[time-nuts] Trimble OCXOs - 6525, ... and ...

Alex Pummer alex at pcscons.com
Sun Jul 6 23:45:15 EDT 2014

some older models have higher phase noise, the very new ones are very 
good, sometimes they aged out the control voltage range, needing higher 
control voltage to pull to 10,0000000 MHz, some of them can not be 
pulled to the correct frequency any more without mechanical 
readjustment. They have inside a trim cap to set the tuning range, which 
is not accessible without opening the case.The case is hermetically closed.
Some companies for very high performance units  filling the hermetically 
closed case with nitrogen, also reducing the pressure of the filing  gas 
bellow the atmospheric level.

On 7/6/2014 7:43 PM, Chuck Forsberg WA7KGX wrote:
> On 07/06/2014 05:38 PM, Philip Pemberton wrote:
>> Hi there,
>> I've noticed a couple of Trimble OCXOs listed on "that auction site". 
>> Specifically, model numbers:
>>   - 65256
>>   - 49423
>>   - 34310 C1
>> They all seem to be 12V, 10MHz, sine-wave units. Does anyone know if 
>> there are any other differences between them? Do any specific ones 
>> perform better than the others?
>> There's a bit of a price difference between them, but data on Trimble 
>> OCXOs seems to be quite sparse (a bit like data on their GPS modules, 
>> really).
>> Thanks,
> I bought a replacement OCXO for a Thunderbolt whose OCXO had died.
> The pinouts are different.
> The housing is much taller and won't fit in the Thunderbolt enclosure.
> The polarity of the VCO pin is different.
> That said, I was able to get the kluge to work by changing the 
> polarity of the loop gain.

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