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
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