[time-nuts] z3801 - holdover and recovery issue

Magnus Danielson magnus at rubidium.dyndns.org
Mon Jul 11 15:01:10 UTC 2011


Dear Ron,

On 07/11/2011 12:22 PM, Ron Hahn (EI2JP) wrote:
> Colleagues,
>
> My Z3801 has developed a peculiar problem over the last few weeks. Its
> been running for several years now (at three different QTHs) and has
> worked flawlessly until recently.
>
> The problem is that it seems to oscillate between "gps-lock" and
> "holdover". When I checked further it seems to be oscillating between,
> locked, recovery, and holdover, mostly staying in recovery and holdover.
>
> The gpscon status page is here -> http://www.ei2jp.org/gpscon/gpsstat.htm
>
> Having checked closer today, I noticed that the EFC is only today
> showing "err" in the health monitor. Suggestions on whan'ts gone wrong
> please?

You aren’t tracking satellites!

Looking at your history you flip between tracking 0 or 1 sats.

I would start looking at the signal strength issue. Are your antenna OK?
Do another GPS lockup nicely on the same signal?

The GPS receiver there eats power and delivers a PPS and some serial 
data to the rest of the GPS. If the GPS receiver isn't happy about the 
input signal, all the rest will be unhappy, so you will have to focus on 
proper GPS reception conditions first.

I've found that sloppy antenna mounting, sloppy done connector work on 
home-made cables etc. been part of my overall problem with signal 
quality to my rig.

So do start in that end of the world.

Best Regards,
Magnus



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