Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

There is nothing magic about this circuit! It is a duplicate of the one
in ∗_QST_∗, December, 1969 pg. 11, or the 1970 ∗_Radio Amateur's
Handbook_∗, pp. 557-558 - which also gives the calibration procedure.
I've built several of these over the years - used just any ferrite
toroid core available that would pass the co-ax through the center -
you're going to have to calibrate it anyway. Any trimmer cap will work
- ceramic, mica or air dielectric - just keep it small and use the
shortest possible leads. Diodes? 1N34 from Radio Shack will work - in
fact they're called for in the reference articles. If you can't find
the feedthru caps, pass a wire through a hole in the shielding, and
bypass on the side away from the RF section. The only reason to
slavishly follow the pictures is if you are doing a restoration for
complete authenticity. Put the works inside a box that resembles the
original, and who (besides yourself) will know the difference?

The magazine or book should be available from larger libraries - maybe
on eBay - or from members of your local radio club. If you are
desperate, contact me off-list and I'll e-mail you the two pages.

Norm
W6NIM


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