Hello Wolf!
Good news: Today the GPS-module arrived.
I'm not sure how long it will take me to make it work but soon I will
transmit on a very stable QRG.
That should make it much easier for Paul and others to observe my
transmissions.
73 es tnx fer QSP
OE3GHB
Gerhard
Am Dienstag, den 25.01.2011, 17:38 +0100 schrieb wolf_dl4yhf:
> Hello Gerhard, Ossi, and group,
>
>
> This info just arrived here from the yahoo VLF group, not sure if it was
> already forwarded to the LF group. 73, Wolf DL4YHF .
>
> -----
>
> VLF transmit activity from Austria
> Date: Mon Jan 24, 2011 5:48 pm ((PST))
>
> OE3GHB's signal is a moving target! The frequency drifts
> quite a lot but yesterday (24th) for a couple of hours the
> drift was fairly linear and I could apply a suitable de-chirp.
>
> Integrating 12:00 to 14:00 in 138uHz resolution with a chirp
> rate of -1.05uHz/sec produces a peak of about 0.18fT crossing
> 8969.9676 Hz at 12:00,
>
> http://abelian.org/vlf/110124a.gif
>
> It's a pretty marginal sort of peak, but the frequency coincides
> with Gerhard's local spectrogram at 12:00 and is not present
> before the transmission.
>
> The required de-chirp was first estimated by counting pixels
> on Gerhard's spectrogram, then polished by running several
> spectra with a range of nearby values. Actually the chirp
> rate giving the highest peak was the original rate estimated.
>
> Without the de-chirp, his signal is spread across some
> 50 spectrum bins and is almost completely lost in the noise.
>
> There's a spurious signal here at 8969.95683 Hz, visible without
> the de-chirp,
>
> http://abelian.org/vlf/110124b.gif
>
> Gerhard's signal is just visible as the broad hump between -0.03
> and -0.04Hz. The bin amplitudes there are not individually
> significant against the prevailing noise, but 36 adjacent raised
> bins does indicate the presence of something and if the excess
> power was concentrated into a single bin the amplitude would
> be between 0.3 and 0.6fT. I guess the drift rate is just not
> linear enough to fully concentrate the signal.
>
> The range to JN88hl is 1422.5 km, so a little further than
> Ossi. I think Gerhard must be putting out quite a nice
> signal but it is lost because of the frequency drift.
> --
> Paul Nicholson
> --
>
>
>
>
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