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Re: LF: TXing on VLF again, A fan in series to the antenna?! :-)

To: [email protected]org
Subject: Re: LF: TXing on VLF again, A fan in series to the antenna?! :-)
From: DK7FC <[email protected]>
Date: Thu, 14 Apr 2016 23:01:45 +0200
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Hi VLF,

Since 22:45 i'm running 200 mA on 8270.0050 Hz into my antenna again. 200 mA is the limitation of this compact yoghurt-coil. The overall system loss is about 1 kOhm, so i just need 40W to run the system at 100%. Or, in other words, power is not the limiting factor :-) There are holes into the single yoghurt cups so there can be an air flow in the cups. And this will be helpful/necessary in summer / daytime. 200 mA is about the current consumption of a 12V fan used in PC power supplies. So i've constructed a plate with a fan mounted on that, improvong the air flow. Later, a tube must be used to form a curve on the top of the arrangement to prevent water from flowing between the coils. Then, a forced air flow becomes necessary, normal thermal convection could be to small.
https://dl.dropboxusercontent.com/u/19882028/VLF/20160414_214939.jpg
https://dl.dropboxusercontent.com/u/19882028/VLF/20160414_215835.jpg
A normal bridge rectifier with UF4007 diodes, then 2 ZD15 Z-diodes, a single UF4007 diode (to reduce the voltage a bit) and a 100nF C, that's all. It works very well and automatically :-)
73, Stefan



Am 13.04.2016 23:28, schrieb Paul Nicholson:
Sorry Stefan, nothing showing for 20:14,+30m in
555uHz.   The noise floor there is 0.2 fT probably
due to all the thunderstorms in Europe tonight.
I expect your signal is down below 0.1 fT.

Also checked 20:14,+60m in 278 uHz in case you ran
for a full hour, but nothing.

Let's try again when the background is lower.

--
Paul Nicholson
--





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