Message-ID: <389D4249.43C5@xtra.co.nz>
Date: Sun, 06 Feb 2000 22:43:37 +1300
From: "vernall" <vernall@xtra.co.nz>
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To: rsgb_lf_group@blacksheep.org
Subject: LF: Frozen ground
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Hi all,

I was not able to find a reference text to eyeball myself, but Andrew
ZL2BBJ has supplied the following references about measurements for
losses for snow and glacial ice.
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Watt, "VLF Engineering ", Peramon Press 1967, pp 85 - 87 for effect of
snow 
over buried ground mat, and p 183 for ground conductivity constants.

Watt cites Watt A D and Maxwell E L "Measured electrical properties of
snow 
and glacial ice", NBS J. Res. Vol 64D No 4 , July-Aug 1960.
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It continues to be my understanding that frozen ground is much more
lossy than unfrozen ground.  Copper radials may "save the day" at the
antenna site itself, but ground wave propagation beyond the antenna site
would encounter natural ground conditions and whatever losses arise can
not be avoided.  If skywave radiation "took off" from the antenna site
(which it likely does) then a skywave path would not be so affected by
frozen ground somewhat away from the antenna site.

73, Bob