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Re: ULF/VLF: amateur stair case / carrier transmissions

To: [email protected]
Subject: Re: ULF/VLF: amateur stair case / carrier transmissions
From: Roman <[email protected]>
Date: Wed, 26 Jun 2019 11:58:11 +0300
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Guten morgen Genosse Funkamateur Stefan!

Congrats with your success!

Let us to know more details about drone antenna?
We are discuss about that way in 2011 on forum.
Very interesting!


> Hi all,
> Today, some 20 minute long carrier transmissions were drone from JN39WI
> again. The main intention was to calibrate my local RDF spectrogram
> (still to be done) in the range below 16.4 kHz (JXN) and above 82 Hz
> (ZEVS). So that was a amateur radio ULF/VLF staircase somehow, despite
> the weak signal strength relative to commercial transmitters.
> It was a hot day! Far > 30 C here. I started early in the morning and
> enjoyed the fresh air in the forest.
> The DC resistance of the 1130m ground loop increased to 73.2 Ohm
> (measured at 1 A) due to the dry soil. It confirms the dependency shown
> in the last year! In 2018 i saw the resistance rising up to 94 Ohm in
> late October, then it dropped to 57 Ohm (-40 %) in just 2 months.
> It was interesting to see that the antenna current is much higher at
> lower frequencies (always at resonance | the PA output voltage is nearly
> constant). This effect was very clearly expressed.
> IF of interest for other stations (having a data storage):
> Frequency/Hz Start time/UTC Antenna current/A
> 970.005 2019-06-25_08:36:20,+20m 2.26
> 2970.005 2019-06-25_08:13:30,+20m 2.19
> 5170.005 2019-06-25_07:51:00,+20m 2.09
> 8270.005 2019-06-25_07:23:00,+25m 1.85
> end of the official part.
> BTW, since a few days, the VLF RX site at DL0AO has a 3 axis VLF
> receiver recording data from a Octo-soundcard and a Raspberry pi 3,
> saving data to a 4 TB HDD so there is one more station that won't miss
> anything from now on (for example unannounced transmissions by SAQ).
> Some spectrograms may be shown later.
> Evetually there was a problem with the sample rate correction due to the
> upheating car, which caused a high deviation of the tracked sample rate.
> The max allowed range of 10 ppm was left in the end of the experiment
> but this was noticed a bit late, maybe.
> 73, Stefan
Roman, RW3ADB

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