[time-nuts] Changing frequency of an HP 10811 oscillator

[J. Forster]

I have a 10.23 MHz 10811 oscillator out of an early GPS simulator
somewhere, so, FWIW, HP did make at least one. I remember it because I was
disappointed it was not 10.000 or 10.24 MHz.

Best,

-John

=================


> Several issues here:
>
> 1.  Making a precision crystal like the 10811 one is very involved.
> It cannot simply be rescaled to a different frequency.  It represents
> a whole new design.  This is not like ordering custom crystals for
> your 2 way radio (back in the day).
>
> 2.  The 10.23 MHz crystals I am going to give away (as time permits :-)
> were designed under duress by the crystal designers who did not want
> any part of the operation.  That's why I have a box of the crystals,
> since the project died.  Expect a similar "welcome" from crystal vendors.
>
> 3.  Many years ago, it may have made sense to have 10.23 MHz GPS
> time base oscillators.  Nowaways, it is much easier to synthesize
> frequencies and you don't see this any more.  Everthing starts with 10
> MHz.
>
> 4.  If you need 20.0000 MHz, then use a doubler as others have noted.
> If you need some "random" frequency, use frequency synthesis.
>
> 5.  The 10811 crystal is in a custom can, and you would have to kluge
> in any different crystal package.  This would probably screw up the
> oven gain, necessitating rebalancing the heater transistors.
>
> Summary:  (to use a technical term:)  fuggedaboudit
>
> Rick Karlquist N6RK
>
> On 11/21/2010 10:32 AM, Demian Martin wrote:
>> Having seen the note on alternate crystals for the HP10811 oscillator I
>> was
>> wondering if its realistically possible to re-crystal one to frequencies
>> in
>> the 20 MHz range? Some other components may need to be changed of course
>> but
>> is this worthwhile exploring? Who would be a good vendor for a few
>> custom SC
>> crystals that would work in an HP10811? I have been quoted prices in the
>> $500+ range for finished products and want to explore a more cost
>> effective
>> option before I spend a lot of money.
>>
>>
>>
>> Demian Martin
>>
>> Product Design Services
>>
>> San Leandro, CA 94577
>>
>> 209 613 6990
>>
>>
>>
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