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Message-ID: <3.0.6.32.20000324120607.008172f0@pop.saunalahti.fi>
Date: Fri, 24 Mar 2000 12:06:07 +0200
To: rsgb_lf_group@blacksheep.org
From: =?iso-8859-1?Q?V=E4in=F6_Lehtoranta?= <vaiski@dlc.fi>
Subject: LF: GW F-s versus Wx parametres
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Working on the material left by ex YLE Meas station...
Does anyone know the email address of C. Gordon Van Aruan
whose article "Influence of Atmospheric Humidity on
Low-Frequency Radio Ground Waves" is on the pages 2.5-2.7
of "the LF Experimenters's Source Book", 2nd Edition.

Let me refer to another article in Proc IRE, April 1948,
"Temperature Variations of Ground-Wave Signal Intensity
at Standard Broadcast Frequencies" by Frederick R Gracely:
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"Ground-Wave signal intensities at standard broadcast
frequencies exhibit considerable variation, even over
short paths. ... The practical result of such variations,
regardless of the physical explanations ultimately involved,
is equivalent to changes in the EFFECTIVE CONDUCTIVITY OF
THE PATH. Therefore, in cases where the consideration of
close margins in conductivity measurements is necessary,
the variations produced by changing conditions over the
path may become exceedingly important. ...

Careful comparisons of signal intensities with many sets
of data on temperature, precipitation, humidity, atmospheric
pressure, dew point, and vapor pressure showed clearly that
there was closer and more continuous correlation with 
TEMPERATURE than any other single type of data."
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As we have been making these GW F-s measurements for more
than 50 years, would like to ask whether other persons on
this reflector have professional type of experience with
these F-s variations?      73 de Vaino, OH2LX


----------------------------------------------------------
V.K.Lehtoranta, OH2LX, POBox 50, FIN-05401 Jokela, Finland
------ Tel: +358-9-4173965 ---- Fax: +358-9-4173961 ------
E-mail: vaiski@dlc.fi - alias: oh2lx@dlc.fi & oh2lx@sral.fi