TheRadioBoard

At the Silicon Valley Ham Fest yesterday, I bought a handful of TOKO inductors.

One is marked "16 0003" Singapore.

It has only two pins. There is a tubular capacitor in the base. It seems to resonate around 400 KHz. When I smash the capacitor, I can measure the inductance at about 600 uH.

Can't figure out what this was used for? Too low to be a local oscillator coil for a transistor radio.

Maybe a BFO coil for 455 KHz. ?

Rich

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Homebrew Radio ex-Silicon Valley

Probably, yes.
The capacitor in those transformers is 180pf (seen also 220 pf somewhere) which would have just the right value to get very close to 445 KHz with a 600/680 uH coil.

Here are some data about (some) TOKO IF cans. Hope they help.

http://www.bec.co.uk/PDF/10ez%20full%20copy.pdf
http://hem.passagen.se/communication/ifcan.html

Thanks,

I already had the second link but the first was new and I downloaded and saved the PDF.

Apparently, TOKO no longer sells IF cans?

Rich

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Homebrew Radio ex-Silicon Valley

Yes, they were phased out in favor of much smaller tunable inductors years ago. Today most radios use smaller fixed transformers or ceramic filters where possible.
The price of ceramic filters has dropped lately, so 100% coil-less IF stages could be possible.

Regrettably, progress does not help me.

I crush the internal capacitors and use these as adjustable inductors in homebrew shortwave receivers.

My first design used a 455 piezo filter, but I went back to an adjustable IF transformer. For the NE602, I think the balanced output is working better.

Rich

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Homebrew Radio ex-Silicon Valley