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Date: Wed, 26 Jun 2019 11:57:44 +0200
From: DK7FC <selberdenken@posteo.de>
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References: <9ec649ed-7852-89b8-cb0e-d646de9538a9@rtv5.cz> <5D124169.1080309@posteo.de> <5D1268E1.9020500@posteo.de> <15144271561539491@myt5-cf6d29327892.qloud-c.yandex.net>
In-Reply-To: <15144271561539491@myt5-cf6d29327892.qloud-c.yandex.net>
Subject: Re: ULF/VLF: amateur stair case / carrier transmissions
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Hello Genosse Funkamateur Roman,

I'm sorry, the 'drone' was just a typo. I simply meant 'done' instead.

73,Stefan

Am 26.06.2019 10:58, schrieb Roman:
> 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 136.su forum.
> Very interesting!
>
> 73!
> Roman
>
>    
>> 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
>>