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

[Paul Nicholson <vlf0403@abelian.org>]

> The message is correct. It is the first digi mode
> message on 6.47 kHz.

Close to the limit and could not be done with any other
mode.  The average signal was only 15dB in 19.5 uHz!

But at least we now have a stake in the ground at 6.47, I can
probably squeeze another dB out of it after some more tweaking.
Plus, it was a noisy summer night.

I'll have a look now at your 6480 carrier to do some more
adjustment.

Continuing to try for your first message but I'm probably
still 2 or 3dB short.

The day/night phase change isn't a problem, interesting that it
isn't less than at 8.27 kHz but it's complicated at these
short ranges.

Markus I hope you can get the rx away from that railway!
Even if you can find a gap in the harmonics, you've still
got the nearby harmonics restricting the action of the
sferic blanker.

--
Paul Nicholson
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