[Fwd: LF: Kite report]

Andre Kesteloot akestelo@bellatlantic.net
Sun, 05 Apr 1998 18:08:09 -0400

Peter Martinez wrote:

> >From Peter Martinez G3PLX Kendal Cumbria
> I have made good progress with the kite antenna system. After
> getting the kite aloft last weekend to measure it's capacitance, and
> a bit of beaconing at half-height, I built a variable tuning coil from two
> single-layer coils, wound on slightly different diameter glass jars,
> with the smaller one sliding inside the larger. Achieved 2.0-3.2mH,
> and have a 7 turn link to match 50 ohms. Also built a 50 ohm
> direction power meter, using two 50:1 toroidal transformers, one
> connected as a current sensor with a 50 ohm load, and the other as
> a voltage sensor, with the difference between the secondary voltages
> rectified and fed to a meter. It is flat from at least 50 kHz to at least
> 500kHz. These two items now make it possible to tune up the kite
> quickly.
> After waiting until Friday for the weather, I flew the kite at 300ft, but
> just as I got it tuned up on full power, the reverse power went
> full-scale, the receiver was dead, and the kite was nowhere to be
> seen. The neighbouring farmer found it the following day about half a
> mile downwind.
> While pondering stronger wire, I devised a mechanism on the kite for
> letting the wings fold against spring tension, and with a very light
> breeze on Sunday afternoon, managed to get the kite aloft, after
> taking it to the top of the hill to find some wind, letting it get some
> height then walking the end back down the hill to the house.
> Worked G3YXM, G3LDO, G4GVC, G3KEV, EI0CF, and G3XTZ, all
> reporting good signals. Those who had heard me on the 20ft high
> longwire reported about 3 S-points improvement. I was puzzled by
> the fact that I needed 3.2mH to tune it, and the kite didn't look very
> high, so I checked the wire length, to find it was only 75m, some
> 25m short of the original length. So my information in the QSO's
> that I had to the effect that the antenna was 300ft. were wrong. It
> was only 225ft. I noticed when I recovered the kite from downwind
> that the end of the wire had been chewed by a sheep. The missing
> wire is nowhere to be found so it rather looks as if that sheep has
> eaten 25m of pvc insulated wire! When I replace the missing wire I
> should be about 3dB stronger.
> 73
> Peter G3PLX