of every frame will start exactly on the minute boundary. > > The receiver's job is to know the time, know the distance from the > station he's trying to receive, and to expect the first bit of each > frame to arrive starting a few milliseconds after it was transmitted. > > With this arrangement multiple receivers at various distances can concurrently monitor the same transmitter. I am presently testing a GPS-disciplined version of AFRICAM that uses this protocol. > > The only real requirement is a GPS receiver with a 1-PPS output good to > within a few microseconds of UTC. This output is inverted and fed > into the "Ring Indicator" input of a serial port. The serial port has > something called a TERI (Trailing Edge Ring Indicator) interrupt, which > gets our 1 PPS signal into the PC with good time accuracy. If you are > using Sound Card audio input, you *may* connect the GPS receiver's > standard 4800-baud NMEA-sentence output to AFRICAM's serial port; that > way the UTC gets set automatically. If you're using a Sigma-Delta board > for audio digitization, it must have the serial port. But you can still > input the 1PPS GPS signal on the RI pin. Then you'll have to synchronize > AFRICAM's UTC clock by listening to WWV's ticks. It's quite easy. > Ring Indicator (RI) is on pin 9 of a DB9 connector, pin 22 of a DB25. > > If AFRICAM detects a 1 PPS input it automatically calibrates the CPU's > internal Timer-0 clock continuously against the GPS reference and uses it > for timing. It will also tell you the exact sampling rate of your sound > card if you're interested. > > There is an extra position for the AUTOTRACK switch: EXT (external sync). > That's for bit-synchronization. And you may specify a SYNC time of "-1" > which means we calculate where the startbit is based on absolute time > instead of trying to extract it from the incoming data. All the old > functions of AFRICAM are still available and you can use them for copying > GPS-disciplined BPSK if you don't have a GPS receiver handy. > > The new AFRICAM also has the means to *transmit* short (1 line) test > messages over and over until a certain time of day is reached. These > transmissions use the RTS line to BPSK-modulate a carrier and the DTR > line as a push-to-talk to key up the transmitter, same as COHERENT/AFRICA. > Transmission only works in GPS-disciplined mode however. > > There are separate user-set parameters for transmit advance and receive > delay time. Resolution is to the nearest millisecond. Transmit advance > causes keying to occur a few milliseconds earlier than the correct time > to allow for delay through transmitter circuits (which can be quite a > few milliseconds) so the signal gets "launched" at just the right time. > The receive delay accounts for delays in the receiver and of course the > propagation delay. Estimate 5 microseconds per mile or 1 millisecond for > every 200 miles. > > Initial results look very promising but I want to run some tests before > posting the program to my website. If anyone out there is already set up > with a 1 PPS GPS signal and wishes to participate in these tests, please > let me know by e-mail. > > Best, > Bill VE2IQ From esanders at erols.com Mon Feb 12 21:44:50 2001 From: esanders at erols.com (Nan and Sandy Sanders) Date: Thu Jul 3 13:43:46 2003 Subject: [Lf] Sun night report Message-ID: <01C0953D.092C0F40.esanders@erols.com> Saw CT1DRP starting about 23:00 Sun until about 01:45 Mon very strong peak "1DRP". ARGO smeared the elements together then gone until 02:20 it came back 1 HZ higher in frequency until 07:40 with very strong peaks and fades. I also saw several lines that I could not pull call signs out of except G3LDO from 04:00 until 06:54 with peaks and fades. Sandy WB5MMB From esanders at erols.com Mon Feb 12 21:44:50 2001 From: esanders at erols.com (Nan and Sandy Sanders) Date: Thu Jul 3 13:43:46 2003 Subject: [Lf] Sun night report Message-ID: <01C0953D.092C0F40.esanders@erols.com> Saw CT1DRP starting about 23:00 Sun until about 01:45 Mon very strong peak "1DRP". ARGO smeared the elements together then gone until 02:20 it came back 1 HZ higher in frequency until 07:40 with very strong peaks and fades. I also saw several lines that I could not pull call signs out of except G3LDO from 04:00 until 06:54 with peaks and fades. Sandy WB5MMB From andre.kesteloot at ieee.org Tue Feb 13 18:54:14 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:46 2003 Subject: [Lf] lf transatlantic exchange of information] Message-ID: <3A89C926.B8F6F30@ieee.org> John Currie wrote: > Hi All, An exchange of information has taken place across the > atlantic. I acted as Jack VE1ZZ's receiving station, Just like CFH > transmits from one sight but receives from another. Peter, G3ldo and > Jack VE1ZZ had a QSO, sort of ! > > Jack transmitted on 136.5 kHz > Peter heard Jack and he called VE1ZZ signed G3LDO and sent Jack a > "M" > signal report > I heard Peter and communicated the report and call identification > information via > link on 3530 kHz to Jack . I also gave Jack a signal > report to > communicate to Peter. Jack sent Peter RRR and "O". We > started > 2105. By now condx were improved. > Peter sent R and Jack sent R > Jack always transmitted to Peter on 136.5 kHz with 3 second > dots. > Peter always answered on 135.921 kHz with 10 second dots. > The contavt ended at 2237Z > > Congratulations to Peter and Jack > Screen shots will follow > 73 de John VE1ZJ From andre.kesteloot at ieee.org Tue Feb 13 18:55:01 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:46 2003 Subject: [Lf] LF: VE1ZZ/VE1ZJ] Message-ID: <3A89C955.2639F0D6@ieee.org> Peter Dodd wrote: > I have just had an interesting QRSS QSO with Jack, VE1ZZ. My transmit > frequency was 135.920 and Jack was on 136.501. I used 10s dots, John 3s dots. > > My QRSS signal was received by John, VE1ZJ and relayed via 80m to VE1ZZ. > > VE1ZZ was first received at 2200 and although quite strong was only R 'M'. > > I sent this report to VE1ZZ and with no noticeable delay got an > acknowledgement. > > By this time the signals had increased to R 'O' and this was sent > with the final acknowledgement. > > My special thanks go to John for making the QSO possible. > > I will send .jpgs to Dave Pick as soon as I have them together. > > > > -- > Regards, Peter, G3LDO > > From andre.kesteloot at ieee.org Thu Feb 15 09:20:11 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:46 2003 Subject: [Lf] [Fwd: LF: LDO > ZJ > ZZ a two-way?] Message-ID: <3A8BE59B.EFBFDBB9@ieee.org> Mike Dennison wrote: > I have been giving some thought to whether I personally regard the > recent G3LDO/VE1ZJ/VE1ZZ QSO to be a two-way. > > My initial reaction was to say that because there was a relay station > that did more than just relay - he decoded the spectrogram - this did > not constitute a two-way with remote receive. > > I still think it was not a two-way between VE1ZZ and G3LDO, but was > it a two-way transatlantic QSO? There was no 'assistance' on either > of the transatlantic paths, only when it reached VE, and the required > callsigns and previously unknown information (report) crossed the > Atlantic in both directions, and ended up with the same two stations. > I think Peter, John and Jack can claim the first two-way, though > they have not yet. > > This looks like it might be an interesting question for the Bobek > Trophy adjudicators in RSGB (not me), DARC and AMRAD. > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From andre.kesteloot at ieee.org Thu Feb 15 11:27:09 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:47 2003 Subject: [Lf] Insulator problems] Message-ID: <3A8C035D.6FD1E966@ieee.org> James Moritz wrote: > Dear LF group, > > I notice a few people have been having problems with insulators > melting/cracking lately. I had problems with my insulators until I > fitted some corona rings. What seems to happen when you try to > put a lot of power into a small antenna is that corona discharges > take place at the ends of the wire and at sharp bends where > insulators are attached, where the radius of curvature of the > conductor is small, and the potential gradient large. The heat > generated either melts, cracks or sets fire to the insulators. > > So I have fitted the corona rings, which are just hoops of stiff wire > about 100mm in diameter, to the "hot" ends of the 3 insulators (2 > plastic and 1 ceramic) on my antenna wire. This has eliminated any > detectable discharges from the wire, even when operating at full > power in heavy rain. The rings are electrically connected to the > wire. The "cold" ends of the insulators are supported with non- > conducting rope in my system, but with wire halyards you would > want a corona ring on both ends of the insulator. It is a simple mod > to make, and has made all the difference to my antenna, so might > be worth a try if you are having problems. > > Cheers, Jim Moritz > 73 de M0BMU From fgentges at mindspring.com Thu Feb 15 22:11:10 2001 From: fgentges at mindspring.com (Frank Gentges =?iso-8859-1?Q?K=D8BRA?=) Date: Thu Jul 3 13:43:47 2003 Subject: [Lf] AMRAD January LF Field Day Message-ID: <5.0.2.1.0.20010215220624.02bb3070@pop.mindspring.com> AMRAD went out in mid-January to have an LF field day. For details see . I sure wish the propagation was up to what we have seen the past two weeks. We would have probably copied the European stations. Oh well....we had fun and learned some good things. Frank Frank Gentges K?BRA fgentges@mindspring.com From andre.kesteloot at ieee.org Sat Feb 17 07:11:53 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:47 2003 Subject: [Lf] LF book errata] Message-ID: <3A8E6A88.C33372B@ieee.org> g3ldo wrote: > The Addendum and Errata to the LF book has been updated and is on > http://web.ukonline.co.uk/g3ldo > > In particular the S/W for the 3-M impedance measuring box can be downloaded. > > Regards, > Peter, G3LDO > > From andre.kesteloot at ieee.org Mon Feb 19 10:03:54 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:47 2003 Subject: [Lf] It's L at the top Message-ID: <3A9135DA.1C549E30@ieee.org> Mike Dennison wrote: > On Sunday I increased the inductance at the top of my mast. I > replaced 3mH of Litz wire with 7mH of ordinary wire. This made the > antenna almost self-resonant. In fact, I needed a 6800pF capacitor > (very heavy duty oil-filled, from the Puckeridge Decca site) in series > with my 0.5mH variometer to tune it. > > As expected, the current dropped - from 2.7A to 2.2A - as the point > of maximum current went higher up the mast. > > There have been no measurements yet, but initial results seem > good. I received the best ever reports from GW (599), GM (589) > and SM (579), and worked DJ9IE (559) who had never replied to > my calls before. > > An all-night transmission using 30s dots on 135.9235kHz did not > seem to cause any trouble, so all seems stable. > > Mike, G3XDV (IO91VT) > http://www.lf.thersgb.net From andre.kesteloot at ieee.org Mon Feb 19 14:01:39 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:47 2003 Subject: [Lf] Active antenna preamps] Message-ID: <3A916D93.18C0322E@ieee.org> James Moritz wrote: > Dear LF Group > > Congratulations to Laurie & Larry on their QSO - for those in the > Antipodes wanting to participate in G to VK and ZL tests, perhaps > now would be a good time to switch on the spectrogram software - > by the time you have successfully obtained a 136kHz allocation, > and built new transmitters and antennas, enough time might have > elapsed to receive a CQ call :-) > > Thanks to PA0SE for the info on the active antenna - this preamp > circuit is a high frequency application of the "charge amplifier" > circuit configuration, widely used with other capacitive signal > sources, such as condenser microphones and piezoelectric > transducers. Resistors of up to 5Gigohms are listed by RS > components, if you don't mind paying several pounds each. Not > sure what an FD300 diode is, but it must have very low leakage! > > For those interested in using op-amps at LF frequencies, I have > been experimenting with the Burr-Brown OPA604. Although > primarily an audio device, this is quite well suited to tuned loop pre- > amps and other high impedance, moderate bandwidth applications. > It has fairly low voltage noise, 10nV/rootHz, which is less than the > thermal noise produced by most tuned loops, and negligible current > noise. It is reasonably fast - 20MHz GBP, 25V/us slew rate, but not > really fast enough for wideband antennas. It works OK from a > single 12V supply rail. It is fairly cheap at a bit over 1GBP and > seems to resist destruction quite effectively. > > Cheers, Jim Moritz > 73 de M0BMU From andre.kesteloot at ieee.org Mon Feb 19 14:16:35 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:48 2003 Subject: [Lf] [Fwd: LF: Signalling margins and Shannon] Message-ID: <3A917113.AFFA69B9@ieee.org> Talbot Andrew wrote: > Has anyone looked at what Signal to Noise is realistically viewable > on a spectrogram display ? Assuming bandwidth equal to FFT bin size, > my few tests suggest around 10dB but it would be nice to have a more > authoritative figure to calculate with. Obviously depends on colour > palette and number of colours on the display so after a couple of > years of experience with Spectrogram and now Argo, what has anyone > found ?A back of envelope calculation on signalling capabilities using > DFCW :(Switch off now those not interested in communications theory > and working out what Could be done > <:-)-------------------------------------------------For DFCW, signal > bandwidth needs to be at