[time-nuts] HP/Agilent 5065A Rubidium Vapour frequency standard problem

service at frequencystandards.com service at frequencystandards.com
Thu May 8 13:59:58 EDT 2008

You didn't really say in your description but you really need to have the
loop open using the front panel switch before you try to adjust the
oscillator. Unless you are very familiar with how tiny of a turn it takes
to make it too far off to lock, you will have it out of range very
quickly. Open the loop and connect the 5Mhz output to a good frequency
counter, preferably one that is synched to another rubidium, GPS locked
crystal or cesium. Once connected, adjust your crystal coarse adjust for
as close to 5Mhz as possible. If you can't get it below a 0.1 hz error,
you are going to have trouble getting the unit to lock. Make sure you
allow a good warm up time for the crystal in the 5065 before you do any
If you can get the crystal to that small of an error, then close your loop
and watch the control meter setting. Typical is that the meter will move a
small amount but not peg. If it pegs, you have another problem with the
unit. If it moves a small amount and stops, you can then adjust the coarse
or fine and bring the meter back to zero. If you use the coarse adjust, at
this point, you are going to be making VERY tiny adjustments of it.
Let us know what you find from this and we can move you to the next step.
Chuck Norton

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