"Dave Platt" wrote in message
...

snip

I don't think there's any problem with using these sorts of cables in
commercial or amateur service in *simplex* applications... they can
handle transmitting, or receiving, just fine. It's only when you try
to do both, simultaneously, through the same cable. that the noise
generation can become a problem.

The same can be true of some classes of antenna problems. The
repeater system I help maintain developed a serious desensitization
problem, due to internal corrosion/oxidation which occurred in the
antenna after several years up in the weather. I doubt that the
corrosion/oxidation effect would ever have been noticed if the antenna
were in service as a normal (simplex) base antenna - it didn't affect
the transmit SWR or the receive sensitivity at all,

All metallic contacts are potential problems. For years I did Navy
electronics, including a couple hundred EMI inspections. Where "topside
housekeeping" was neglected, broadband noise (BBN) was sure to be a problem.
(All topside metallic objects need to be either insulated or firmly
connected -- no incidental contact.)

As little as a hundred watts would excite some junctions to generate BBN
that could be detected throughout the HF band on other antennas. More power
would generate BBN up to several hundred MHz. Been there.