That explanation doesn't make much sense to me.
Are you sure this discussion is not relating to VHF "repeater" systems,
which are transmitting and receiving simultaneously at each site?
Then, the RX impact can be disastrous if the antenna match degrades, due to
the immediate desense that occurs when a duplexer is terminated in a
mismatch. That would be perfectly normal. But for a "simplex" system,
where each station is only transmitting, then receiving, my observation is
that the TX is usually more affected than the RX.
WB2WIK/6
"If everything seems under control, you're just not going fast enough." -
Mario Andretti
> -----Original Message-----
> From: steve sala [SMTP:stetrekve@yahoo.com]
> Sent: Thursday, November 21, 2002 11:43 AM
> To: Towertalk@contesting.com
> Subject: [Towertalk] high SWR at receiver inputs
>
> 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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