> This leads me to a question that I have had on my mind. How
> are people
> doing desense testing with D-Star systems? (Remember, it's digital.)
>
> 73, Joe, K1ike
How about this - record a clean D-Star transmission (not decoded, just the
"raw" output from an FM receiver) on a PC with a good sound card, then use
it to modulate the sig gen in your service monitor. Do desense test using a
lossy tee like you normally would, except instead of comparing 12 dB SINAD
points, you'd have to rely on listening to the repeated/decoded audio on
another radio to gauge performance.
To establish the baseline receiver sensitivity reference, disconnect the
D-Star transmitter from the antenna system and run it into a dummy load.
While listening to the repeater output on another radio, adjust sig gen
output until you get clean decode sans R2D2, record the sig gen output level
as the baseline. Then reconnect the transmitter to the antenna system, and
repeat. If you need to increase the sig gen to get clean decode again, you
have desense obviously.
This isn't an ideal way to test, but it's better than nothing lacking real
D-Star test equipment.
Is there any way to get pre-FEC and post-FEC BER metrics out of a D-Star
repeater or user radio?
--- Jeff WN3A
