There was a Bill Cheek scanner modification for EDACS that used a tone
decoder to force the squelch closed when a certain hold tone came on the
air. You need a 567 phase lock loop tuned to 2175 hz and have the output
force the carrier squelch logic off for a short time. You will probably
still get a blip of tone when the scanner passes that channel by. You
can filter the 2175 hz with a notch filter scrapped out of a MICOR base
station tone control card.

Joe

Rich wrote:

I want to receive a UHF frequency. It starts as a 33.84 receiver to a UHF
frequency and beamed to a microwave receiver. And down to the dispatcher.
We can get the UHF side but it holds the scanners squelched open it uses a
2175 Tone. What filter do I need to receive this channel?



Richard





--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"

"Follow The Money"