"Litzendraht" wrote in message
oups.com...
Yes, they are just coils that are enclosed in ferrite pot cores to
make them "Hi-Q". You have found the threaded rods sticking out each
side. This is how you vary the frequency of each coil.

The last time I fooled with it, I recall that it had a pretty wide
tuning range up and down from 230 kc. Each coil winding has a dipped
silver mica cap across it's terminals underneath. I can't imagine those
caps drifting in value.

I agree with Don that you should probably align it in the "narrow
"position. Is it .6 kc? I think.

How accurate is your test equipment?

John

I have a RCA WR-50B signal Generator which I checked against a BC-221
hetrodyne frequency meter set at 230Kkc. I had previously checked the
internal 2mc crystal in the BC-221 against wwv. I also have a old
Heath/Schlumberger counter with 2 ranges that are too high and too low for
230kc. The high range indicates .230 mhz with the zero flashing 1 and the
low range indicates overflow and reads 29.942
The manual does say to align at the narrow, 6kc, bandwidth position.
Maybe some other external component is affecting it. I also have a hard time
thinking any mica caps have changed value especially since it seems they
would have to increase in value to cause the problem. There's a couple
molded paper bypass caps in the circuit.
John