> Not sure if everybody can really understand how weak ... was that signal ...
The attached shows close experimental and theoretical agreement on an
"attenuation summit" at ~ 17000 km at ~ 17 kHz; the hemispherical distance at
which the signal is weakest, past which it is downhill (increasing signal
strength) to the antipode.
It's thrilling to see this summit reached with minimal (low size/weight/power)
equipment.
Future reference: the attenuation descent to the antipode* is a bit rocky with
interference nulls (from the opposite-direction signal).
* is this on Stefan's list? :-)
Well done Stefan, Edgar, Markus, Paul and all.
73,
Jim AA5BW
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Paul Nicholson
Sent: Friday, September 14, 2018 4:24 AM
To: [email protected]
Subject: Re: LF: RE: New experiments on 17.47 kHz planned...
> Not sure if everybody can really understand how weak and > buried in noise
> was that signal ...
1.6 info bits per hour across a 16800 km path, 42% of the Earth's
circumference, using 2mW, much less than the power of a small LED.
S/N -65 dB in an audio bandwidth.
Not a bad result there, at a range of 183727 American football stadiums.
Added to http://abelian.org/vlf/amateur-radio/
--
Paul Nicholson
--
Antipodal Focusing 14.7kHz-20kHz Experimental & Theoretical 10kM-20Mm .pdf
Description: Adobe PDF document
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