least twice that of a dot interval in order > to be able to distinctly see the on-off transitions. Doubled again, > since two frequencies are involved, but some overlap of sidebands is > allowed as we can sttill se which of the frequencies is intended, so > take a total signalling bandwidth of 3 times the dot interval as being > the minimum needed. This gives a signalling rate of 1 / 3 Bit / > second per Hz (0.33 B/s/Hz) Shannon's law relates signalling rate to > Signal to Noise by :R = LOG(1 + S/N) (LOG to the base 2 and S/N in > numerical units, not dB)so for R = 0.33, signalling should be possible > (at an 'arbitrarily low' error rate) in a S/N of 0.258 = -5.8dB > (yes, negative S/N)If 10dB S/N is needed for viewing then we are > almost 16dB down on ShannonAnd this does not even allow for further > signal degradation due to multipath / fading,The only scheme I have > ever come across that reckons to get within less than 1 dB of Shannon > makes use of the very latest Turbo coding schemes now possible with > high speed DSP, coupled with continuous phase modulation (partially > related to MSK) It is / was a contender for third generation mobile > phones to increase data rate there in the congested bandwidth > available. PSK and QAM modulation sits somewhere between.Coding > :DFCW codes the alphabet into between 1 and 5 bit intervals per > character plus a gap for inter letter spacing, which, with the two > frequency level coding, equates to between 4 to 12 bits per > character. The letter frequency of plain language text coupled with > the one bit for E, two for A,N and 4 for Q, Z etc means there is > probably an average of around 5 - 6 bits per letter, which is not bad > coding efficiency - simple Baudot manages 7.5 bits / character and > PSK31 about 5.5 - 6. The very best dictionary based coding schemes, > transmitting codes to represent words or even whole phrases, can claim > 1 bit or less per letter equivalence.However, the coding efficiency > only affects the time to send the overall message since it dictates > the Total number of bits needed, not the S/N needed in which to send > it; that only dictates the rate.Andy G4JNT > > -- > The Information contained in this E-Mail and any subsequent > correspondence > is private and is intended solely for the intended recipient(s). > For those other than the recipient any disclosure, copying, > distribution, > or any action taken or omitted to be taken in reliance on such > information is > prohibited and may be unlawful. From andre.kesteloot at ieee.org Mon Feb 19 14:15:52 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:48 2003 Subject: [Lf] LF: Where next?] Message-ID: <3A9170E7.1768EABB@ieee.org> Mike Dennison wrote: > > ..................... One such candidate could be the Steve Onley's FDK. I > > know that, theoretically, PSK can have an advantage over non-coherent > > FSK, but this doesn't take into account phase distortion over very > > long paths. But I will leave to others to discuss about the pros and > > cons of the two methods. > > 73 Alberto I2PHD > > A factor that is often ignored when comparing PSK08 (for instance) > and QRSS is the difference between relying on a machine to > interpret the results and using the brain. The spectrogram-type > programs do wonderful work but the final 10dB or so is down to the > brain deciding what is a valid signal and what is not, then deciding > whether it makes sense or not. > > We really would have a winner if we can combine the obvious > theoretical advantages of using FM (or phase mod) rather than AM, > especially when noise is a significant limiting factor, with the > advantages of a display that allows the brain to add some dBs by > intelligently interpreting the result. > > For instance, how about produce a display that is the result of > subtracting the signals and noise in a given audio band, with the > signals and noise in another band of the same bandwidth. This might > provide a means of reducing the effect of wideband noise such as > static (but not random noise) on a conventional mono-frequency > transmission by subtracting the noise in the 'no-signal' band from > the band containing the signal. It might also provide a 'comparitor' > effect so that FSK signals can be better detected - for a given time > period, if the output of 'channel A' is bigger than the output of > 'channel B' then it is a binary '1'; if the other way round it is a binary > '0'.The important thing is to resist the temptation to feed this into a > machine that tries its best to work out whether it is a valid character > or not - this is the bit that the brain does better. > > Mike From andre.kesteloot at ieee.org Mon Feb 19 22:11:00 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:48 2003 Subject: [Lf] shud we move on? References: <65AECDF1F89AD411900400508BFC869F0D75CC@pdw-mail-1.dera.gov.uk> <3A9160B5.D9C9DE4D@usa.net> <002801c09acb$30ae6cf0$0a00a8c0@ThreeLakes.ca> Message-ID: <3A91E044.E1822E6F@ieee.org> hello Larry, The AMRAD LF reflector, for one, would be very glad to post strange ideas such as yours, and those of others who entertain similar way out approaches :-) 73 Andre' N4ICK ********************************** Larry Kayser wrote: > Gentlemen: > > With the completion of the TransAtlantic QSO is it time to consider moving > on? The RSGB reflector has been a wonderful and gracious host for the last > 18 months that I have been a part of it - as we seem to be entering a new > phase is it time to move onwards, to separate graciously and with good > humour and good feelings into a European Centric focus for this reflector > and the Really Really Weak Signal (RRWS) people move off and create our > mahem in some other resource? Would the RSGB consider hosting a RRWS > reflector? > > This needs to be carefully thought through - I for one am reluctant to bring > up issues about 300 second data bits simply because I know that many of the > participants on this reflector are not even happy about 30 second visual CW > bits. I also am not keen to get into discussions that I know full well are > making other users of the facility unhappy. > > For instance I saw an email today from Steve, GW4ALG that listed many LF > users in the UK and Europe that I have never had a chance to hear, many of > them obviously aural CW users. > > My question for your consideration is - should some of us move on. > > My personal quest is to head for higher performance systems, slower sending, > and regular VA3 to ZL/VK and Europe communications. I wonder who would like > to go in that direction as a specialty within the LF community. > > Discussion? > > Larry > VA3LK From andre.kesteloot at ieee.org Tue Feb 20 20:05:13 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:48 2003 Subject: [Lf] Higher L - higher ERP ??? Message-ID: <3A931448.E4FD65A8@ieee.org> Vernall wrote: > Mike and others, > > OK on the elevated loading coil. I'm not convinced that hard results > support your claims: > > > Yesterday, I reported that I had increased my mast-head > > inductance so that the antennna was almost self-resonant. The new > > coil introduced resistive losses and the current reduced, but reports > > were better than before. > > If I recall, you said that the changed current distribution was an > explanation for the reduced value of current at the feedpoint, which was > incorrect. Current is dependent on "loop resistance" at resonance. > > > Last night, Jim, M0BMU measured my field strength compared to a > > measurement taken two weeks ago. It was 0.9dB up. > > That is very similar to some tests I did some time back, at 181 kHz, with a > temporary top loading. > > > This does not account for the greatly improved reports, > > Quite so. 0.9 dB hardly shifts the S meter. > > > but it does > > show that with less current and more resistive losses, the only way > > the ERP could have increased is if the 'effective height' had > > increased. > > Yes. The net result of decreased current because of increased loop > resistance (a top loading coil necessarily needs higher inductance (more > wire) than a base loading coil) and the improved current distribution in the > vertical wire. The effective height factor is just winning out over current > reduction, by some 0.9 dB. > > >Field strength is of course directly proportional to current > > squared multiplied by effective height (h) squared. > > True for radiated power. Field strength is directly proportional to the > product of current and effective height (amp metres). > > > At last here is real evidence that the elevated coil really does > > increase the 'h' part of the equation. Several of us were sure that it > > did, and several have noticed improvements in our signals when > > using elevated coils, but the evidence has always been anecdotal. > > And still appears to be the case. The same "gain" should be observed on > transmit and receive (being wary that local noise could be different at each > end of a path). > > There is still the matter of adequately housing the elevated loading coil > and sustaining good insulation at high RF voltages. The weight of a coil > usually means it needs to be supported by a tower or mast. Antenna > modelling shows that if the vertical feed to a T antenna is near metalwork, > it caused shunt capacitance that pulls down the gain by about 1 dB. Tuning > (and re-tuning) of the loading coil is somewhat inconvenient when it up in > the air. > > One situation not amenable to modelling (with NEC-2) is when there is > clutter around the vertical wire. It seems that clutter causes > disproportionate losses from "soakage" as the high field strength part of > the wire rises above ground. Some experimenters have reported significant > improvement by relocating the "upwire" to being in a clearer environment. A > similar effect would arise with an elevated loading coil, as the potential > on the "upwire" is considerably lower than for a base loading coil > installation. However, all of these environmental factors should show up in > impedance data and gain measurements. > > I have observed the construction technique a number of LF NDB stations, from > visits and photographs. None have elevated loading coils. All have clear > sites. > > I'm not against experimentation and developing better antennas that fit in > our back yards. > > 73, Bob ZL2CA From andre.kesteloot at ieee.org Tue Feb 20 20:05:13 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:48 2003 Subject: [Lf] Higher L - higher ERP ??? Message-ID: <3A931448.E4FD65A8@ieee.org> Vernall wrote: > Mike and others, > > OK on the elevated loading coil. I'm not convinced that hard results > support your claims: > > > Yesterday, I reported that I had increased my mast-head > > inductance so that the antennna was almost self-resonant. The new > > coil introduced resistive losses and the current reduced, but reports > > were better than before. > > If I recall, you said that the changed current distribution was an > explanation for the reduced value of current at the feedpoint, which was > incorrect. Current is dependent on "loop resistance" at resonance. > > > Last night, Jim, M0BMU measured my field strength compared to a > > measurement taken two weeks ago. It was 0.9dB up. > > That is very similar to some tests I did some time back, at 181 kHz, with a > temporary top loading. > > > This does not account for the greatly improved reports, > > Quite so. 0.9 dB hardly shifts the S meter. > > > but it does > > show that with less current and more resistive losses, the only way > > the ERP could have increased is if the 'effective height' had > > increased. > > Yes. The net result of decreased current because of increased loop > resistance (a top loading coil necessarily needs higher inductance (more > wire) than a base loading coil) and the improved current distribution in the > vertical wire. The effective height factor is just winning out over current > reduction, by some 0.9 dB. > > >Field strength is of course directly proportional to current > > squared multiplied by effective height (h) squared. > > True for radiated power. Field strength is directly proportional to the > product of current and effective height (amp metres). > > > At last here is real evidence that the elevated coil really does > > increase the 'h' part of the equation. Several of us were sure that it > > did, and several have noticed improvements in our signals when > > using elevated coils, but the evidence has always been anecdotal. > > And still appears to be the case. The same "gain" should be observed on > transmit and receive (being wary that local noise could be different at each > end of a path). > > There is still the matter of adequately housing the elevated loading coil > and sustaining good insulation at high RF voltages. The weight of a coil > usually means it needs to be supported by a tower or mast. Antenna > modelling shows that if the vertical feed to a T antenna is near metalwork, > it caused shunt capacitance that pulls down the gain by about 1 dB. Tuning > (and re-tuning) of the loading coil is somewhat inconvenient when it up in > the air. > > One situation not amenable to modelling (with NEC-2) is when there is > clutter around the vertical wire. It seems that clutter causes > disproportionate losses from "soakage" as the high field strength part of > the wire rises above ground. Some experimenters have reported significant > improvement by relocating the "upwire" to being in a clearer environment. A > similar effect would arise with an elevated loading coil, as the potential > on the "upwire" is