[time-nuts] Re: HP Z3801A project update

[Bob kb8tq]

Hi

If the unit has been off long enough ( could be decades ….. ) there is a lot
about the GPS system that it really has no way of knowing. It will have to 
grab a full almanac and the ephemeris data from whatever it might happen
to be able to download it from. Since the data rate on GPS is mind bogglingly 
slow (by today’s standards), it takes a long time to get this done. Toss in 
various burps and restarts in the process and hours can easily be involved.

Bob

> On Feb 24, 2022, at 11:19 AM, paul swed <paulswedb at gmail.com> wrote:
> 
> Ed these older units do indeed take hours to potentially sync. Powerup and
> let go for 24 hours if its been off a long time. Normally doesn't take
> anything like 24 hours. But if that much time goes by thats a really bad
> indicator.
> I actually add in the battery backup to the gps receivers. 2 X AA mounted
> externally for easy replacement. That really helps.
> Good luck.
> Paul
> WB8TSL
> 
> On Thu, Feb 24, 2022 at 12:41 AM Kit <kitscally at iprimus.com.au> wrote:
> 
>> Ed,
>> 
>> I don't have any first-hand knowledge with the Oncore, but with 'other'
>> GPSDO's that haven't been turned on for some time (weeks/months or longer)
>> or almost always from a significant change in (antenna) location, there
>> maybe a significant time lag before the (a) oscillator gets up to
>> temperature/frequency and (b) for the internal search algorithm to figure
>> out where any satellites are as the almanac in memory has either been
>> dumped
>> or the previous old QTH is used, hence all the satellite coordinates are
>> incorrect.
>> 
>> Try turning the kit off, wait 30 to 60 mins, power up again and see of it
>> acquires 'lock' somewhat quicker.
>> 
>> Kit
>> VK1LL
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