[time-nuts] Thunderbolt MV-89a OCXO Transplant?

[Götz Romahn]

Bob, mny thanks for your comprehensive explanation. Now I know much 
better ;-)
As for St. Petersburg: have been there in my pre-MV89 ages. Well worth a 
visit for some days, no bad guys on my ways.
Goetz

Am 28.05.2013 23:10, :
> Hi
>
> The MV89A's that are out on eBay are all custom built parts. The part
> numbers on them do not fully show what they are. About the only way to find
> out would be a flight to St. Petersburg (not the one in Florida) and a sneak
> look at their files. If the same guy is still in charge of security that was
> in charge on my last visit there ... not a good idea.
>
> Simple answer - it's a bit of a guess as to what you have once you get past
> the generic stuff. When a big OEM says "build it to this spec" that's what
> everybody does.
>
> Bob
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Götz Romahn
> Sent: Tuesday, May 28, 2013 1:12 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Thunderbolt MV-89a OCXO Transplant?
>
> Bob, how can I find out what the differences among various MV89 are ?
> thanks Goetz
>
> Am 28.05.2013 18:52, :
>> Hi
>>
>> The MV89A is a 5 MHz resonator doubled to 10 MHz, it will have sub
> harmonics
>> that the original OCXO (using a 10 MHz resonator) does not have.
>>
>> The MV89A has 10 to 20 db worse phase noise as a stand alone OCXO than the
>> original OCXO. That is masked to some degree by the TBolt's internal
> noise.
>> Depending on which MV89A you get (there are many flavors), it's
> temperature
>> stability will be 3X to 10X better than the modern versions of the TBolt
>> OCXO.
>>
>> The ADEV on the MV89A should be ~2X better than the modern TBolt OCXO.
>>
>> The tuning voltage range of the original TBolt OCXO is +/- 5V on the MV89
>> it's 0 to 5V. The pull range on the original is about 5X greater. Both can
>> be fiddled on the TBolt via LH.
>>
>> Check your TBolt board for the connection (if any) to the Vref pin on the
>> MV89. Shorting it to ground may not be a good thing. Of course your MV89
> may
>> or may not have a voltage on the Vref pin.
>>
>> Bob
>>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>> Behalf Of Frederick Bray
>> Sent: Tuesday, May 28, 2013 10:37 AM
>> To: time-nuts at febo.com
>> Subject: [time-nuts] Thunderbolt MV-89a OCXO Transplant?
>>
>> Looking at the archive, I noticed that several months ago someone
>> commented that the Morion MV 89A was a direct replacement for the OCXO
>> in the Trimble Thunderbolt in the sense that the Thunderbolt PC board is
>> configured to accommodate it.  However, I wasn't able to find further
>> details.
>>
>> I have a spare Thunderbolt and a spare MV89A and I am considering doing
>> the transplant.  Before I tear the Thunderbolt apart, I have a few
>> questions:
>>
>> 1.  Has anyone actually performed the transplant?  (Does it work?)
>>
>> 2.  Are there any significant drawbacks and advantages to the transplant?
>>
>> I am aware that the MV 89A may pull more current on the 12 volt line
>> than the Trimble and that the original Thunderbolt cover will no longer
> fit.
>> Thanks.
>>
>> Fred Bray
>>
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