considerably lower than for a base loading coil > installation. However, all of these environmental factors should show up in > impedance data and gain measurements. > > I have observed the construction technique a number of LF NDB stations, from > visits and photographs. None have elevated loading coils. All have clear > sites. > > I'm not against experimentation and developing better antennas that fit in > our back yards. > > 73, Bob ZL2CA From andre.kesteloot at ieee.org Tue Feb 20 20:05:13 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:49 2003 Subject: [Lf] Higher L - higher ERP ??? Message-ID: <3A931448.E4FD65A8@ieee.org> Vernall wrote: > Mike and others, > > OK on the elevated loading coil. I'm not convinced that hard results > support your claims: > > > Yesterday, I reported that I had increased my mast-head > > inductance so that the antennna was almost self-resonant. The new > > coil introduced resistive losses and the current reduced, but reports > > were better than before. > > If I recall, you said that the changed current distribution was an > explanation for the reduced value of current at the feedpoint, which was > incorrect. Current is dependent on "loop resistance" at resonance. > > > Last night, Jim, M0BMU measured my field strength compared to a > > measurement taken two weeks ago. It was 0.9dB up. > > That is very similar to some tests I did some time back, at 181 kHz, with a > temporary top loading. > > > This does not account for the greatly improved reports, > > Quite so. 0.9 dB hardly shifts the S meter. > > > but it does > > show that with less current and more resistive losses, the only way > > the ERP could have increased is if the 'effective height' had > > increased. > > Yes. The net result of decreased current because of increased loop > resistance (a top loading coil necessarily needs higher inductance (more > wire) than a base loading coil) and the improved current distribution in the > vertical wire. The effective height factor is just winning out over current > reduction, by some 0.9 dB. > > >Field strength is of course directly proportional to current > > squared multiplied by effective height (h) squared. > > True for radiated power. Field strength is directly proportional to the > product of current and effective height (amp metres). > > > At last here is real evidence that the elevated coil really does > > increase the 'h' part of the equation. Several of us were sure that it > > did, and several have noticed improvements in our signals when > > using elevated coils, but the evidence has always been anecdotal. > > And still appears to be the case. The same "gain" should be observed on > transmit and receive (being wary that local noise could be different at each > end of a path). > > There is still the matter of adequately housing the elevated loading coil > and sustaining good insulation at high RF voltages. The weight of a coil > usually means it needs to be supported by a tower or mast. Antenna > modelling shows that if the vertical feed to a T antenna is near metalwork, > it caused shunt capacitance that pulls down the gain by about 1 dB. Tuning > (and re-tuning) of the loading coil is somewhat inconvenient when it up in > the air. > > One situation not amenable to modelling (with NEC-2) is when there is > clutter around the vertical wire. It seems that clutter causes > disproportionate losses from "soakage" as the high field strength part of > the wire rises above ground. Some experimenters have reported significant > improvement by relocating the "upwire" to being in a clearer environment. A > similar effect would arise with an elevated loading coil, as the potential > on the "upwire" is considerably lower than for a base loading coil > installation. However, all of these environmeX-Mozilla-Status: 0009ow up in > impedance data and gain measurements. > > I have observed the construction technique a number of LF NDB stations, from > visits and photographs. None have elevated loading coils. All have clear > sites. > > I'm not against experimentation and developing better antennas that fit in > our back yards. > > 73, Bob ZL2CA From andre.kesteloot at ieee.org Sun Feb 25 08:16:37 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:49 2003 Subject: [Lf] G3NYK/PA0SE-bridges] Message-ID: <3A9905B4.D0BE38B4@ieee.org> Dick Rollema wrote: > Uwe, DJ8WX, wrote: > > > Dick, where did you get that Wayne-Kerr-B.601-bridge from ? > > could one purchase it somewhere? > > I have two Wayne Kerr admittance bridges: > > Type B601: 15 kHz - 15 MHz > > Type B801: 1 MHz - 100 MHz > > But my home made noise bridge performs almost as well. I took great care to > make it frequency independent and succeeded in doing so up to 30 MHz. > > I bought the Wayne Kerr bridges for little money in a war surplus shop and > at a rally of the Dutch Society for the History of Radio. > You can usually pick up older type of test equipment at rallies at low > prices because most present day amateurs are of the "Steckdose" type > and are not at all interested in measuring gear. > > I tested my bridges by connecting them to a 3 m long piece of RG213 type 50 > ohm coax that was terminated by a 50 ohm resistor (actually two 100 ohm > resistors in parallel). That produces a standing wave ratio of 2 in the > cable. The impedance at the input of the cable was measured at a range of > frequencies up to 30 MHz. When the results are plotted on a RX-diagram they > must lie on a circle; the one for SWR = 2. For the Wayne Kerr bridges this > was indeed the case. But the deviation from the circle was also very small > for my home made bridge. Only 30 MHz near the measured impedances tended to > lie inside the circle for all three bridges. This was caused by the loss in > the coax that made the SWR < 2 at the input of the cable. > > > BTW.Dick, I just answered ur cq on 136 kHz. sri u did not hear my signal. > u > > where 559 in j043sv (ant: inverted V with 340m es 400m lws). > > A pity I did not hear you. Perhaps some other time? > > 73, Dick, PA0SE From andre.kesteloot at ieee.org Sun Feb 25 08:24:55 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:49 2003 Subject: [Lf] [Fwd: LF: Measuring resistance of aerial system] Message-ID: <3A9907A6.97CDD923@ieee.org> Dick Rollema wrote: > To All from PA0SE To measure the total resistance of my aerial system > I can use a Wayne Kerr admittance bridge type B.601. To do that the > bridge must be connected to a generator and detector.A method > involving less work is using my homemade impedance bridge with > built-in noise source and battery and using the 137kHz receiver as > detector. This gadget measures R up to 270 ohms and X as a capacitance > between -150pF and +150pF in parallel with the R-control. On 137kHz > the X-control range is too small and I leave it at the zero position. > The null is found by varying the R-control of the bridge and the > vacuum capacitor tuning the aerial system. The null is very sharp when > the receiver is switched to a narrow passband.The calibration marks on > the R-control are at multiples of 10 ohm. But the R-value can be read > with much better accuracy by afterwards measuring the resistance of > the R-control pot with a digital multimeter. There is no need to open > the box of the bridge for this; the resistance can be measured at the > port for the unknown. After subtracting the loss resistance of the > loading coil I find for the earth resistance: July 1999 : 28 > ohmFebruary 2000: 33 ohmFebruary 2001: 32 ohm Summer 2000 I have > measured even lower values but I did not put them on paper. It amazes > me that the resistance is lower in summer than in winter. I had > expected the opposite.There are no trees near the aerial. When it > rains or in fog the resistance rises considirable, as indicates by the > aerial current dropping by up to 25%. Could that be due to water > particles being heated in the field around the aerial? Or is it only > caused by increased leakage via the aerial insulators and the > feed-in? 73, Dick, PA0SE -------------- next part -------------- An HTML attachment was scrubbed... URL: http://atanasoff.rf.org/pipermail/lf/attachments/20010225/56634f0e/attachment.html From andre.kesteloot at ieee.org Sun Feb 25 08:29:58 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:50 2003 Subject: [Lf] Higher L - higher ERP] Message-ID: <3A9908D5.B45B0223@ieee.org> Brian Rogerson wrote: > Hi Rik, > > I have been following the folklore around antennas since I joined the > reflector and have many printed out and and in a folder. I am currently > trying to make sense of my own situation. > > My antenna is a conventional Marconi T, very similar to the ones I see > at the Portuguese Naval Radio station which I pass quite frequently. > With 23m overall height, the top is an 80m folded dipole and the vertical > is a 300ohm quad transmission line, all constructed in 2.5mm aluminium > wire. I think you wrote a little note on alumium wire. Unfortunately I > have many trees and the vertical was shaddowed closely up to about 20m > with separation of only 2m in places. For 136 all four wires of the feeder > are shorted together and the system is resonated by by a coil with spaced > turns also in aluminium wire. > > Under these conditions I measured the feed point resistance in the region > of 140 to 150 ohms using a noise bridge and managed about 0.8-0.9A aerial > current using the appropriate tapping on the matching transformer. The > output of the tx was 200V peak to peak or about 100W. Ignoring cable > losses R=100/(0.85)^2=138ohms and there is rough confirmation between > the measurements. I have had the trees reduced in height. The new > measurement for feedpoint resistance is around 70ohms with a very > wide flat minima on the noise bridge. The tx is now one module of the > Decca with 54v ht and 8A or 432W input when transmitting. I measured > 400W into a 50ohm dummy load so efficiency is 92.6%! The best match > on the matching transformer is between 40 and 50ohms. Aerial current > is now 3A so R=400/(3)^2=44ohm and there is a big difference between > noise bridge and power measurement. I cannot think why. Of course > when I was carrying out the last measurements everything was soaking as > it had been raining for months and maybe this is the answer. I shall have > to repeat the measurements when everything has thoroughly dried out. > > This may give you another set of data for European soil and of course > any comments would be gratefully received. > > 73, Brian > > At 09:20 23/02/01, you wrote: > >Hi John, > > > >I believe that the 'basic rule' with an elevated loading coil is that the > >current remains constant from the bottom end (feeding point) up to the coil > >and will drop linear from the coil toward the end of the antenna. > >So if you have the coil at the top of the vertical section you will get a > >constant current over this section, the same that you would get with a > >infinite topload (that is Andy's theory in other words ..). > > > >But I am 'triggered' by something else : > > > >>I base this on measurements under our US no-license regulations at 1750 > >>meters. One of my last attempts at operation from this qth, surrounded by > >>trees, resulted in 200ma at the base and roughly 150 to 170ma entering the > >>top hat with base tuning only. (I say "roughly" because I could only get > >>myself to about half the height of the vertical run and had to sight > through > >>binoculars. Also, my notes have long since gone missing, so I'm having to > >>depend a lot on my write-only memory. This was all with a vertical run > of a > >>little over 8m and a top radius a little less than 7m.) > > > >At a rather poor location (trees) you manage to get 0.2A with 1W input, > >what means a loss resistance of less than 25 Ohm. > >When I read the results similar of other lowfers (antenna currents up to > >0.4A, what would mean a loss of only 6 Ohm) I am always suprised by the low > >losses they achieve. > >>From what I know from European stations on 136kHz the losses go from +/- 30 > >Ohm (those with a close-to-perfect location) to 150 Ohm at a poor location. > > > >So either : > >1. ground losses are very frequency dependent > >2. American soil is so much better (for LF) than European soil > >3. the conversion rate from American Watt to European Watt is not 1/1 > > > >Assuming that : > >1. most lowfers stick to the 1 Watt input rule > >2. soil can be different, but not over an entire continent > >I believe that ground loss must be very frequency dependent > > > >73, Rik ON7YD > > > > > > > > > 73 Brian CT1DRP IN51QD 41 09 58N 08 39 11W > http://homepage.esoterica.pt/~brian From andre.kesteloot at ieee.org Sun Feb 25 18:01:00 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:50 2003 Subject: [Lf] Worth looking at ... Message-ID: <3A998EAC.B40674F7@ieee.org> Assuming you are interested in the working of antennas, you might go visit http://members.aol.com/jnrstanley/mainpres.htm 73 Andre' N4ICK From vdetomasi at tiscalinet.it Mon Feb 26 19:38:56 2001 From: vdetomasi at tiscalinet.it (Vittorio De Tomasi) Date: Thu Jul 3 13:43:50 2003 Subject: [Lf] Grounding Message-ID: <3A9AA2BF.AAE62851@tiscalinet.it> Another discussion about the use of bentonite to decrease ground resistivity started on HCDX mailing list. There is an interesting web page about this at http://www.hard-core-dx.com/nordicdx/antenna/ground/bentonite.html . HCDX mailing list can be searched starting from the hard-core DX home page at http://www.hard-core-dx.com . vy 73 Vittorio ik2czl -- ************************************************************************* Vittorio