WB6BYU
The IF transformers may have a limited range
of adjustment, depending on the design. I’ve
tried some that would only tune 10 kHz or so.
In that case, you may need to remove the
internal capacitor and use an external one
of a slightly smaller value
I going to try the Xicon 42IF100-RC transformers, which have no internal capacitor. Spec sheet says center frequency is 796 kHz with a primary inductance of 360 uH at 455kHz. Hopefully I can get them to work. Only about a buck a piece and they are actually in stock at Mouser. And for now I'm going with the Collins 500 kHz filter I got on eBay. If I can get this IF section working, the rest should be pretty straightforward. Famous last words!