[Fwd: SV: SV: LF: Signals and voices (138.9 kHz)]
Mon, 31 Aug 1998 09:31:15 -0400
Johan Bodin wrote:
> Hi André and all,
> Andre Kesteloot wrote:
> > Note: it is interesting that the local gyrofrequency mentioned above is
> > close to that of the Sölvesborg Tx mentioned by Johan Bodin, SM6LKM
> Yes, it is very interesting. Thank's for the information. The message from
> Peter Martinez regarding Luxembourg Effect was also interesting to read,
> "the effect will be most pronounced when the modulating transmitter is in
> the 0.8-1.4 MHz region"
> When Radio Sweden turns off, about an hour after local midninght, I can
> still hear other voices on the 138.9 kHz carrier. I have not yet made any
> attempt to identify them. It will be interesting to find out where they are
> located with respect to the line between my QTH and the 138.9 kHz tx.
> If the D-layer is modulated by the AM, I guess the attenuation of the LF
> wave should be greatest on the modulation peaks on the AM signal.
> If this is the case, the "ghost" modulation would have a 180 degree
> phase relationship to the original AM audio. It would be interesting to
> measure the phase difference between them but propagation delay and
> bad SNR on the ghost audio will make it difficult, of course. A 100 Hz
> tone has a wavelength of 3000 km which is much more than the path
> length difference so perhaps it is possible to measure. The problem is
> to make the AM station transmit a steady low frequency tone...
> 73 de Johan Bodin, SM6LKM