De Tomasi ik2czl@amsat.org http://www.weaksignals.com "Wir muessen wissen; wir werden wissen" (David Hilbert) From andre.kesteloot at ieee.org Mon Feb 26 21:57:08 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:50 2003 Subject: [Lf] Grounding] Message-ID: <3A9B1784.CEECD2FD@ieee.org> Vittorio De Tomasi wrote: > Another discussion about the use of bentonite to decrease ground > resistivity started on HCDX mailing list. > There is an interesting web page about this at > http://www.hard-core-dx.com/nordicdx/antenna/ground/bentonite.html . > HCDX mailing list can be searched starting from the hard-core DX home > page at http://www.hard-core-dx.com . > > vy 73 > > Vittorio ik2czl > > -- > ************************************************************************* > Vittorio De Tomasi ik2czl@amsat.org > http://www.weaksignals.com > > "Wir muessen wissen; wir werden wissen" (David Hilbert) > > _______________________________________________ > lf mailing list > lf@amrad.org > http://www.amrad.org/mailman/listinfo/lf From andre.kesteloot at ieee.org Mon Feb 26 23:10:44 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:50 2003 Subject: [Lf] Antenna measurements/losses/insulators] Message-ID: <3A9B28C3.9EACA0E@ieee.org> James Moritz wrote: > Dear LF group, > > Re- antenna loss resistance: A basic difficulty with direct > impedance measurement of an LF antenna is that the loss > resistance is much smaller than the magnitude of the reactance. > For example, an antenna with R(loss) = 50ohm, C = 500pF, has a > capacitive reactance of 2.3405kohm. The magnitude of the > combined impedance is 2.341kohm, and the phase angle > 88.8degrees, so quite close to that of the pure capacitance. A > bridge will produce an accurate measurement of the capacitance > component, but much larger errors will occur in measuring the > resistive component, which is only a few percent of the total > impedance. Even a very good bridge will struggle to get anything > more than a rough figure for the resistance. > > A better way to measure loss resistance is to cancel out the > capacitive reactance of the antenna with a series loading coil (ie. > tune it to resonance), and then measure the remaining resistance, > as done by PA0SE. > > A seperate measurement is then required to determine the loss > resistance of the loading coil. This can be done by resonating the > loading coil with a low-loss capacitor in place of the antenna, and > measuring the resistance again. > > Re: antenna losses - I use my "Scopematch" tuning aid (see LF > Handbook and errata) to continuously monitor the antenna > resistance while transmitting. I also see the resistance go up (and > the capacitance, to a smaller extent) when it is raining. The change > occurs practically instantly when the rain starts, and is usually > about 10 - 20%. I don't think wet insulators can be responsible - > estimating the additional power loss at a couple of hundred watts in > my case, they should dry themselves out quite fast! > > I don't know why rain has so much effect, but my favorite theory for > the major cause of loss resistance at the moment is that it is > caused mainly by dielectric losses in the ground, where the electric > field of the antenna penetrates to some depth at LF. This is > contrary to the conventional view that the major losses are due to > the resistance of the ground system. I don't think there is really a > contradiction, just that amateur antennas have relatively high > dielectric losses because they are smaller than conventional LF > antennas. A bit of thought shows that a predominance of dielectric > loss would explain lower loss resistance at higher frequency, and > G3AQC's "footprint" effects, among other things. > > Re: Insulators - Although better insulators, ie big glass or ceramic > ones would help prevent the antenna catching fire or falling down, > they would not actually stop corona discharge from taking place. > This is a function of the field gradient around the antenna wires, > and so needs attention to the conductors more than the insulators, > hence the usefulness of corona rings. Prevention of corona is also > a good idea from the QRM point of view. > > Cheers, Jim Moritz > 73 de M0BMU From andre.kesteloot at ieee.org Mon Feb 26 23:11:14 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:51 2003 Subject: [Lf] [Fwd: LF: Antenna measurements/losses/insulators] Message-ID: <3A9B28E2.687F60EE@ieee.org> WarmSpgs@aol.com wrote: > In a message dated 2/26/01 10:28:03 AM Eastern Standard Time, > j.r.moritz@herts.ac.uk writes: > > << ...my favorite theory for > the major cause of loss resistance at the moment is that it is > caused mainly by dielectric losses in the ground, where the electric > field of the antenna penetrates to some depth at LF. This is > contrary to the conventional view that the major losses are due to > the resistance of the ground system. I don't think there is really a > contradiction, just that amateur antennas have relatively high > dielectric losses because they are smaller than conventional LF > antennas. A bit of thought shows that a predominance of dielectric > loss would explain lower loss resistance at higher frequency, and > G3AQC's "footprint" effects, among other things. >> > > For what it's worth, Jim's theory is entirely consistent with (pardon the > expression) commercial practice and theory. I agree that there is no real > contradiction. What we as amateurs lump together under the term "ground > loss" are actually a number of factors, and at LF the dielectric properties > of the ground certainly are a major component; perhaps _the_ major component > at 136kHz. > > The soil conductivity charts we use to predict groundwave coverage at MF over > North America differ greatly from the ones used at LF. Skin depth is a major > reason usually cited for this discrepancy, along with different assumptions > about dielectric constant. The interaction between the ground system and > losses in the earth extend to a greater depth, where subsoil and rock > properties may diverge widely from those near the surface. Thus, not only is > the apparent conductivity different for MF and LF at any given location, but > the shapes of the conductivity contours don't bear much resemblance to each > other, either. > > All this appears consistent with what amateurs are finding with practical > antenna systems at LF. > > 73, > John From andre.kesteloot at ieee.org Wed Feb 28 07:35:13 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:51 2003 Subject: [Lf] LF Book Addendum] Message-ID: <3A9CF081.777D75D6@ieee.org> g3ldo wrote: > An item has been added to the LF Book Addendum regarding a formula for > designing a loading coil for maximum Q. Interestingly, the results agree > roughly with the experimental work done by Bill Bowers, described in the LF > book. > Some readers noted that, on some browsers, the text was rather small and > difficult to read. I have modified all the pages of the site > (http://web.ukonline.co.uk/g3ldo) to a larger fort size. I will try to do > something about a couple of the diagrams. > > Regards, > Peter, G3LDO > > From andre.kesteloot at ieee.org Wed Feb 28 07:36:48 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:51 2003 Subject: [Lf] LF: Antenna simulation programs] Message-ID: <3A9CF0DF.CA907B36@ieee.org> Dick Rollema wrote: > To All from PA0SE Interesting material (simulation programs) for > antenna freaks can be found at http://www.qsl.net./wb6tpu/swindex.html > . It is called the "Unofficial NEC Archive". 73, Dick, PA0SE -------------- next part -------------- An HTML attachment was scrubbed... URL: http://atanasoff.rf.org/pipermail/lf/attachments/20010228/6529ea0c/attachment.html From andre.kesteloot at ieee.org Wed Feb 28 07:42:02 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:51 2003 Subject: [Lf] Modifications Message-ID: <3A9CF21A.97B2A257@ieee.org> The following web site has modifications information on most ham gear http://www.mods.dk/index.htm Andre' N4ICK From W3HXF at aol.com Thu Mar 1 11:44:03 2001 From: W3HXF at aol.com (W3HXF@aol.com) Date: Thu Jul 3 13:43:51 2003 Subject: [Lf] Antenna loss resistance & impedance vs soil Message-ID: <17.124498af.27cfd653@aol.com> Has anyone seen any list of the relative losses in: > sand > sandy lome > good soil > rockey soil > rock > over mineral mines (in Idaho) > water saturated ground (underground stream) > water (fresh) > water (salt) > Does their relative standing change with large changes in frequency ( LF to HF to UHF)? 73, Bill W3HXF > Re- antenna loss resistance: A basic difficulty with direct impedance measurement of an LF antenna is that the loss resistance is much smaller than the magnitude of the reactance. > For example, an antenna with R(loss) = 50ohm, C = 500pF, has a capacitive reactance of 2.3405kohm. The magnitude of the combined impedance is 2.341kohm, and the phase angle 88.8degrees, so quite close to that of the pure capacitance. A bridge will produce an accurate measurement of the capacitance component, but much larger errors will occur in measuring the resistive component, which is only a few percent of the total impedance. Even a very good bridge will struggle to get anything more than a rough figure for the resistance. > > A better way to measure loss resistance is to cancel out the capacitive reactance of the antenna with a series loading coil (ie. tune it to resonance), and then measure the remaining resistance, as done by PA0SE. > > A seperate measurement is then required to determine the loss resistance of the loading coil. This can be done by resonating the loading coil with a low-loss capacitor in place of the antenna, and measuring the resistance again. From andre.kesteloot at ieee.org Mon Mar 5 07:27:47 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:52 2003 Subject: [Lf] [Fwd: LF: Re: 136kHz transmissions] Message-ID: <3AA38642.CD77D4E6@ieee.org> g3ldo wrote: > Larry said > > I have been having a bit of a problem receiving LF signals with ARGO, I am > > not able to see the signals due to interference. I have been looking for > > G3LDO with 60 seconds dits and nil just more and more interference. > > One of the reasons that have probably made it difficult to receive my > transmissions is that I haven't been transmitting. I put out an e-mail > message on the 18th Feb that I would be transmitting on the morning of the > 19th and although I did transmit there was no response of any sort. > > The cost of power over here in the UK is not cheap, and to run a transmitter > through the night takes around 6 to 8kW/hrs. Now, while the government has > granted us pensioners an extra ?200 for heating costs for the winter months, > we still have to be careful if we are not to run up large energy bills. > > I am quite happy to make transmissions over limited periods of time, where > they have the chance of being more effective. > If there is interest I will transmit this week (Monday to Friday) from 0530 > to 0630 on 135.920 using a dot period that allows the call to be sent within > the hour. > > Anyone interested? > > Regards, > Peter, G3LDO > > From andre.kesteloot at ieee.org Mon Mar 5 07:33:26 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:52 2003 Subject: [Lf] QSB on LF Message-ID: <3AA38796.EC334EEB@ieee.org> Rik Strobbe wrote: > Have heard OK1DTN for the last 2 weeks several times with good signals, > from 559 up to 589. But so far I always called him in vain. > Most of the time he has a fair amount of QSB on his signal (compared to > others at the same distance). > I wouldn't be surprised if he was running a long wire antenna, I getting > the impression that stations with relatively long wire antennas have more > QSB than those with small toploads or pure verticals. > Could it be that long wires radiate at steeper angles and thus produce more > skywave ? > > 73, Rik ON7YD > > At 10:41 5/03/01 +0100, you wrote: > >To All from PA0SE > > > >I worked OK1BTN on 25 February; sent 569, received 229. Heard G3YXM and > >ON6ND working him as well. > > > >73, Dick, PA0SE From andre.kesteloot at ieee.org Mon Mar 5 16:31:22 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:52 2003 Subject: [Lf] QSB on LF] Message-ID: <3AA405AA.8935864A@ieee.org> Mitch Powell wrote: > Andre: Just to add to the confusion (?) let me add the followiing, > based on extensive daily monitoring of AMRAD WA2XTF/12 at Front Royal > Virginia, a distance of 324 mi ( 520 kM). The WA2XTF signal appears > with great rugularity before local sunrise and is solid copy with no > QSB noticed through the observation period. At present ( 1545 EST) > (2045Z) the signal is audible and solid trace at the same time using > ARGO and Spectrogram. QSB has not been a problem, and the signal is a > steady and solid reference as I experiment throughout the winter with > different antenna configurations / preamps. > I believe you use a 1500 foot ( ~500m ) longwire - so I can certainly > guarantee I will receive your signal over a 12 hour period, well past > sunset. Later ( 2100 EST) 02Z ) the signal is very weak and disappears > normally until re-appearing with the sun ! > For your information. > > 73 > Mitch VE3OT > > ---------- > >From: "Andre' Kesteloot" > >To: lf-amrad , Mitch Powell VE3OT > > >Subject: QSB on LF > >Date: Mon, Mar 5, 2001, 0:33pm > > > > > > > > > Rik Strobbe wrote: > > > >> Have heard OK1DTN for the last 2 weeks several times with good signals, > >> from 559 up to 589. But so far I always called him in vain. > >> Most of the time he has a fair amount of QSB on his