djl at montana.com
Sat Nov 22 15:55:24 EST 2014
Hi Bob: no. cobble, not double :-) A little research has me thinking I can
easily adapt a morion. I can try it at least by starting with the morion on an
external power supply and patching the output and control voltages in to the
The sr620 has a control circuit which apparently accomplishes your
suggestions; they claim to use the internal oscillator for short term and
"lock" it to a supplied external source for longer term. Probably has a long
time constant on the built-in phase lock to do this.
Anyhow, autocal calibrates everything except, guess what, the 10 mhz source.
Thats done separately.
So a bootup self check shows OK even if the frequency standard is way off.
Onward and upward.
> I believe that the SR620 uses a “true” 10 MHz OCXO. I would be careful using a
> 5 MHz doubled to 10 OCXO. The counter may or may not be happy with
> sub-harmonic induced jitter.
> Best bet at the specs:
> +12V power
> 0-5V EFC
> Sine wave out +7dbm
> +/- 5x10^-9 0 to 70C
> Pinout - trace what you have.
>> On Nov 21, 2014, at 6:59 PM, Don Latham <djl at montana.com> wrote:
>> So, I got a reasonable deal on a SR620 ho ho. Know your dealer. The ocxo is
>> out of tolerance. All self tests pass with flying colors, autocal works as
>> well. So the best parts are OK.
>> Does anyone:
>> 1) have a spare Isotemp OCXO36-53 10.000 MHz p/n 6-00051?
>> 2) know the specs, ie the input voltage/current and the control voltage span
>> and direction? pinout?
>> I have some Morion mv-89's and could easily cobble one in if it will work.
>> Apparently a correct oscillator must be in place to use an external source,
>> I read the manual right.
>> 3) do we have a source for the schematics for the SR 620?
>> The FTS 4060 is up, pumpin' and firmly locked. At least for now. That dealer
>> was not lyin'
>> Much thanks to all of you.
>> The adventure continues
>> "The power of accurate observation is commonly called cynicism by those who
>> have not got it."
>> -George Bernard Shaw
>> Dr. Don Latham AJ7LL
>> Six Mile Systems LLC
>> 17850 Six Mile Road
>> Huson, MT, 59846
>> mail: POBox 404
>> Frenchtown MT 59834-0404
>> VOX 406-626-4304
>> Skype: buffler2
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"The power of accurate observation is commonly called cynicism by those who
have not got it."
-George Bernard Shaw
Dr. Don Latham AJ7LL
Six Mile Systems LLC
17850 Six Mile Road
Huson, MT, 59846
mail: POBox 404
Frenchtown MT 59834-0404
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