[TowerTalk] receiver protection

[Pete Smith]

I am looking at a design for receiver protection in an SO2R environment 
that involves a series resistance (#49 bulb) and stacks of back to back 
diodes shunting the receiver input.  The objective is to protect front-end 
components against strong out-of-band signals, but in the process I don't 
want to incur an intermod penalty under normal operation.

If I stack 3 diodes in each direction, the forward conduction point will be 
2.1 volts.  Is that high enough to avoid generating intermodulation, except 
under circumstances where I wouldn't be able to hear anything anyway?  I 
figure that much voltage at a 50-ohm receiver input terminal to be 
something like S9+80dB.

Thanks for your advice.

73, Pete N4ZR
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