From: "James Moritz" <j.r.moritz@herts.ac.uk>
Organization: University of Hertfordshire
To: rsgb_lf_group@blacksheep.org
Date: Wed, 20 Jun 2001 12:21:12 +0000
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Subject: Re: LF: 73kHz beacon/antenna problems
In-reply-to: <$HlFkHAs8EM7Mwi9@telemetry.demon.co.uk>
References: <E15CP5g-0000L5-00@gemini.herts.ac.uk>
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> Jim, M0BMU wrote:
> 
> > After lots of 
> >experimentation I ended up with only 75% of the original amount of 
> >wire I had in the air, but with about twice the original ERP for the same
> >TX power. 
> 
> How do you know this Jim? By far field measurements? Surely there can be
> no computer programme clever enough to take into account all the factors
> you mention like leaves on trees, building proximity etc.
> 
> 73, Tom G3OLB
> 
> 
Dear Tom, LF Group,

I wish there was a computer program that could do the job .... but I 
had to compare the antennas using actual field strength 
measurements. This involved a lot of driving around and setting up 
the measuring gear in odd places, mostly late at night, and got 
some very strange looks. Once, I was apprehended by a squad of 
security guards, who were convinced I was trying to eavesdrop on 
their radio communications for some dubious purpose - it took quite 
a lot of explaining away :-)

The 71.924 kHz beacon ran OK last night from 0005 until 0310utc  -
 I will give it a rest tonight, and try again tomorrow.

Cheers, Jim Moritz
73 de M0BMU