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

To: [email protected]
Subject: Re: LF: TXing on VLF again, A fan in series to the antenna?! :-)
From: DK7FC <[email protected]>
Date: Fri, 15 Apr 2016 12:04:42 +0200
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Hi Paul,

Thanks for the peak :-)
When talking about ERP, how strong is Markus' and Uwes signal? Just to get an impression. I don't know their ERPs.

It was raining in the morning. I had to bring the coil down to the office again. In the coming days i want to build a waterproof construction, something like a small tent :-)

But the forced air flow by the fan is causing a swinging of the 2 small ferrite rods in the center of the coil. I can see it in the antenna current! So the phase is probably not very stable. I will search for a better solution and already know one, to be tested... Also i want to test the PLL with the small pickup probe tracking the local fields from the radiated signal.

Then i can run a 'key-down' carrier for one week or longer :-)

73, Stefan

Am 15.04.2016 10:27, schrieb Paul Nicholson:

This time, a good signal at about 0.35 fT

 http://abelian.org/vlf/tmp/160414a.gif

but the noise was high from the same direction so
cannot be avoided by steering the loops away.

I don't know if this is 150uW, from the signal
strength I might guess 50uW max, probably more
like 30uW.

I ran all 6300 seconds of the carrier through EbNaut to
decode an 'all-star' message at two settings:

 Code   Symbols    Chars   Eb/N0
 8K19A   15.0 sec    3     +0.5 dB
 16K25A   7.7 sec    3      0.0 dB

I couldn't get a 4 char message to decode.  If the
noise wasn't so high this signal would do very well.

How about a daytime test?

--
Paul Nicholson
--


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