[time-nuts] EFC info on Trimble 34310-T OXCO

[Dave M]

I found the parameters for the X72's 1PPS input.  The range of Tau is 5 - 
10,000 seconds, or about 2 hrs, 45 min.  at the longest setting.  It 
defaults to 400 seconds. However, mine doesn't have the firmware to enable 
the 1PPS input, so it really doesn't matter.
Out of curiosity, does anyone know of any Rb units that can be programmed to 
a 24 hr (or longer) Tau, either by EFC or 1PPS input?

Dave M


Bob Camp wrote:
> Hi
>
> It is not what is done in the Efratom Rb’s. Their pps input is set up
> to get things on frequency / on time quickly. The assumption is that
> you plug it into a pps to get it “right” and then take off on your
> mission. That takes them into the short (for a Rb) time constant
> region.
>
> Bob
>
> On Aug 24, 2014, at 5:56 PM, Brooke Clarke <brooke at pacific.net> wrote:
>
>> Hi Bob:
>>
>> I think that's what's done in the SRS PRS10
>> http://www.prc68.com/I/PRS10.shtml
>>
>> Have Fun,
>>
>> Brooke Clarke
>> http://www.PRC68.com
>> http://www.end2partygovernment.com/2012Issues.html
>> http://www.prc68.com/I/DietNutrition.html
>>
>> Bob Camp wrote:
>>> Hi
>>>
>>> If you lock an Rb to GPS, you need / want / should do it with a
>>> *very* long time constant. Numbers in the one day to several days
>>> range are commonly seen. If you lock it up with a tighter (shorter
>>> time constant) loop, it will just wander around as it follows the
>>> GPS input. That’s what would happen if you hook your Rb to your
>>> Trimble and turn on the disciplining on the Rb. It will
>>> significantly degrade the stability of the Rb.
>>>
>>> If you have a temperature stable environment (or create one) you
>>> can get some very good results with an (good) Rb locked to a (good)
>>> GPS via a proper long time constant setup. It’s not easy, but it
>>> can be done.
>>>
>>> Bob
>>>