signal (compared to > >> others at the same distance). > >> I wouldn't be surprised if he was running a long wire antenna, I getting > >> the impression that stations with relatively long wire antennas have more > >> QSB than those with small toploads or pure verticals. > >> Could it be that long wires radiate at steeper angles and thus produce more > >> skywave ? > >> > >> 73, Rik ON7YD > >> > >> At 10:41 5/03/01 +0100, you wrote: > >> >To All from PA0SE > >> > > >> >I worked OK1BTN on 25 February; sent 569, received 229. Heard G3YXM and > >> >ON6ND working him as well. > >> > > >> >73, Dick, PA0SE > > > > From PowellM at claven.fanshawec.on.ca Tue Mar 6 11:13:02 2001 From: PowellM at claven.fanshawec.on.ca (Mitch Powell) Date: Thu Jul 3 13:43:52 2003 Subject: [Lf] 90 second dots Message-ID: <200103061722.f26HMVu22620@atanasoff.rf.org> Good morning: 90 second dots are Q5 here in London. At 11 pm EST audible on speaker - even with S6 noise floor here this morning. On spectrogram I can reduce audio level until all noise gone and XTF/12 is only trace on monitor. Very solid signal. Using 6 ft diameter (15 turn ) KI0LE type loop, with varactor tuned preamp. Suspended from tree branch at 5 meters height. Mitch VE3OT From andre.kesteloot at ieee.org Tue Mar 6 15:32:06 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:53 2003 Subject: [Lf] LF: Transatlantic modes - what next?] Message-ID: <3AA54946.34706D77@ieee.org> James Moritz wrote: > Dear LF Group, > > The winter has seen a fair amount of success in the transatlantic > tests, and now that the "season" is probably near to an end, it is > worth thinking about what the next steps could be, in good time for > next winter. The following ramblings were the result of thinking what > I could do next, in the way of technical development of my LF > station, in particular regarding what would be the best mode to > work on: > ------------------------------------------------------------------------------------- > So far, all reported trans-atlantic signals have used some type of > QRSS. The variable parameter is the dot length - longer dots mean > better signal-to-noise ratio, with the penalty of slower message > transmission. Recognisable callsigns have been produced with 60s > dots or longer, which requires more than an hour to transmit one > callsign. ON7YD's DFCW roughly halves the time required, at the > expense of doubling the bandwidth occupied by the transmitted > signal and being slightly more complex to implement, which seems > to be a good trade-off. > > The maximum radiated power available to several stations has > reached the 1W ERP level in Europe, and somewhat more than > this for the stations active in Canada. The ERP that is feasible > depends mostly on how big an antenna can be put up, but in any > case is limited by regulation to 1W in Europe, which eliminates > further improvements. ERPs of a few 100 milliwatts have been > sufficient to cross the Atlantic on several occasions. > > Under optimum conditions, with favorably sited and equipped > stations, 3s per dot QRSS signals have been passed both ways > across the Atlantic, but this is the exception rather than the rule. > The problem with longer duration dots is that any kind of 2-way > contact takes an excessively long time, running into several hours. > This problem is compounded by the fact that propagation "lifts" on > LF only last an hour or so. So it would seem we are reaching the > practical limits with QRSS. > > What is required for a practical 2 way LF DX mode, capable of > operating at the extremes of distance and SNR? A while ago, > G4JNT posted an estimate of what might be theoretically possible > using different techniques; another way is to look at what is > needed to serve our purposes. I would suggest the following "wish > list": > > 1)Be able to complete a minimal QSO (about 50 characters) in one > hour. This would give the lowest rate of signalling capable of using > the propagation lifts to complete a QSO "in one sitting". > > 2)Be able to transmit/receive all alphanumeric characters and > essential punctuation/procedure signs, in order to be generally > usable by any station without special arrangements. > > 3)Occupy a bandwidth of less than 10Hz - this is neccesary > because of the very limited spectrum available, and the fact that > several stations will be operating simultaneously. > > The QRSS modes easily meet 2 and 3; in order to meet 1, a dot > length of about 7 seconds maximum would be required. With the > best possible conditions, I guess several stations might manage > transatlantic QSOs with these dot lengths. However, it would > probably not be enough to reach the more inland parts of Canada, > or the USA and further afield. By the way, I reckon about 6dB SNR > is needed to see a QRSS signal on a spectrogram under > favourable conditions; if there is much QRN, 10dB is probably > required. It is possible to see a trace of signal with 0dB or less > SNR. All this is fairly subjective, however. > > One way to use longer dot lengths without increasing overall QSO > time is to use multiple frequencies - for example, DFCW, VA3LK's > 7-tone scheme, and VK2ZTO's one-tone-per character VFSKCW. > Taking this to it's logical extreme, it would be possible to assign > different frequencies to all possible combinations of callsigns and > signal reports, so each over of a QSO would just consist of a > single tone. However, it would then be difficult to meet condition 2. > I guess there must be an optimum trade off between number of > tones, difficulty of encoding and decoding, redundancy and so on. I > suspect it might be 2 tone DFCW, but I don't know. > > Then there are the "digital" modes, specifically BPSK. Currently, > most effort has been expended on the MS100, 10 bits per second > variety of BPSK. This easily meets conditions 1 and 2. However, > for the same signal levels, QRSS seems to do better with > acceptable, if much slower, speed. Also, the bandwidth occupied is > roughly 40Hz, too wide for condition 3. But with the 16 bits per > character coding scheme normally used for BPSK, 2250 > characters per hour can be transmitted, far higher than is actually > required. So the bit rate could be greatly reduced, and/or the > coding altered to a greatly increased number of bits per character, > hopefully improving the readability of the signal. Reducing the > overall speed by a factor as much as 45 would still meet condition > 1. To fit into a 10Hz bandwidth, the bit rate would have to be 2.5 > bits/sec (MS400) or less, so you could encode each character with > up to 180 bits if you wanted to. Or, sticking with 16 bit codes, 0.22 > bits/second (MS4500) would still be OK. What we want is the best > trade off between bit rate and encoding for very poor signal to > noise ratio. I don't know a great deal about this subject, but I > expect some readers of this reflector already know the answer. > > Beacon signals are a bit different; here, the only requirement is to > positively identify the signal, and make some estimate of the signal > level. An on-off keyed carrier with a simple repeating pattern and a > well defined frequency is easily identified with simple equipment, > and has the advantage of flexibility at the receiving end - you can > make the bandwidth arbitrarily narrow, or perhaps take advantage > of the coherent nature of the signal, to improve detection > capability. You can also monitor several signals at once. > > So any suggestions/comments would be welcome - well, almost > any! By the way, I now have BPSK at up to 1200W PEP from my > Decca TX, if anyone would like a sked/tests, etc. > > Cheers, Jim Moritz > 73 de M0BMU From andre.kesteloot at ieee.org Tue Mar 6 15:40:35 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:53 2003 Subject: [Lf] WOLF Mode Records! Message-ID: <3AA54B43.2188338E@ieee.org> Les Rayburn wrote: > On this side of the Atlantic, US Lowfers are experimenting with a new weak > signal mode > called "WOLF" developed by Stewart Nelson, KK7KA. It has proven to be far > superior > to QRSS(S) mode in both off air and on-air tests to date. > > Lyle Koehler, K0LR conducted off air tests where he mixed a random sample > of LF noise > with the desired signals from a variety of modes. The results were: > > CW (by ear) -18db below the noise > QRSS (3 sec dots) -27db below the noise > QRSS(S) (60 sec dots) -31db below the noise > WOLF -40db below the noise > > These tests have been further confirmed by on-air tests as well. Despite > the Springtime > QRN, record breaking receptions in WOLF mode have been made in the past few > days including Stewart's reception of the XM(GR) beacon at a distance of > 1,874 miles > with a 1 watt input (2 milliwatt ERP) beacon. > > I urge LF'ers on both sides of the pond to investigate this exciting new > mode. It offers > the promise of Trans-Atlantic QSO's even with current US power limits...and > certainly > with the type of ERP common in Europe and Canada. > > Please note that not only is the weak signal performance of this mode > superior to QRSS > but also that more information can be passed in a given time frame. > Currently, WOLF uses > a 15 byte message format that can be totally unknown to the receiving > station (AS WAS > THE CASE IN ALL TEST TRANSMISSIONS SO FAR) resulting in little doubt that > an actual reception or QSO has occurred. > > More info can be found on the Noise Floor Web site: > > http://www.highnoonfilm.com/xmgr/updates/wolf.htm > > 73, > > Les Rayburn, N1LF > 4919 Cox Cove > Helena, AL 35080 > XMGR 184.900khz > 1LF 187.300khz From andre.kesteloot at ieee.org Wed Mar 7 09:08:42 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:53 2003 Subject: [Lf] Intercontinental modes - what next?] Message-ID: <3AA640E9.D8441D99@ieee.org> Larry Kayser wrote: > Jim and the others who have commented - Wonderful, a great start to a > discussion that is needed at this time of year. > > I offer that there are two, as I see it, distinct directions we are moving > to, the first is the use of DFT processes for detecting power in smaller and > smaller buckets (read as longer and longer information bits) and secondly > those who are into using information coding to decrease the time for the > transfer of information at the expense of needing a higher level of signal. > The later is what I consider to be the more tranditional mode of amateur > radio operating. > > Jim's three step "wish list" is an excellent documentation of the second > mode, a more traditional orientation, of item two above. I wish those who > wish to focus on what I call the second mode well, and good luck going down > that road - I however will not be with you in that area of focus for next > year. > > For the rest of the 2001 spring season I am available to run long duration > 90 second per bit QSO attempts or to have a special session of transmitting > WOLF data if there is any interest in Europe in having such a test session. > > WOLF is extremely difficult for me to send, the I/O implementation choosen > by Stewart when mixed with my situation here makes if very difficult - but > if there is interest I am available to run a couple of overnight tests > before the end of this season. I have loaded 18 hours of WOLF in one file, > in 25 minute segments, thank goodness for 30 gigabyte hard drives! I will > have to build up some hardware and do a fair amount of software to make WOLF > work from here - if the interest is present I will do it. The operative > words here are to set a time period and a reasonable level of participation > from Europe. > > My work going forward from here will focus on extream weak signal detection > which continues with the goals I set here when I came to the LF community > some 18 months ago. My focus will now shift to Time and Frequency coherency > to not worse than a part or two in 10-11th. I now have GPS controlled > systems at both my home and the remote site, they are not yet complete but > they exist and will be completly functional by the fall. > > The status of LF operation from Canada remains tenuous. The TransAtlantic > II project that was the basis of Canadian participation on LF has been > eclipsed from bordering on believability and achievability a year ago to > common practice in so short a time as to place in question much of the > "common wisdom" of the day. A plan for an LF allocation in Canada is before > our regulatory authority, the issue is - will enough time and resources be > available to do the work of authorizing general use of the LF band be > available in the near future? > > The next issue is how many amateurs will build the systems and learn the > tricks to have an active LF community - there will be at least a year of > growth needed. With just three transmitting stations in Canada now we have > seen the limits of LF paticipation, aural only operation only by Jack, > VE1ZZ, and severly hampered (foliage challenged) LF operation by Mitch, > VE3OT and my own setup here in eastern Ontario. The situation of an LF > allocation in the United States is certainly not understood by myself - but > it can be said there is a community waiting for the opportunity to make use > of an LF allocation, but at the moment there is no certainty of > participation and this community will need growth time as well. > > This being said, there is also some opportunity in the information coding > area. WOLF uses an internal synchronization process, very costly in > information bits. There are opportunities in Time Coherency as well as the > Turbo Product Codes that are achieving