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From: DK1IS <DK1IS@kabelmail.de>
Message-ID: <c3e60fa8-eb49-a783-a81e-28b04e328ed3@kabelmail.de>
Date: Sat, 28 Jul 2018 17:18:45 +0200
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Subject: Re: VLF: Earth antenna transmissions on a guide rail?!?? NOW on the
 air...
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Hi Stefan,

congrats for that ufb earth antenna experience! You have certainly seen 
it already: from 9 to 10 UTC there was a clear trace from the east at 
Paul´s grabber: 
http://78.46.38.217/fbins3.html#p=1532782800&b=110&s=sp&m=cardioid&w=r&h=62&z1=0.34&z2=0.64&c=1 
- it should have been your signal! But sorry: at a first glance no 
signal at the DL0AO grabber but we have a lot of heavy QRN here today.

73 es gl,
Tom, DK1IS


Am 28.07.2018 um 11:43 schrieb DK7FC:
> Hi VLF,
>
> I'm sitting in my car while writing this email. I'm in JN39WI96GX and 
> i transmit on 8270.000 Hz with a GPS locked signal generator into an 
> about 450 m long earth antenna using two guide rails as the earth 
> electrodes on both ends. On each end there are 16 (18) massive T-T 
> poles holding the guide rail, providing a super good earth coupling. I 
> measured that they are connected to each other.
> The transmitter is on the air since 9:08 UTC running 550 mA with just 
> 75 W DC inout power into my hand warm lossy linear mode VLF PA!
>
> I'm amazed about the low losses! At DC i got 447 mA at 50.9 V. The 
> wire is 0.4 mm diameter so it has 63 Ohm. That means the ground loss 
> is just 50 Ohm !!!! Amazing! And i have no efforts to build up a 
> ground connection here, i just need to connect the wire. Since the 
> wire losses are higher than the ground losses, i can get maybe 2 dB 
> more signal when buying some better wire. I already found a source 
> that offers 0.75 mm^2 100 m loudspeaker cable (i.e. 200m wire)for just 
> 13 EUR....
>
> BTW i even have an ugly old scope here which is battery powered. I can 
> see that the phase of voltage and current is slightly inductive, maybe 
> 30 deg or so. So i could series resonate the antenna with some C. This 
> is for the next experiment...
>
> The signal becomes visible on my grabber now, in 424 uHz and also some 
> bright pixels in the 3.8 mHz window.
>
> I'm going to stop the carrier at 10:08 UTC, after 1 hour. Then i'll 
> continue on 5.17 kHz!
> BTW the antenna , if it works like a real loop, is beaming directly to 
> Paul Nicholson ;-)
>
> 73, Stefan