[time-nuts] Re: HP Z3801A - Dead GPS Receiver - Oncore VP

[Bob kb8tq]

Hi

The 3081 takes a *long* time to get to it’s final “settled” state on it’s 
control loop. How long is a “that depends” sort of thing, but even for
short interruptions, it can be weeks. Cycling it puts you right back into
the start of the process. 

If you have a defective receiver, then replacing it sounds like the better
answer. 

Bob

> On Oct 12, 2021, at 11:10 AM, Björn <bg at lysator.liu.se> wrote:
> 
> Hi Bob,
> 
> Agree with others - is has been discussed here at the list that these ancient Oncore receivers have this issue. Not all of them, but some. This has nothing to do with the original use case and the systems was shifted out of cell tower applications a long time ago.
> 
> Kind regards 
> 
>      Björn 
> 
> Sent from my iPhone
> 
>> On 12 Oct 2021, at 16:58, Bob kb8tq <kb8tq at n1k.org> wrote:
>> 
>> Hi
>> 
>> I’m not suggesting that there is no issue. If this had been 
>> known to the original designers or users, routine shutdowns
>> and restarts would have been a show stopper. 
>> 
>> I’ve run 3801’s for years and years without ever power cycling
>> them. Other than power supply failure, they never had a 
>> problem. They did get detailed monitoring pretty much all 
>> the time. 
>> 
>> Bob
>> 
>>> On Oct 12, 2021, at 10:26 AM, CFO <tnut1 at sv16.org> wrote:
>>> 
>>>> On 12/10/2021 14.53, Bob kb8tq wrote:
>>>> Hi
>>>> 
>>>> You can be pretty sure that in their original installations
>>>> as a reference for a cell tower, shutting the whole thing
>>>> down every couple months was not part of the spec.
>>>> 
>>>> Bob
>>> I read over on the Z3801A site (forum) , that it seems like that GPS receiver oscillator would drift , wo. these shutdown/calibrate steps.
>>> That would make the receiver drift and be more and more insensitive over time , and eventually loose sync.
>>> 
>>> This oscillator is not to be confused with the HP DOCXO.
>>> 
>>> CFO
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