[time-nuts] HP 5061Cs reference question

[paul swed]

The system does consistently come to lock with a constant offset. So its
finding something. Just the odd little offset thats bugging me.

On Sat, Dec 6, 2014 at 2:48 PM, Magnus Danielson <magnus at rubidium.dyndns.org
> wrote:

> It's a challenge indeed. IF you are running on fumes, it will be harder
> for the automatic locking to find first and second modulations, and if it
> does this, it is much more likely to be the central pedestal as the others
> will be even further down into the noise. The lack of the fundamental tone
> will cause that FLL may fail to lock, since the sweep signal can be too
> strongs, and if it does lock, it will be weak as the loop gain will be off
> by the lack of signal and then naturally the S/N will be problematic.
>
> Not sure that it in itself will be the cause of systematically drifting of
> the mark, but rather varying a lot around that mark.
>
> Cheers,
> Magnus
>
>
> On 12/06/2014 08:16 PM, paul swed wrote:
>
>> All good answers with a good tube and enough current to read on the meter.
>> But I am working at the very limit of the Cs fumes. There is current,
>> about
>> .5 to 1 tick mark on the meter of a 5061 using a 5060 tube.
>> Thats the challenge on a very eol tube.
>> Regards
>> Paul.
>>
>> On Sat, Dec 6, 2014 at 1:56 PM, Magnus Danielson <
>> magnus at rubidium.dyndns.org
>>
>>> wrote:
>>>
>>
>>  Tom,
>>>
>>> On 12/06/2014 06:04 PM, Tom Van Baak wrote:
>>>
>>>  Paul,
>>>>
>>>> There are 7 peaks total, about 40 kHz apart (on my 5061A). If you're
>>>> talking about just the central peak, there are two smaller peaks on
>>>> either
>>>> side, about 1 kHz apart. The exact value depends on internal magnetic
>>>> field, which is specific to each beam tube design.
>>>>
>>>> For some measurements of all the peaks, have a look at:
>>>> http://leapsecond.com/pages/cspeak/
>>>>
>>>>
>>> These are the 7 Zeeman pedestals, and on top of them you have the Ramsay
>>> fringes. You can indeed lock onto the wrong Ramsey-fringe, but they too
>>> have amplitude differences. For a normal tube, they are quite
>>> significant,
>>> but if you look at the Ramsay fringes on the NIST-F1, they are much
>>> denser
>>> and looses amplitude much slower, so you need to pay more details of
>>> which
>>> fringe you use. The density of the Ramsay fringes is due to the
>>> observation
>>> time, which has been one of the driving forces to develop hydrogen masers
>>> and cesium fountains, but for a simple cesium tube, it's a few dm of
>>> distance and the average speed of the cesium steam.
>>>
>>>   You can play with the C-field in addition to playing with peaks:
>>>
>>>> http://leapsecond.com/images/cfield.gif  (578 x 4610 pixels)
>>>>
>>>>
>>> Which is a good illustration. It would be good.
>>>
>>>   For more details search the archives for the word Zeeman. For example:
>>>
>>>> https://www.febo.com/pipermail/time-nuts/2005-April/018171.html
>>>>
>>>> A nice description from hp how a cesium beam standard works:
>>>> http://leapsecond.com/museum/hp5062c/theory.htm
>>>>
>>>>
>>> Do check the FTS-4065C manual as I just uploaded. Good complementary
>>> information.
>>>
>>> Cheers,
>>> Magnus
>>>
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