Friday, June 05, 2009

Airband squelch

....Did you think there was no provision for a squelch? Of course not! It's the most important feature of any receiver!
This schematic came from an online bigger schematic, I just change for what I need.
I will only test at the end but looks really simple and should work... or not.

Placed the IC and components in the audio amp board since there was space there and there's no need to make a board only for a simple circuit.

The squelch part is the one on the left in the photo in the right part is the audio "filter" and "power" amp.

There's 2 components missing (and forgot to place the 10M resistor) that I had none in the shack, 4k7 resistor and 10k pot. Must go shopping, my stock is getting dangerously low. I did think of replacing the BC183 for an BC547, but I found 2 around, probably 20 years old... hope it works :) gain was 193 (I think) on my tester.

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