From: "Mike Dennison" <mike.dennison@rsgb.org.uk>
To: rsgb_lf_group@blacksheep.org
Date: Thu, 8 Feb 2001 14:08:49 -0000
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Subject: Re: LF: Loran Lines.
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GW3UCJ wrote:

> Hello everyone. A simple query to give us all a rest from the hi-tech
> stuff. I've been listening on 137 for a year or so and in that time I
> have NEVER seen any Loran lines. People tell me that if I can't see
> them, I should get myself a decent receiver. I receive all the usual
> stuff OK, though I can't get any amateur signals outside UK/EI. I am
> using  a TS950 and an untuned 30m horizontal wire. 

Away from the south coast of England, Loran is not strong. 
However, you are right to regard them as a useful guide to 
sensitivity as anyone in the southern half of the UK should be able to 
hear Loran on a quiet day and see the lines on a spectrogram all of 
the time. The fact that you are not hearing anyone outside of G/EI 
tends to confirm that there is a problem.

I operate from Pembrokeshire from time to time, and can hear 
Loran on a loop as well as various wires, including fencing. I also 
regularly hear DL, HB and SM.

>From your description, it seems to me that you need to build a tuner 
for your wire. A random untuned wire will receive the strong amateur 
stuff, plus lots of extremely strong out of band signals which will do 
their best to inter-mix and produce what you see as 'noise'. It will 
also attract local noise such as those from TV timebase, SMPSUs 
and computer games.

Try winding a coil of a couple of hundred turns, liberally tapped, on 
a plastic bin. Earth one end, tap your receiver a few turns from the 
earthy end, and connect the antenna higher up the coil, taps 
adjusted for best reception of DCF on 138.8kHz.

Another thought is your earth. Do you have a reliable RF earth? If 
not, a single stake in the ground is likely to perform better than a 
connection to the mains earth.

If all this simply raises the noise level in line with the signal increase, 
try taking the tapped coil out for some portable tests as before.

Good luck.


Mike, G3XDV (IO91VT)
http://www.lf.thersgb.net