[time-nuts] HP 5061Cs reference question

paul swed paulswedb at gmail.com
Sat Dec 6 23:24:46 UTC 2014


Slow by 44 ns in 27 minutes.
-2.7 e-11
Regards
Paul

On Sat, Dec 6, 2014 at 5:24 PM, Magnus Danielson <magnus at rubidium.dyndns.org
> wrote:

> Yes, but what's the offset?
>
> Cheers,
> Magnus
>
>
> On 12/06/2014 10:12 PM, paul swed wrote:
>
>> 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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