Shaun Merrigan's Information Pages

Tag: GPS Disciplined Clock

HP/Symmetricom Z3805A GPS Disciplined Oscillator

Posted by Shaun Merrigan in Tech, Time and Frequency. Comments Off on HP/Symmetricom Z3805A GPS Disciplined Oscillator

22nd November

I recently acquired two HP/Symmetricom Z3805A GPS Disciplined Oscillator receiver/clocks.  These units seem to have several different configurations both inside the box and of the box itself, but all appear to have:

Two 10Mhz outputs
Two 1PPS outputs
24v DC power requirement

Inside the box, I have seen reports of:

HP 10811 DOXCO (10Mhz)
Symmetricom  DOXCO (5Mhz with a doubler)
16 channel GPS receiver (newer builds)
6 channel GPS receiver (older builds)

The box itself can be Samsung rack mount or HP benchtop.   My particular units were older  Samsung rackmount builds, but do have the desirable HP 10811 DOXCO.   Both units had older 6 channel GPS receivers that exhibited the 1024 week GPS rollover bug.  (That is, they displayed a date that was 1024 weeks in the past due to nature of the 10 bit week counter used in the receiver.)  I simply swapped the GPS … Read More »

GPS Clock Data Reset

Posted by Shaun Merrigan in News, Tech. Comments Off on GPS Clock Data Reset

5th January

GPS Clock Data Reset: I rebuilt the equipment rack that holds my network gear, HPZ3801A GPS Disciplined Clocks and the Zotac micro PC’s that run the associated software. The result is that there have been several interruptions to the data stream which I upload and display here. So I reset the log files, and restarted the logging from zero. The good news is that all the critical equipment now has UPS backup, so in addition to delivering clean power to the devices, short interruptions in the mains will not cause the clocks to reset.