[time-nuts] Z3805 hold-Over

Bob Camp lists at rtty.us
Sun Nov 11 20:46:27 UTC 2012


Hi

Most of mine get down to ridiculously low numbers after a few weeks to a few months on. How long seems to depend on how many years the unit has been off power. Any estimate under 500 ns is questionable with that hardware. The firmware seems to be quite happy reporting numbers well below that. 

Bob

On Nov 11, 2012, at 1:36 PM, Doug Parker <doug.parker at btinternet.com> wrote:

> 
>  
> 
> Hi,
> 
> I've got a Z3805 from one of the Chineese sources and had problems with the HP 11801 oscillator which came with it. Even after a couple of weeks  operartion it was moving vast EFC voltages with  the 'Holdover Uncertainty Predict'  reaching a lowest of 19uS.
> 
> So I tried the HP oscillator from my Z3801 in the Z3805 and the daily EFC change is back to a resonable level, but after 5 days of settling down, the 'Holdeover Uncertainy Predict' has only got down to 10uS.and is holding about that value.
> 
> Could some one please advise what figures they are getting. As there's something sticking in my mind that the whole system should be lower than 6.3uS after 3 days of locked operation. Or have I been dreaming.....
> 
> I have attached a JPG of my GPSCon graph, hope it helps
> 
> thanks & 73s
> Doug
> G4DZU
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