[aprssig] Re: Multiple Radio Desense

Jim Lux jimlux at earthlink.net
Tue Mar 15 18:34:55 CST 2005

From: "Robert Bruninga" <bruninga at usna.edu>
>>> "Jim Lux" <jimlux at earthlink.net> 3/15/05 5:50:37 PM >>>
>> The antennas were dipoles in free space with an assumed
Yes we just assumed 40 dB Antenna isolation as a ball park
benchmark.  Two physical antennas 100 feet aprart can have
values +/- 6 dB or more depending on everything around them.
THus, we did not intend to be rigiorous, but just take an
assumed 40 dB isolation...

>A good test would be to use a high quality signal
>generator as the jammer.. then you'd know it was a
>receiver problem, not a Tx spurious signal problem.

Yes the tests were done with two signal generators
and a splitter.  Then extrapolated to "two antennas
about 100' apart" by adding 40 dB.

 Now I see. you were modeling the 100 foot separation and radios, you
weren't reporting the results of a field test.
Since we were both modeling based on some lab tests of the radios, it's not
surprising that the results are similar.

Jim, W6RMK

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