I'm looking at a project from the 50s that uses 1500 Khz IF transformers. I haven't been able to locate the Millen type specified and don't have a good feel for the input/output impedences. I began wondering if it was possible wind a toroid core bifiler to use for this purpose - with variable resonating caps to use for peeking. Has anyone done something like that?

arnie - W1GCI

No, way too much coupling doing it that way. You can do two individual LC resonant toroids and use a 1-2 turn link on each to couple them. That still gives pretty tight coupling but it might be ok depending on your application. Next step would be adding a small cap in series with the link.

Not too long ago one of the guys here posted a question about some 1500-1600 xfmrs that he fell into. I was waiting for a FS ad to show up because I would have been interested. Never saw it. Might be able to search back and contact him?

The early single conversion cb radios used 1650 KC IF's. eBay generally has some junkers listed that go cheaply. These transformers will probably tune 1500 KC unmodified. If necessary, add a small amount of capacitance across the windings.

Darrell

Arnie

How about working with AM broadcast band antenna coils?

Thanks to everyone that replied. I wasn't thinking about the coupling requirements. Jack's idea about using two cores and link coupling the two together seems like a really good approach. I think I'll give it a try.

arnie

I have a virgin Miller, Cat. No. 612-W2 Iron Core 2nd I.F. 1400-1600 KC

It's a 1"x1"x3" can with two adj. screws

Yours for the asking.

Ed