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Old 19th Jan 2023, 3:12 pm   #120
Bazz4CQJ
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Join Date: Apr 2009
Location: Oxfordshire, UK.
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Default Re: Improving Selectivity In Vintage Receivers

I've been pursuing this area of interest by getting a wobbulator and sawtooth generator constructed, and those are now near to completion.

With those available, I was wondering about how best to start to learn a little about how the ceramic filters work in-circuit (and how wobbulators work ). I've extracted an old Pye Vanguard IF board from the junk box and think it might make a useful testbed (at least for transistor circuits).

The attached figure shows the IF stage and is marked up to show some positions where I thought filters could be installed. I think the AGC should be disabled and the winding that feeds MR2 used to take an RF output from the board.

Any thoughts?

B
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