A coworker asked me this question since I was a ham.
He has noticed this with several radio system
installations. There have two identical radio systems
communicating with each other, same two transmitters,
receivers, coax and antennas. And it is on vhf so
there is no skip, maybe a few miles apart - Normal
good communications, transmitting data either by dtmf
or by fsk.
He says that if the swr goes high on one antenna
system (maybe due to an coax/antenna malfunction), the
system behavior could be as follows: The radio signal
from the system with the high SWR antenna system will
still be received at the other station fine, but the
receiver (at the high SWR antenna system) could have
receive problems due to the effect of high SWR at the
receiver input.
The other radio system, with no SWR problems, will
still receive fine from the transmitter with the high
SWR and transmit as usual due to its low SWR.
In other words, he notices problems at the receive end
of the system with the high SWR problem first.
My justification for this happening is that you can
normally lose a lot of transmitter power and still be
received, yet the receive portion is more critical.
There is less room between good reception and bad
reception (the noise floor) since you are playing with
microvolts.
Could I get a few comments on this from any of you
whether we are on track or not.
Steve K7AWB
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