very high levels of performance > approaching the Shannon limit. (By the way Dr. Shannon passed away only a > month ago I learned in yesterday's newspaper). I personally want very much > to understand these coding processes and demodulation/modulation methods > enough to write my own code and experiment with them on the air, this is the > only way I will return to the information coding area of operation that I > mentioned above. > > The current operational status from here is that I continue to see many > trace level weak signals from Europe almost every night. Many of them are > using bit rates that result is complete smearing here and are not readable > at all. > > I have tested the 7 level FSK coding on 160M and as well on 20 Meters > (hiding in amongst the DX Beacons on 14100 kHz - they are spread out over > about 150 Hz - terrible waste of spectrum Hi). I do not recommend this work > go further, there is far greater value in the information coding mentioned > above and it is important to focus our efforts in order to make meaningful > progress. > > I have no idea why but I have still not seen a single recognizable DFCW > signal on this side of the Atlantic. > > The two different directions that I mentioned at the start of this memo, DFT > with longer and longer bits, and the use of information coding to increase > the signalling rate are I suggest critical to the evolution of LF. I ask > each of you to consider and comment on this segmentation and what you see as > your participation in the "speaking slowly" mode of operation. I am keen to > find others to work with in this area of extremely weak signal > communications. I encourage others who might wish to focus on really really > weak signal work to contact me directly. > > Larry > VA3LK From andre.kesteloot at ieee.org Sun Mar 11 10:45:13 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:53 2003 Subject: [Lf] Enigma in the US Message-ID: <3AAB9D88.EA23B0CB@ieee.org> The following interesting texts were forwarded to me by Richard O'Neill: Andre' N4ICK Anyone interested in the Enigma saga and the personal sacrifices made is encouraged to read the story at the bottom of this page; < http://www.activedayton.com/partners/ddn/ From riese-k3djc at juno.com Mon Mar 12 20:40:26 2001 From: riese-k3djc at juno.com (BOB RIESE) Date: Thu Jul 3 13:43:54 2003 Subject: [Lf] WOW Message-ID: <20010312.211444.-765427.1.riese-k3djc@juno.com> In the 1960's I had an active aerial using an 807 as the front-end - with 600v on it too! Later modified to use an E186F instead. Why are they using double triode E88CC? Can't possibly have the slope and overload characteristics of an E186F. Walter G3JKV. OK Frank here is something to strive for when the Active antenna ////////// becomes : 0 ) Bob K3DJC From fgentges at mindspring.com Mon Mar 12 22:00:57 2001 From: fgentges at mindspring.com (Frank Gentges =?iso-8859-1?Q?K=D8BRA?=) Date: Thu Jul 3 13:43:54 2003 Subject: [Lf] WOW In-Reply-To: <20010312.211444.-765427.1.riese-k3djc@juno.com> Message-ID: <5.0.2.1.0.20010312215903.02e58570@pop.mindspring.com> Bob, Maybe a 4-1000 with 6 kv on it would do even better. Frank At 08:40 PM 3/12/01 -0500, BOB RIESE wrote: >In the 1960's I had an active aerial using an 807 as the front-end - with > >600v on it too! >Later modified to use an E186F instead. Why are they using double triode >E88CC? >Can't possibly have the slope and overload characteristics of an E186F. > >Walter G3JKV. > >OK Frank here is something to strive for >when the Active antenna ////////// becomes > >: 0 ) > >Bob K3DJC >_______________________________________________ >lf mailing list >lf@amrad.org >http://www.amrad.org/mailman/listinfo/lf Frank Gentges K?BRA fgentges@mindspring.com From andre.kesteloot at ieee.org Thu Mar 15 17:42:39 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:54 2003 Subject: [Lf] Transatlantic Challenge: the Canadian / Europe contacts] Message-ID: <3AB1455E.9EFAACAF@ieee.org> John W Gould wrote: > The three sponsors of the Transatlantic Challenge have considered the two > recent transatlantic contacts. We were impressed by the dedication, skill > and perseverance that was shown in each case. The contacts were so > incredible that we had not anticipate the ways in which they were achieved > when we devised the rules! > > In these unexpected circumstances, and taking into consideration the intent > behind setting up the Challenge that was to commemorate Peter Bobek's > practical and fun approach to amateur radio, we have unanimously decided to > award both contacts with special plaques to commemorate their achievements, > that is the contact between VA3LK, G3AQC, and the contact between VE1ZZ, > VE1ZJ and G3LDO. > > In these circumstances we will not make a further award for a Canadian and > European QSO. Further, we have clarified the rules for the case of the > outstanding USA to Europe QSO (once and if the FAA agree to licence the band > for amateur usage in the USA). > > I hope that all involved in this LF aspect of our hobby will accept this > outcome and continue the excellent work that is being done to improve and > innovate reception, transmission, and aerial technology. > > On behalf of my colleagues and their committees our appreciation goes out to > the work of those who we will be awarding plaques. But we would also like > to extend our appreciation to the work carried out by many others who have > made experimentation on this amateur allocation such an interesting and > absorbing hobby. > > Best 73 > > John Gould > G3WKL > RSGB HF Committee > > On behalf of DARC, AMRAD and RSGB From andre.kesteloot at ieee.org Wed Mar 21 23:02:04 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:55 2003 Subject: [Lf] [Fwd: LF: Wolf BPSK across pond] Message-ID: <3AB9793B.6AC59B41@ieee.org> James Moritz wrote: > Dear LF Group, > > I arrived at work this morning to find that: > > > Well, WOLF has successfully crossed the pond. Got two lines of clean > > copy between 0135 and 0200 Z tonight (3/19 Z). Frequency was about 0.13 > > Hz below 137.5 kHz. Had to do some tweaking to get the copy. Those > > command line switches do come in handy. > > > > John Andrews, W1TAG > > > > Many thanks to John for this report, and his perseverance. Also to Stewart, KK7KA for developing the mode in the first place. I believe this is the first time a mode other than QRSS or DFCW has benn successfully copied across the pond. > > I will run some more tests this evening; details to follow. > > Cheers, Jim Moritz > 73 de M0BMU -------------- next part -------------- An embedded message was scrubbed... From: "James Moritz" Subject: LF: Wolf BPSK across pond Date: Mon, 19 Mar 2001 13:06:39 +0000 Size: 2549 Url: http://atanasoff.rf.org/pipermail/lf/attachments/20010321/16498861/attachment.txt From andre.kesteloot at ieee.org Wed Mar 21 23:03:35 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:55 2003 Subject: [Lf] [Fwd: LF: lf transatlantic] Message-ID: <3AB97996.AF459952@ieee.org> John Currie wrote: > Hi all , Just some thoughts. I only have anecdotal evidence for what I > am about to write but anyway here are some feelings. Since we went to > 30 second dots I cant remember a night when I didn't see a UK station > here except when either > 1. Nobody was transmitting or > 2 I had severe 60 HZ pickup > In other words the path between US es Nova Scotia is > available to stations with erp of the order of Laurie's 0.3 watt or > better most of the time. I have seen M0BMU or G3AQC when 129.9 or > DCF39 were as weak as S-4. Normally the 2 german stations are S-5 to > S-7 . Last night at around 0400 128.9 was S-8 but G3AQC was weaker > than usual. On at least one occaision M0BMU was received well even > though the K index was a 3. > I feel the path is therefore quite reliable and QRSS with 30 > second dots will produce QSOs more than half the winter nights. Some > nights such as when I visited Jack'S house condx can be bad and even > Jack's signals are not reliable. But even that night we saw MM0ALM for > 1/2 hour and I believe Jack would have been at least "M" copy if he > were using 30 second dots rather than 3 sec dots. > QRN doesn't seem to have much effect. I have seen EU stns > through static crashes during snow storms that were 10 db over S-9 on > peaks. During precipitation static caused by charged snowflakes all > sigs were wiped out. > My belief is that we will be able to get through even during > most of the summer. i would like to continue testing throughout > summer. I do not think we need to have continuous beaconing. Perhaps > 20 minutes at top of hour from Eu and 20 min at bottom of hour from NA . > > My sunset now is around 2200Z so I don't start seeing Eu > stations til 2130Z So no point in starting before 2130Z. My sunset at > summer solstice will be around 2345z So starting time then of 2315Z > would be good . Is anybody interested in continuing through summer? > Last night had 60 Hz trouble only saw G3AQC > 73 all de John VE1ZJ From andre.kesteloot at ieee.org Wed Mar 21 23:07:00 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:55 2003 Subject: [Lf] [Fwd: LF: The EF50] Message-ID: <3AB97A63.356D1BC7@ieee.org> Walter Blanchard wrote: > Although off-subject there seems to be a lot of interest in the EF50. > Attached is a text-only version of a recent article written by > Keith Thrower, an ex-Director of Racal and an electronics historian. > It comes from the journal of the "Centre for the History of Defence > Electronics" > at Bournemouth University - http://chide.bournemouth.a.c.uk > > Walter G3JKV. > > > ------------------------------------------------------------------------ > The following article was published in the December 2000 issue of "Transmission Lines", the > journal of the "Centre for the History of Defence Electronics", based at Bournemouth > University. > > Illustrations have been omitted in this text-only copy to save space. > If you'd like to see the full article ask CHiDE for a copy of their journal - > chide@bournemouth.ac.uk. > > The Famous EF50 Valve of WWII > > by Keith Thrower OBE > > By the early 1930s screen grid and pentode valves were available for RF amplification for > frequencies up to about 30MHz, which was adequate for both broadcast and commercial > purposes at the time, when radio usage had not extended into the UHF band. At frequencies > above 30MHz the gain available from valves fell very sharply; there were two principal > problems: the first was caused by the inductance and capacitance of the internal leads that > connected the valve electrodes to the terminating pins; the second was due to the finite transit > time that the electrons took to travel between the valve electrodes. > > The first problem arose through the valve design and manufacturing techniques which had > evolved from those used in the electric lamp industry. One particular constructional feature of > the valve, copied directly from the lamp industry, was the use of an internal glass stem and > pinch that held the support wires to the electrode assembly, and also provided a vacuum seal > for the lead-out wires. The problem that arose from this method of construction was that the > total length of the connections from the electrodes to their terminating pins was quite long, > resulting in significant self-inductance of the wires as well as excessive self-capacitance > between them. At frequencies below 30MHz, these parasitic inductive and capacitive > components did not seriously affect the performance of the valve, but their effects became > increasingly more serious at frequencies above this. > > The second problem - the finite transit time for the electrons to move between the electrodes - > was very serious for valve circuits operating at frequencies above 30MHz. For a typical RF > valve of conventional construction, the transit time for the electrons to move between the > cathode and control grid was about one nanosecond (one thousand-millionth of a second). At > frequencies of a few megahertz, this transit time was insignificant compared with the time for > one cycle of the signal frequency. At 100MHz, however, the time was about 10% of one cycle > and this was very significant. The phase lag caused by this time delay resulted in a low input > resistance at high frequencies, which significantly reduced the amplification available. > > A great deal of experimental research work was carried out at the RCA laboratories during the > early 1930s to investigate the behaviour of radio frequency amplifier valves, where it was > found that improved circuit performance could be achieved if the valve dimensions were > reduced. With a linear reduction, the mutual conductance and other valve parameters remained > almost unchanged, but the lead inductance, interelectrode capacitance and electron transit time > all fell in direct proportion to the reduction of dimensions. In fact, such a linear reduction was > not practical; however, the tiny 'Acorn' valves that resulted from this work were capable of > providing amplification at frequencies up to about 400MHz. > > The first of these valves to go into production was the type 955 triode which was introduced > in 1934. This was followed by the 954 pentode in 1935 and a variable-mu pentode, the type > 956, in 1936 (see Figure 1). They all had indirectly heated cathodes, operating at 6.3V, 0.l5A. > The diameter of the heater-cathode assembly was comparable with that of a common > household pin and the overall length was less than one half. The capacitance between the > control grid and anode for both the triode and pentode