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Heath Zenith SM 2420 frequency meter
#1

I don't know if it happens with all of them.When I start aligning, everything goes nice and smooth. Then I start lowering the signal strength by attenuator.At the certain point, the reading on the meter goes berserk. It shows less or more, whatever. I know that the correct frequency is still there, but still it's uncomfortable, as my generator is Eico 315 and known for floating,especially at MHZ range. Is there any way to rectify that?
#2

The frequency counter has a minimum signal level requirement and once you go below it, the reading will be unstable or fail to read at all. Not much can be done about it. Just set the freq as best you can and then reduce the attenuator as necessary. Periodically you can increase the signal to confirm that it has not drifted off freq significantly.
#3

Yes it is normal.
But you do not need measure the frequency all the time.
What I do is (my oscilaltor is a tube one) - I let it warm up for 5-7 minutes, and then I set up a frequency on a stable signal and then I simply switch the signal to radio and no longer measure the frequency, until I need to change it, at which point I repeat the process.
If your generator is stable there is no need to constantly monitor the frequency.




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