[time-nuts] Z3801A version issues - was Re: Substitute GPS in a Z3801A

[mike cook]

  would that have shown up in a firmware version id change?

try *IDN? and see if there is any correlation Matthew.



Le 30/08/2010 03:23, paul swed a écrit :
> I seem to remember a rollover about then that obsoleted older gps units.
>
> On Sun, Aug 29, 2010 at 5:40 PM, Matthew Kaufman<matthew at matthew.at>  wrote:
>
>>   I believe I've found a difference between the faulty units and the working
>> units... The faulty ones come up as 1/1/1997 when you do :SYSTEM:PRESET, the
>> good ones come up as 1/1/1998. Does this difference ring any bells for
>> anyone?
>>
>> Matthew Kaufman
>>
>> On 6/24/2010 8:41 AM, Matthew Kaufman wrote:
>>
>>> I now have *two* Z3801A units which misbehave in the following way (which
>>> this thread reminded me of):
>>>
>>> The GPS status says it acquires quite a few (5-6) satellites with high
>>> signal strength... then after a minute or two, for no apparent reason, it
>>> loses *all* of them simultaneously but immediately goes back into
>>> "acquiring" for the ones it was seeing, and a few seconds later, they're all
>>> back. During this time, survey (if in progress) is halted and then restarts
>>> and runs for a bit before halting again when it loses everything briefly
>>> again. Then, within days, the unit ends up out of lock... if I go check it,
>>> I see it doing the same thing, and when the satellites are being received it
>>> is in "fine frequency adjust" mode, but so far off the 1pps phase that it
>>> really has no hope of re-locking before the next time it drops and then
>>> reacquires all the satellites.
>>>
>>> This is independent of antenna, location, and 48v power source... one unit
>>> apparently has been this way since I got it, the other worked fine for
>>> months and then developed this problem.
>>>
>>> Without knowing more, I'm thinking it might simply be a bad GPS receiver
>>> board, thus the idea of trying to find a replacement, perhaps one that is
>>> better at staying acquired, has crossed my mind.
>>>
>>> Matthew Kaufman
>>>
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