In the old days military sites had the receiving equipment and antennas a
few miles away from the transmitting site to avoid a number of problems.
Naturally receivers those days were easily overloaded by off frequency
signals.
73
Bill wa4lav
At 04:46 AM 9/7/2007 -0400, Peter Chadwick wrote:
>Over the years, this has been a well known problem on ships at HF,
>especially where they run full duplex telephony. Not that many do these
>days in the commercial field, but the military have a lot of experience of
>these effects. Somewhere I've a conference paper given some 20 odd years
>ago from the UK MoD people on the subject, which told how they traced it
>on anumber of ships. I remember them having a problem because in some
>cases, below a certain power level it disappeared abruptly.. Fortunately,
>the characteristics of tetrodes generally make the transmitter a
>negligible contributor, but the external environment is another matter.
>Worse at sea, of course because you've got continuous corrosion!
>
>73
>Peter G3RZP
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