[time-nuts] 10MHz Rubidium reference source for frequency counter

Angus not.again at btinternet.com
Sun Nov 2 15:56:18 EST 2014


On Sun, 2 Nov 2014 12:13:34 +0300, you wrote:


>Mode has been switch from Frequency to TI - result is much better now. It was the main improvement in my measurement. Thanks a lot!
>Picture of ADEV OCXO result - https://dl.dropboxusercontent.com/u/21338179/hamradio/OCXO_Adev/OCXO%20ADEV%20TI%20mode%2020141102.jpg


Hi Karen,

You appear just to be measuring the ADEV of your counter in single
shot TI mode here, not the oscillators - how exactly do you have the
counter and oscillators connected up?

If I was doing it I'd probably try start by setting the counter to
measure freq in Smart Freq mode, and set it to ext ref, with one
morion feeding the external reference and another on the input. If the
morions are ok you should get towards 1E-11 at 1 sec (if I'm reading
the specs correctly) If not, try other oscillators and see if anything
changes.

As John said, TI is more complex to do anyway, and with quartz that
has not had days or even weeks to settle it's a total pain.

Angus





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