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Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests: 6.47kHz

To: [email protected]
Subject: Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests: 6.47kHz
From: Paul Nicholson <[email protected]>
Date: Tue, 15 Nov 2016 07:18:37 +0000
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Message 'DK7FC JN49IK 73' from Oct 7th
16K25A with 80 second symbols,
Eb/N0 = +1.1dB  BER 37.4%.

Carrier (after phase modulation reversed) in 6uHz bandwidth

 http://abelian.org/vlf/tmp/161115a.gif

Amplitude corresponds to 1.5 electron charges on the
E-field antenna.

The reconstructed carrier doesn't even show up in a
spectrogram in the bandwidth of the 80 second symbols

 http://abelian.org/vlf/tmp/161115b.gif

I find it fascinating that the Viterbi decoder, working in that
same bandwidth, is able to extract a message from the invisible
signal.

Have to increase the frequency resolution by a factor 10 before
the carrier can be seen by eye,

 http://abelian.org/vlf/tmp/161115c.gif

--
Paul Nicholson
--

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