From: "Mike Dennison" <mike.dennison@rsgb.org.uk>
Organization: Radio Society of Great Britain
To: rsgb_lf_group@blacksheep.org
Date: Mon, 28 Jun 1999 09:45:35 +0100
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Subject: Re: LF: Field strength measurement....Rik
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Alan Melia wrote:
>     I have been grappling with the idea that I need to know how good (or how
> bad!) my antenna is on reception. After several months of listening and
> slight changes I know it isn't good enough...but how do I know if I have
> built a better one or improved it?

I use the simple method of monitoring LF beacons close to the 
136kHz band, notably the DCF beacon on 138.82 and the Greek 
RTTY just below 136kHz. The German one is remarkably stable on 
ground wave, but has a useful sky wave component after dark. The 
Greek signal is almost completely sky wave (it is audible 
sometimes all day) but has a stable maximum strength on most 
days.

These give a practical measure of how good the antenna is at a 
distance which is really what is required.

Of course, if it is purely receiving you are interested in, the signal 
to noise is more important than simple signal strength, but I can 
also measure the relative noise level on the S meter (when local 
QRM generators are off - an increasingly rare occurrence).

As a 'ball park' figure, DCF should be several tens of dB over 9 and 
the Greek RTTY should be S9 (at night) for a noise reading of less 
than S3.

Mike, G3XDV (IO91VT)
http://www.dennison.demon.co.uk/activity.htm