In article ,
w5kcm wrote:

"Gimmick" capacitors are only good for a few pf, and are
used to do light coupling or introduce
feedback/self-oscillation. even if you could build one, it
would be pretty unstable for test use. =A0220 pf is
substantial (an air capacitor would have many plates). =A0In
the day, we'd use silver-mica type capacitors for stability.
=A0 If other friends' junque boxes are available, I'd try
those. =A0Thank goodness for modern meters--at my age, reading
the color codes is hard!

Yes, the more I have lookad at it 220 pf would be too large for a
gimmick. I will keep digging in the junque box, maybe find a few other
values to series or parallel to get close to 220 pf.

Gimmick caps in that range are probably made from sheet metal cut out of
tin cans. I find Altoids tins work well.

Use a cheap DMM with a capacitance function to measure them... then cut
them down until the value is correct.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."