was about half that of conventional > valves, and all other internal capacitances were also significantly reduced. > > Before long, acorn valves, based on the RCA design, were introduced in Britain by Mazda, > Marconi-Osram and Mullard. Initially, all the British acorn valves had 4V heaters, but 6.3V > versions were introduced in 1940. > Figure 2 shows how the input resistance of a valve is affected by transit time, where a > comparison is made between an acorn pentode and an equivalent, conventional pentode. At > 30MHz, the conventional pentode (B) has an input resistance of 17k which falls to only 1.5k > at 100MHz. The equivalent figures for the acorn pentode (A) are 220k at 30MHz and 20k at > 100MHz. This fall of input resistance, which has a critical effect on the amplification that the > valve can provide is inversely proportional to the square of the frequency: if the frequency is > doubled, the resistance falls by a factor of four and a ten-fold increase in frequency results in a > hundred-fold decrease of input resistance. It is not difficult to see, therefore, that conventional > valves were unsuitable for operation in the UHF band, whereas the acorn or similar miniature > valves were better suited. > > British companies, such as MOV and Mullard, found the acorn valves very difficult to > manufacture because of the highly skilled labour required. As a result, considerable quantities > of the valves were imported from the US for use in military radar equipment during World > War 2. Because of the manufacturing problems and the eventual availability of alternative > valves, the acorn types were blacklisted by the Inter-Service Technical Valve Committee in > June 1941. > > With the commencement of high definition television in 1936 there was a need for a new type > of valve capable of providing wideband RF amplification. The frequencies required for the > Alexandra Palace transmission were 41.5MHz for the sound channel and 45MHz for the vision > channel, the latter requiring a bandwidth of 3MHz in order to accommodate the full picture > information. In order to achieve satisfactory amplification of the video signal, valves were > required with a high value of mutual conductance, and if this amplification was to be achieved > at RF the valves must have low values of internal capacitance and self-inductance, in addition > to a short electron transit time. The early valves produced for this role were far from > satisfactory. > > By the mid-1930s top-secret work was in progress at Bawdsey Manor in Essex on radio > direction finding (RDF)later to be re-named radar. For this, once again, valves capable of > providing wideband UHF amplification were required. At this time Tom Goldup, a senior > director of the Mullard Valve Company, was liaising with the British government and was > made aware of this requirement. Mullard was wholly owned by the Dutch Philips Company > and all the valve R&D work was carried out at the Philips Eindhoven plant. Goldup > approached Philips asking if there was a valve with the required specification. (Because RDF > could not be mentioned I suspect he referred to television applications.) He was told that a > suitable valve was being developed for the Dutch government; samples, therefore, could not > be supplied to Mullard. It would appear that the UK government approached the Dutch > government and samples were then supplied. The valve in question was the EF50, which > became available for television use in 1939. At this time all the valves were being > manufactured in Holland. > > The construction of the Mullard FF50 is of interest because it marked a significant departure > from the conventional types used in Britain at the time. The usual Bakelite base and internal > glass pinch were replaced by an all-glass base. Elimination of the stem and pinch resulted in a > considerable reduction in length of the internal wires. The valve had nine chromium-iron pins, > which were sealed into the glass base and arranged uniformly around a central metallic spigot, > which was keyed in order to facilitate insertion into the valveholder. The spigot was joined to > an external metal screen that covered the whole base, with small holes to allow the pins > through. Because of the screening provided, it was possible to bring all the connections out to > the base, avoiding the need for a top cap connection. > With the outbreak of war it was realized that the supply of EF50 valves would dry up and > Mullard did not have the capability of manufacturing the special glass base with sealed-in pins. > Consequently, just before Germany invaded Holland, a truck came from Holland with one > million of these glass bases. Later, huge numbers of the valves were manufactured by Sylvania > in the US. > > Figure 4 shows a selection of EF50 valves from various suppliers available during the War. > The original Air Force type number was VR91, the Army type ARP35 and the CV number > 1091. From left to right these are: > > (i) and (ii) Sylvania manufactured VR91, front and back view. > (iii) Silver UK version of VR91 for RAF use. > (iv) Silver UK version ARP35 for Army use. > (v) Mullard EF50 red. > (vi) Mullard EF50 silver > (vii) Cossor 63SPT > (viii) Osram Z90. > > A typical use of the EF5O was in the Pye 45MHz IF strip - Receiving Unit Type 153 - which > was used universally in British radar equipment during the war. A picture of this can be seen in > Figure 5. It had six EF50s (VR91s) and one EA50 (VR92) miniature signal diode. > > A variant of the EF50 was the RL7 (VR136). This had aligned grids to reduce partition noise, > and the cathode was connected by leads to two separate pins to reduce still further the > selfinductance. The valve was capable of proving RF amplification at 200MHz and could thus > displace the acorn valve. In post war years it was re-designated as EF54. > > Acknowledgements > > I am grateful to Dr Graham Winbolt who provided the photographs of the EF5O valves in > Figure 4 and the Receiving Unit Type 153 in Figure 5. The information on the RL7 was > obtained from Brian Callick's excellent book Metres to Microwaves (published by Peter > Peregrinus Ltd and obtainable from the IEE). > For more information on early British valves see History of the British Radio Valve to 1940 by > K Thrower and published by Speedwell. From andre.kesteloot at ieee.org Thu Mar 22 08:21:03 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:56 2003 Subject: [Lf] WOLF - Transmit? Message-ID: <3AB9FC3E.E1459309@ieee.org> Stewart Nelson wrote: > Hi Mike and all, > > Bill de Carle VE2IQ has added WOLF mode to his KEYER package. > Can upload to keyer or provide data for an EPROM, etc. > Download from Bill's web page at > http://cafe.rapidus.net/bill1/bbs.htm . > > 73, > > Stewart KK7KA > > ----- Original Message ----- > From: "Mike Dennison" > To: > Sent: Wednesday, March 21, 2001 4:30 AM > Subject: LF: WOLF - Transmit? > > > Ok, so having cracked the receive side, how do I transmit WOLF? > > > > As I understand it there are three methods: > > > > 1 - Audio from the soundcard is fed into a 136kHz SSB transmitter, including > > of course an HF SSB Tx with a transverter. Presumably the transmission is > > independent of which sideband is selected. > > > > 2 - Audio from the soundcard can be combined with the 'VFO' in an XOR gate > > and fed into an amplifier - presumably linear. This looks useful to me as I > have > > a 200W linear amp. > > > > 3 - The M0BMU method that allows the use of a non-linear Class D Tx. How > > and why does this work? > > > > All three methods are potentially simple, but are made complex by the need for > > very careful bandwidth tailoring to keep the transmission to about 20Hz wide. > > > > Have I got any of this wrong? Is there anything published on the subject? > > What is in use? > > > > I understand that some Lowfers have used WOLF, but I suspect that > > bandwidth has not been an issue because of the total width of the allocation > > and the low ERP. I believe that Larry, VA3LK, has transmitted WOLF, but > > again perhaps the bandwidth was not a problem. Jim, will you publish your > > circuits? Or perhaps they are rig specific? > > > > It appears relatively easy to get going on receive but practical transmit has > an > > information black hole. > > > > Advice, please. > > > > > > > > Mike, G3XDV (IO91VT) > > http://www.lf.thersgb.net > > > > From andre.kesteloot at ieee.org Thu Mar 22 17:02:22 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:56 2003 Subject: [Lf] BPSK Modulator details] Message-ID: <3ABA766D.173F40C4@ieee.org> James Moritz wrote: > Dear Mike, LF group, > > I am in the process of putting together some info about my BPSK modulator for the Decca class D PA - it will take a little time to collate all the details from my meticulously cross-referenced notebook (ahem..), but here is some general information about the method I am using. > > The BPSK signal can be generated by exclusive-ORing an AF or RF carrier with the binary keying data. this produces an output whose phase is unchanged when the data value is zero, but shifted by 180 degrees (ie. inverted) when the data is 1. This signal can be amplified by any linear or non-linear amplifier, and is a perfectly OK signal as far as demodulating goes, but it also generates sidebands analogous to key-clicks from a CW TX. In fact, for the same transmit PEP, the clicks generated by BPSK will be 6dB stronger than an on-off CW signal. So obviously, if you are trying to generate 1W ERP it isn't really on, although you can get away with it for a QRP transmitter. > > The remedy is similar to that used for CW: the output is gently reduced to zero before the phase change occurs, then gently increased to it's full value again after, in other words amplitude modulation is applied to the BPSK signal, as well as phase modulation. It turns out the ideal amplitude envelope is like a full- wave rectified sine wave - see the description of PSK31 in the LF handbook, which is basically the same. > > There are two main ways of generating this signal in practice - the most popular is to synthesise the waveform directly using a DSP algorithm and a digital to analogue converter, eg. soundcard plus software. However, most DSP DACs are limited to audio frequency outputs, so the signal must be mixed up to RF, and also amplified in a linear PA so the modulation envelope does not get distorted. However, If you have an HF rig with LF output, and a QRO linear PA, this is the easiest route to a BPSK capability. > > I didn't have, so... > > The other method is to apply the phase modulated signal direct to the PA, and simultaneously amplitude modulate the PA to get the required envelope. A class D PA is well suited to this due to the linear relation between supply voltage and RF output amplitude - what is required is to replace the normal DC supply with the full- wave rectified sine waveform which follows the phase transitions. > > The advantages of this are: > -Efficiency can be relatively high compared to a linear > -No frequency conversion means few spurious outputs, and minimal frequency errors. > -Simplified digital system required. > > In my present system, the 136kHz carrier is generated by a synthesiser, and phase keyed using a simple ex-or gate. The envelope modulating waveform is generated from the phase keying signal. The envelope-shaping part is built using 4000 series logic and some analogue bits. It is a prime candidate for implementation using a PIC with a D/A, but I haven't got a programmer, hence the hard wired circuit. It is synchronously clocked at 256 x the bit rate by a 555 timer. The incoming phase signal is appied to a transition detector. When a transition occurs, an 8-bit counter is reset, which clocks through all it's states and then stops. The 4 MSBs are used as the addresses for a 16 input analogue MUX. The MUX inputs are connected to taps on a sine weighted potential divider fed with a DC reference voltage, producing a stepped approximation to the modulation envelope, which is low pass filtered to smooth it out. This then goes to the power stage of the modulator. The "middle" count of the > counter is decoded and used to clock the phase data through a D flip-flop to get a delayed phase output, which is what is actually fed into the ex-or phase modulator, to keep it in step with the modulation envelope. The reference voltage can also be keyed through another LPF to get a nice textbook CW keying waveform. > > The high power modulator part is physically the biggest bit. > I started off wanting to build a PWM modulator, but it ended up > being linear - this sounds like a thoroughly bad idea, massive heatsinks and so on, but the power dissipation did not turn out as bad as you might think. It evolved like this: > > With a PWM, the output tends to be quite spiky due to non - ideal > filter components, and the amount of filtering you can apply is limited - very big filter capacitors limit the slew rate of the output in the troughs of the modulation, multi-section filters introduce other problems, especially if you want to use feedback to improve regulation, reduce mains ripple etc. The spikes will produce IM products in the PA output, which Murphy's law dictates will be at the right frequency to cause maximum trouble. One way round this would be to clock the PWM at the carrier frequency (or better, 2x), but then you end up with something quite big and complex due to the high frequency, with higher switching losses to boot, which defeats the object. > > So I looked again at using a linear circuit. If you keep the input- > output voltage differential to a minimum while transmitting a continuous carrier, the power dissipation is minimised. Since you don't really need a perfectly constant output provided it is reasonably ripple free and so on, the modulator output can be made to track variations of the input voltage, and maintain a roughly constant, small, differential. I did this by using a filtered sample of the raw input DC as the reference voltage for the envelope waveform circuit described above. > > When sending CW at full power, the output to the Decca PA is 60V max, 21.4A, and the differential 5V. Power dissipation is 107W. During the phase transitions of BPSK, power dissipation is higher, but in fact with a sinusoidal envelope, average dissipation works out to 243W for phase transitions on every bit, or 175W for a phase transition every two bits, which I reckon is about average. The power dissipated is therefore similar to a 300 - 400W linear, which is quite managable. I think the overall TX efficiency DC input - > TX out is near 75 - 80% still, so not too bad. With a PWM modulator, there would still be some dissipation and you would be lucky to get 90% overall efficiency, so overall there is not a huge difference between the two approaches - less than 1dB in signal terms. The pass element uses 8 x STW34NB20 Mosfets, which is a bit oversized, but was done in case I felt like increasing output in the future. 