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Re: VLF: EbNaut 8270.1 Hz, carrier 8270.0025 Hz

To: [email protected]
Subject: Re: VLF: EbNaut 8270.1 Hz, carrier 8270.0025 Hz
From: Paul Nicholson <[email protected]>
Date: Sun, 22 Jan 2017 21:28:21 +0000
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Markus wrote:

> I assume that was obtained by undoing the known keying and then
> measuring carrier SNR?

Yes, conveniently the Linux version of ebnaut has some options for
doing that.   It reports the phase too, which I forgot to mention:

 21st: -68.4 degrees
 22nd: -64.4 degrees

Coil Q factors have all sorts of strange variations, especially
when they couple to their environment.  Q factor can change
significantly on a time scale of minutes especially in icy
conditions.  We would expect Q to rise as temperature falls
but sometimes it does the opposite.  Several years ago I was
involved in some long experiments which automatically measured
and logged the Q factor of several resonant modes of Tesla coil
solenoids.  We recorded a lot of variations which were difficult
to explain.

Paul Nicholson

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