[time-nuts] Calibrating a HP 5370B Oscillator

Perry Sandeen sandeenpa at yahoo.com
Sat Nov 5 03:39:47 EDT 2016

Wrote:I am the proverbial man with too many clocks and I don'tknow what time

it is.

To correct this situation I have decided to calibrateeverything.

I have a HP 5370B, a HP6370A, and a HP 5328A all with the TCXO 

option. <Snip>
Hi Peter,
You can't really calibrate the 5370B oscillator.  I tried.
All that you can do is adjust the mechanical adjustment as the EFC pin is grounded on the edge connector.
I thought about making the EFC pin available but it required cutting some of the bottom sheet metal.  Then one would have to cut the trace on the MB and add a highly regulated PS for the EFC with an adjustment control.
Also the PS for the oscillator is primitive and would need to be upgraded.
IMNSHO, the reason they left out doing this is the variations of airflow rate, airflow temperature and vibration from the cooling fan.
In the 5370A they used a less expensive oscillator.
I think that in the B model HP just wanted better stability to achieve the better pico-second  resolution rating.
An interesting experiment would be to run the B, take the 10 MHz output and compare it to a GPSDO or Rb standard and see how many variances that would occur.
IMNSHO, I drive the B with an its 10811 externally powered in a better enclosure.
I cant comment on the other gear.

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