Dave said:
Hello Frank,
The oscillator is an attempt at a very basic signal generator, for the
purpose of determining the Q of the inductors in the tuning circuit of an
active shortwave antenna. Now that you mention it, the counter did
function properly when I had a xtal in the oscillator... Back to square
one- how to stabilize the oscillator. I will try your suggestions of
attenuating the signal, and decoupling the counter. Those are two things
I would have never thought of...
Many thanks,
Dave
Well, a squirt of contact cleaner on the sensitivity adjustment knob (from
the outside, I'll take it apart tomorrow and do it right) helped a little,
but the decoupling capacitor had no effect, and I already had a 100K
resistor between the stator of the active antenna's tuning capacitor and the
frequency counter's input and as I recall that did help a little also. Now
fluctuates less wildly, but still too much to tell what's actually going on.
About to put it to bed for the night, and pick it up again in the morning.
Thanks for the ideas though. If you think of anything else, please don't
hesitate to suggest it. I apologize for being so ignorant about RF.
BTW, the freq counter is an autoranging model, with a 1 second, 10
millisecond and auto positions as well as a sensitivity adjustment. As I
mentioned, it counts at least to 100 MHz, but more than that I don't know.
It was a gift from my brother in law about 25 years ago, and it wasn't new
then. I suspect it was his first frequency counter.
Thanks to all. Sorry for the frustration...
Dave