From Dave G3YMC
Many thanks for the information on CFH obtained from VE1FTL by Alan. Now at
least we know a little more about it. As Jon says it seems off the air at the
moment (it would now be quite audible when I listen before breakfast if it were
on).
I have done a quick calculation on a 200m loaded vertical using G4FGQ's program
and this shows that such an antenna, assuming 50 ohms earth resistance, would
have a radiation resistance of 13 ohms and an efficiency of 14.3%. A top
loading umbrella is likely to improve this somewhat (and the earth resistance
is likely to be quite a lot lower with a professional earth mat). Given the
typical efficiency of antennas most of us can use, and the limitation to 1W erp
I suspect this puts things into perspective!
<By the way, the 73.6 kHz transmitter is also located here in
<Newport Corner. It may be useful for monitoring openings on that band
Unless Rugby on 73.4 is off the air I think we can safely say the chances of
hearing CFH on 73.4 are absolutely zero!
Jon says the TX uses FSK. I remember noting earlier this year that at one time
it was transmitting FAX (clearly identifiable as such to anyone who has heard
FAX). Perhaps Jon has some information on this.
Cheers Dave G3YMC
[email protected]
http://ourworld.compuserve.com/homepages/sergeantd
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