[time-nuts] z3801 - holdover and recovery issue

Ron Hahn (EI2JP) ei2jp at dhco.org
Fri Jul 15 13:06:25 UTC 2011


On 7/11/2011 3:57 PM, Charles P. Steinmetz wrote:
> Ron wrote:
>
>> Colleagues,
>>
>> My Z3801 has developed a peculiar problem over the last few weeks.
>>
>> 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.
>
> Have you tried substituting another antenna and cable (even just a 
> short cable with the antenna indoors)?  This looks like what I'd 
> expect a 3801 to do if its antenna or antenna connection were 
> intermittent.  While you have it disconnected, check that the 3801 is 
> putting antenna power on the coax.
>
Hi Charles,

I disconnected the mushroom-style antenna and measured the voltage 
between the TNC centre pin and shield;  This was 5 volts.  Connection 
looked clean and unaffected by weather or moisture ingress.  Reattached 
the connector and screwed it on until it was tight, then rechecked 
gpscon.  Satellites are now being received.

So I can only deduce from this that the TNC male (cable end) to TNC 
female (mushroom antenna) is intermittent.  Don't understand why but it 
now looks like it is receiving 6 satellites and the 3801 is in 
"recovery" mode.

http://www.ei2jp.org/gpscon/gpsstat.htm

R





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