Hi All, I am trying to build a circuit to roll of the discriminator audio coming out of my UHF Mastr II receiver. I have one of those controllers that does "smart squelch" by paying attention to the high frequency noise and it seems the Mastr II receiver does not have adequate filtering to stop the 455khz IF frequency.
The manufacturer says this is a problem they are aware of with Mastr II's and recommends a 10 mH inductor in line with a 1000 pF cap to ground to get the discriminator audio to roll off far under 455khz. Now, I'm pretty new at this so am not sure exactly what I'm looking for in a 10 mH inductor. I have found locally some "high current RF chokes" rated at 10 mH inductance, and when I search on Mouser for a 10 mH inductor it returns many thousands of results. The cheapest thing I can find on Mouser is a tiny through-the-hole component to mount on a board and has a small current rating, but I suspect this would be fine for this purpose. Has anybody out there built such a filter to handle the 455khz IF frequency in the Mastr II receiver before, and could you recommend more specifically what kind of 10 mH inductor I'm looking for? Thanks much Mark Hagler W7WMH Seattle