5 or 6 would do. The linear design makes it very easy to include > foldback current limiting and so on. Each MOSFET is driven by a seperate op-amp to ensure even current sharing, and individual current limiting for each device. Overall, the circuit maintains a fraction of the output voltage equal to the instantaneous amplitude of modulation waveform - in other words, it is a big feedback amplifier. This also serves the function of removing mains ripple from the PA supply > > The phase keying signal can be any logic level signal - for "Coherent", it uses the signal on one pin on the PC RS232 port provided for the purpose. For WOLF, I built a dedicated EPROM keyer, very similar to the Lowfer designs. This enables me to use the reference output of the synthesiser, divided down to 10Hz, to provide very accurate timing for the BPSK signal. The synthesiser uses a Racal 9442 OCXO reference, stable to within 1 part in 10^7, which it seems to manage easily. So you just dial in the frequency, and there is no messing around with frequency calibration for soundcards, HF rigs etc., thank goodness! > > The complete system is fully working with CW, QRSS and BPSK, but not yet finished. It is compatible with existing software for these modes. It should be flexible enough to use with other modulation methods, should these look promising. I think the results so far show that superior results can be acheived compared to a soundcard/SSB exciter/linear PA TX, althought there is obviously a lot more work involved. The same techniques could be applied to any class D TX. One thing I will do when I get the chance and the bits is to replace the current PSU with a variac/transformer/rectifier arrangement. I will get some legible circuit diagrams together when I get time; I am a bit pressed at the moment. > > Cheers, Jim Moritz > 73 de M0BMU From andre.kesteloot at ieee.org Fri Mar 23 17:36:28 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:56 2003 Subject: [Lf] QRS external timing Message-ID: <3ABBCFEB.BC769A6F@ieee.org> Rik Strobbe wrote: > Hello group, > > Recently there have been some requests to be able to let an external (and > accurate) timing source control the PC clock while running QRS. > I had a look at it and a basic 'external time control' was rather easy to > implement. > In version 3.06 beta 1 it is possible to connect a accurate timing source > to COM port CTS pin (on a D9 connector : pin 8, on a D25 : pin 5). At this > moment it must be a 1 minute clock source (maybe more posibilies later). > > You can download this version from : > http://www.qsl.net/on7yd/QRS/qrs306b1.zip > > In SETUP you can click on TIME to get to the external clock menue. There > you have 3 possibilies : > - DISABLE : no external clocking > - ABSOLUTE : the PC clock will increment 1 minute for every pulse at CTS > (compared to time at the previous pulse). > - ADJUSTING : a pulse at CTS will adjust the PC clock to the closest minute > > May sound complicated, therefore an example : > > 1. Before starting QRS you have to set the PC clock as accurate as you can > (by hand using the default windows device for setting the clock or using > software that sets the PC clock based on DCF77 or similar). > > 2A. If you select ABSOLUTE then QRS will take a 'reference time' at the > first pulse on CTS and from then on will increase time by 1 minute for > every pulse. In the time between the pulses the PC clock will run at its > own pace. > eg. Assume 14:25:36 is taken as reference time. At the next CTS pulse the > clock will be set to 14:26:36, then to 14:27:36 etc ... > > 2B. If you select ADJUSTING then QRS will also take a 'reference time' at > the first CTS pulse but from then on will only adjust the clock on every > CTS pulse. > eg. Assume 14:25:36 is taken as reference time. At the next CTS pulse QRS > reads the PC clock, let's say 14:26:35 -> this will be adjusted to 14:26:36. > > The difference between the 2 options is that if (for whatever reason) there > is a CTS pulse missed that in the ABSOLUTE mode the PC clock will be 1 > minute wrong while in the ADJUSTING mode the clock will be set correct as > long as the in the time between 2 CTS pulses it hasn't gone wrong more than > 30 seconds in its own pace. > > One could use an atomic clock or GPS to generate the 60 second timing, but > for the mere mortals a simple Xtal oscillator + divider train will do (keep > the error less than a second over a period of several days). > Keep in mind that the pulses must exactly come in a 60 second interval, but > that there is no need that the pulse comes just on a full minute. > Finaly : the pulse applied to CTS must be positive and have a width between > 10us and 10ms. > > If there is sufficient feedback I am willing to continue and make more > flexible external timing possibilies. > > 73, Rik ON7YD From fgentges at mindspring.com Sat Mar 24 22:08:09 2001 From: fgentges at mindspring.com (Frank Gentges =?iso-8859-1?Q?K=D8BRA?=) Date: Thu Jul 3 13:43:56 2003 Subject: [Lf] Grimeton Message-ID: <5.0.2.1.0.20010324220504.00a09590@pop.mindspring.com> I probably missed it and everyone has already seen it, but the radio Grimeton web page has been updated. It is worth a visit. See . Perhaps we can work up a cruise to include a visit. Frank Frank Gentges K?BRA fgentges@mindspring.com From andre.kesteloot at ieee.org Sun Mar 25 12:31:30 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:56 2003 Subject: [Lf] Technical info Message-ID: <3ABE2B71.D2FC5DE8@ieee.org> Gang, another web site of possible interest 73 Andre' N4ICK http://www.rason.org/Projects/projects.htm From andre.kesteloot at ieee.org Sun Mar 25 12:35:21 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:57 2003 Subject: [Lf] WJ357 Instruction manual ? Message-ID: <3ABE2C59.E4EFD998@ieee.org> Edward Ray wrote: > [...] > New Subject. My LF receiver is an old old Watkins Johnson 357, > which may have had it's manual(s) when I first acquired it, but they > are not anywhere that I can find in the several months of searching... > Would anybody on the AMRAD LF group know of a source for WJ357 > manuals. I have tried the new company, but they will not supply. > > Thanks & 73 Ed From andre.kesteloot at ieee.org Sun Mar 25 12:46:38 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:57 2003 Subject: [Lf] yet another site Message-ID: <3ABE2EFE.8272CB85@ieee.org> Yet another site of possible interest http://www.dvanhorn.org/Circuits/Index.php 73 Andre' N4ICK From andre.kesteloot at ieee.org Sun Mar 25 14:02:41 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:57 2003 Subject: [Lf] M0BMU "Wolfed" in the U.S.] Message-ID: <3ABE40D0.48728A4D@ieee.org> John Andrews wrote: > In my haste to get to bed last night, I neglected to post here that I > successfully copied M0BMU's WOLF transmission in a 25 minute recording made > from 0135 - 0200 UTC (19 Mar). There are two lines of clear copy at this > point. I say that, because I'm not done tweaking the various command line > parameters yet. As Jim has pointed out, you should enter the correct > sampling rate for your sound card, and this appears to be more important > with weak signals. Also, I find that adding short delays in increments of > 1/20 second (-s 400, -s 800...) may transform partial lines into complete > ones. > > I'm located in central Massachusetts, about 80 km west of Boston. This is a > fairly noisy residential area, and I'm stuck with a loud carrier just above > 137 kHz that does deafen my receiver somewhat. Hardly an ideal location. I > believe that my neighbor nearest the loop antenna turned their light dimmer > off around 0145 last night, thereby helping my situation greatly! > > John Andrews, W1TAG From andre.kesteloot at ieee.org Mon Mar 26 10:23:51 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:57 2003 Subject: [Lf] DOS/Windows and PC clocks] Message-ID: <3ABF5F07.C6E68DB@ieee.org> James Moritz wrote: > Dear LF Group, > > Although it may be possible to access the PC's internal clocks one > way or another, I can't see it would be much help for timing > accuracy - after all, it's all derrived from a very ordinary, un- > trimmed crystal on the motherboard somewhere. > > I did some work at U of H a while ago with Dave Lauder, G0SNO, > investigating PC clocks. In fact, a lot of PCs (and other things) are > now using 'dithered clocks', where the clock is frequency > modulated to a deviation of a fraction of a percent, by a spiky > looking triangle wave. The reason for doing this is to spread > radiated noise emissions from the PC over a wider range of > frequencies, which in turn reduces the noise power seen by a > narrow band EMC receiver when noise emissions testing is being > performed. This slightly perverse idea is basically a fiddle to allow > PC's to generate more RF noise, while still passing the EMC > regulations. It saves the manufacturers some money on screening > and filter components. I'm sure it does not do much for timing > accuracy, though! > > Cheers, Jim Moritz > 73 de M0BMU From andre.kesteloot at ieee.org Wed Mar 28 09:48:40 2001 From: andre.kesteloot at ieee.org (Andre' Kesteloot) Date: Thu Jul 3 13:43:57 2003 Subject: [Lf] [TECH] A question] Message-ID: <3AC1F9C8.7BCA01D2@ieee.org> Talbot Andrew wrote: > One method for determining S/N ration in an environment where signals > and noise are constantly changing - used a lot in Radar and Other > techniques - is an algorithm called Constant False Alarm Rate. I > covered this in detail in postings to this reflector several months ago, > but basically the technique is as follows : > > 1) Perform an FFT on a block of data > 2) Sort all the bins into increasing order of amplitude. > 3) Take the amplitude of the lower quartile bin. > 4) Add 3dB to this figure and this gives a very good approximation > to the noise level > 5) For new signal alarm and signal detection add a threshold - 10dB > is a good starting point > 6) Check for successive hits above this threshold N out of M times > before indicating valid. > > You will only be interested in satges 1) to 4). This assumes the real > noise level is flat across the FFT width, which I hope is true for all > narrowband work, but not necesssarily so for full SSB bandwidth > sampling. > > Andy G4JNT > > > -----Original Message----- > > From: Alberto di Bene [mailto:dibene@usa.net] > > Sent: 2001-03-27 13:33 > > To: rsgb_lf_group@blacksheep.org > > Subject: LF: [TECH] A question > > > > > > I have a question for you all. > > > > I am implementing both in Argo and Spectran a function that will > > display the relative level (in dB) of the spectral lines when > > you hover the > > mouse cursor over them. So far so good. > > What I am uncertain about, is that word, 'relative'. Relative > > to what ? > > > > One possibility is to first click on a given point of the > > display, take this > > bin amplitude as a reference, and the values subsequently > > displayed will > > be relative to this reference level. But frankly I don't > > like this solution > > very much, even if this will be perhaps the correct way to measure > > the S/N ratio, but this is another topic. > > > > Another solution which has been suggested is to take as reference > > level the saturation level of the ADC. This is quite valid is case of > > a single signal, but on a real case what will happen with this method > > is that the measured level will vary depending on the total > > input to the > > ADC, even if the signal being measured is constant in amplitude. > > > > I gave a thought about using the Parseval equation, but > > before pursuing > > this further, I decided to ask the question here, as perhaps > > this problem > > has been already encountered and solved by others. > > I am open to any suggestions and advices. Thanks. > > > > 73 Alberto I2PHD > > > > > > > > > > > > -- > The Information contained in this E-Mail and any subsequent correspondence > is private and is intended solely for the intended recipient(s). > For those other than the recipient any disclosure, copying, distribution, > or any action taken or omitted to be taken in reliance on such information is > prohibited and may be unlawful.