[aprssig] Re: Multiple Radio Desense

Robert Bruninga bruninga at usna.edu
Tue Mar 15 15:50:48 CST 2005

>>> jimlux at earthlink.net 3/15/05 3:27:46 PM >>>
>>Last week, I asked 3 AMSAT volunteers (OE1DMB, N6IZW,
>>and ZL3RX to take some radio measurements for FM desense
>>just to see if we were in the ballpark for multiple radio
>>operations at one site....
>This is handy, except that you didn't tell us what kind of 
>radios, and what kind of antennas... and where they were 
>relative to the ground.

5 different radios were tested and though there was some
diferences, we reported the range from the best to the worst.
The antennas were dipoles in free space with an assumed 
40 dB isolation (49 db for UHF).

>How did you define "desense" and "blockage"?  

Blockage was when the original signal was no longer heard.
This was a voice or tone test, not a packet test.

We just wanted to give a ballpark value of the general 
concept of blockage by inband operation between two


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