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Date: Wed, 12 Oct 2011 20:20:15 +1100
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From: Dimitrios Tsifakis <dtsifakis@gmail.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: noise on VK and earth dipole tests
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Hi John,

2011/10/12 John Rabson <john.rabson@numeo.fr>:
> Amongst other things, it depends on the geology. =A0G3XBM has managed 5.6=
 km with 5 W RF at very low frequency. =A0On 87 kHz with 4W SSB (cave radio=
) in limestone, the best I know of is 1.6 km two way and 2.5 km one way in =
the French alps.

Well, the S/N required for voice is much higher than that of QRSS30.
With a puny 3 W of RF and QRSS30 it seems I can cover a distance of
about 30 km and still have a S/N of 30 dB! Which implies that possibly
(if the signal received is normal ground wave, similar to that from an
above-ground antenna), with a spreading loss of 6 dB per doubling of
distance and with a bit more juice, much greater distances may be
covered.

> It is always worth trying.

That's the spirit in the amateur world of LF! :-)

73, Dimitris VK1SV