[time-nuts] Z3801A Problem

Ed Palmer ed_palmer at sasktel.net
Mon Nov 5 21:38:16 UTC 2012


I've had a Z3801A for about a year.  It's always had an issue where the 
number of satellites tracked will drop to zero for one or two readings 
and then jump right back where it was ( often at 5 or 6 satellites ).  
This often (but not always) affects the EFC and/or PPS and/or HUP.  My 
Tbolt is running on the same antenna via an HP58536A splitter with no 
problems.  I've changed cables and splitter ports with no improvement.  
I've also checked the  power supply voltages and the frequencies of the 
two crystals on the Z3801A board.  All are fine.

I assumed that the VP was flaky so I recently pulled it out for testing 
and found no problems.  I then tapped into the link between the VP and 
the Z3801A and found that the number of tracked satellites reported by 
the Z3801A is often less than the number reported by the VP.  
Specifically, I've seen the VP report 6 satellites tracked at the exact 
same second that the Z3801A is claiming that there are no (zero) 
satellites tracked.

Does anyone know if there are any hidden parameters that the Z3801A is 
using to decide if a satellite is acceptable?  I looked through the 
manual but I couldn't find anything.  Is there a command I'm missing?

Thanks,

Ed




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