From: "James Moritz" <j.r.moritz@herts.ac.uk>
Organization: University of Hertfordshire
To: rsgb_lf_group@blacksheep.org
Date: Mon, 17 Sep 2001 12:29:22 +0000
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Subject: LF: 135.923 antenna tests
Message-ID: <E15iwXw-0002um-00@gemini.herts.ac.uk>
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Dear LF Group,

Thanks to Brian and Alan for the reports on my test signals on 
Saturday night. I was trying out my new field strength measurement 
system as a prelude to doing some more antenna tests this winter. 
I am now using a W&G SPM-3 level meter, with a tuned ferrite rod 
and preamp, which I have re-built to mount on my car. I can now 
rotate the antenna and take readings from the driver's seat (not 
while in motion though!), which makes field strength measurement 
much quicker and easier - I was able to get 30 readings in a couple 
of hours at distances between 1 and 8 km. I used a GPS receiver 
for position measurement. 

Transmitter power was around 150W, giving 2A into my inverted L 
which has about 8m effective height. The calculated ERP is 
150mW . The field strength measurements gave an average ERP 
of 66mW, which is in line with previous measurements.

The cherry picker I was using last winter to support my antenna 
has now returned after it's summer migration, so I intend to do 
some comparative tests with antennas of different heights, and 
also on 73kHz, over the next few months.

Cheers, Jim Moritz
73 de M0BMU