[time-nuts] Tuning a Trimble Thunderbolt

Bob Camp kb8tq at n1k.org
Tue Apr 21 07:23:18 EDT 2015


Hi

inevitably on these devices, there is a marketing brochure that hits the high points
in the specification. That information is public and intended to get “buzz” going on 
the product. Once an OEM gets serious about the product, (the TBolt is targeted
at OEM’s) a detailed specification gets written. It may be in the form of detailed 
specs or in the form of a test regime / service scenario the unit is expected to 
perform in. That document is rarely available to the public.

==========

How are you measuring the holdover performance? You mention that you have 
no counter and no other standards. 

Bob

> On Apr 21, 2015, at 4:23 AM, Pete Stephenson <pete at heypete.com> wrote:
> 
> On Tue, Apr 21, 2015 at 12:08 AM, Bob Camp <kb8tq at n1k.org> wrote:
>> Hi
>> 
>> Expecting that unit to meet holdover after only being locked for 12 hours is not
>> a reasonable thing.
> 
> So it would seem.
> 
> Perhaps I was being a bit optimistic for out-of-the-box performance:
> the brochure listed the holdover specs but said nothing about how long
> one needed to let it run before it was able to meet those specs. The
> user guide hinted at it when it said that a 24 hour training period
> was the minimum for good results (which I assumed to mean "will meet
> the published specs") but earlier tests after 24 hours of being locked
> to GPS didn't meet the spec either.
> 
> Obviously it needs more time to stabilize and train. Hopefully my
> daughter doesn't eat it in the interim.
> 
>> Let it run for a week. Let it lock up for at least 4 or 5 days and get a good survey
>> on the location. It should run < +/- 5ns one sigma with a good survey.
> 
> Will do. I'm doing the 48 hour survey now with LH.
> 
> Cheers!
> -Pete
> 
> -- 
> Pete Stephenson
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