[time-nuts] Ashtech Z-12-R Operation?
Magnus Danielson
magnus at rubidium.dyndns.org
Fri May 29 20:53:34 UTC 2009
bg at lysator.liu.se skrev:
> Brooke & Tom,
>
>>> Hi:
>>>
>>> I got an Ashtech Z-12-R that powers up and displays the start up screen,
>>> see:
>>> http://www.prc68.com/I/AshtechZ12.shtml
>>>
>>> But it does not progress or respond to button presses. Does someone
>>> have a pdf
>>> manual or know how to kick start one of these?
>> Brooke,
>>
>> My Z12-T requires an external 20 MHz reference clock; I'm not
>> familiar with your -R model but it too may require this. It's not
>> uncommon for high-end geodetic-grade timing receivers to rely
>> on an external clock (e.g., cesium or maser). The idea is that
>> all received GPS signals are referenced to a real external clock
>> instead of an internal or virtual gps clock, or something like that.
>>
>> So try that first. The quality of the 20 MHz is not important just
>> to see if it starts working. But clearly, to get good results, you'll
>> want to lock your 20 MHz to something atomic.
>>
>> When I got my Z12 I played a bit with how to get 20 MHz. See:
>> http://www.leapsecond.com/pages/20mhz/
>>
>> /tvb
>
> My Z12 does not eat 20MHz. (5MHz to 10MHz works IIRC)
It should be configurable in 1 to 21 MHz in what appears to be 10 kHz
steps. I'll will experiment with them.
I think the Z12T bypasses the PLL lock and just buffers up the incomming
20 MHz and feeds it to the ADCs and DSP.
I racked Z12 is probably just a Z12T, which would make sense.
> Outside of the timing community, I suspect rubidiums are more common
> external sources than CS/H-masers.
Ionsphere, diffrential GPS and position ref stations use everything from
OCXOs to hydrogen masers.
Cheers,
Magnus
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