[time-nuts] HP5065B !!!

Bruce Griffiths bruce.griffiths at xtra.co.nz
Sun Apr 28 01:50:06 EDT 2013


Has anyone considered a laser pumped variant like:
http://tf.nist.gov/general/pdf/1009.pdf

Apart from the ECDL laser (can be assembled using readily availalble 
parts) it looks fairly straightforward.

Bruce

Tom Van Baak wrote:
>> Very nice bit of R&D work on Corby's part.  Mine is certainly working well
>> after the modification, but I'm just blown away at the performance seen with
>> Tom's unit.
>>      
> Hi John,
>
> Yes, apparently some 5065A respond better than others to Corby's clever mod. It's clear why there is improvement; it's an interesting challenge/mystery to understand why some get more improvement than others. I double checked its performance with both a TSC 5110A/5120A and your TimePod to be sure it wasn't me.
>
> In general, some HP 5065A are better than others. OTOH, this is somewhat true for any frequency standard: from pendulum to quartz to rubidium to cesium to hydrogen. It drives time nuts crazy (and turns some of us into eBay gold diggers) but this has been the case from the first hand-made quartz oscillators in the 1920's to, well, the hand-made GPS Rubidium's, or the hand-made cesium fountains of today.
>
> Every clock is slightly different. You can be practical and live with it, or a fanatic and keep searching for a slightly better one or finding out why and putting effort into tweaking parameters, swapping components, or boards, etc. I know Corby has done an amazing job over the years with vintage cesium and rubidium standards. I hope to have him upgrade some of my 5065A too.
>
> Just to clarify -- the excellent plot that Corby posted was a modified 5065A that I tested *for* him, not one that I actually own. So it's not "Tom's unit", but one that Tom enjoyed testing. Note the baseline was a PHM vs. AHM, just to show the noise floor of the measurement system(s) and reference(s).
>
> /tvb
>
>    
>> Another plot of the "Super" mod that's worth mentioning:
>> http://www.ke5fx.com/5065A_vs_maser_mask.png
>>
>> Below 1000 seconds it has no trouble passing the spec limits for a passive
>> H-maser!  For contrast, teeypical LPRO-101 performance is shown in green,
>> and the red trace is from the second-best commercial Rb standard I've seen
>> (Symmetricom XPRO).
>>
>> -- john, KE5FX
>> Miles Design LLC
>>
>>
>>      
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com [mailto:time-nuts-
>>> bounces at febo.com] On Behalf Of cdelect at juno.com
>>> Sent: Friday, April 26, 2013 8:24 AM
>>> To: time-nuts at febo.com
>>> Subject: [time-nuts] HP5065B !!!
>>>
>>> OK, that was just to get your attention!
>>>
>>> What do you call a modified HP 5065A that can give you an Allan Deviation
>>> of 4X10-13 @ 1 Second and 6X10-14 @ 100 Second?
>>>
>>> I call it the "SUPER" HP 5065A.
>>>
>>> Any of these links will get you to the document describing it.
>>>
>>> Have a look and see what it's all about!
>>>
>>> Enjoy,
>>>
>>> Corby
>>>
>>>
>>>      http://leapsecond.com/corby/Super-5065A-Project.pdf
>>>
>>> or
>>>
>>>      http://leapsecond.com/corby/superproj10.docx
>>>
>>> or
>>>
>>>      http://www.febo.com/pages/HP5065A_SUPER for
>>>        
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