[time-nuts] GPSDO recurring Time Interval aberation

Matt Osborn kc0ukk at msosborn.com
Sat Dec 20 20:40:02 UTC 2008


I've been tracking my Fury GPSDO (ROM version 1.21) equipped with an
Isotemp OXCXO134-10 oscillator for a couple of weeks now and have
noticed that the Time Interval (TI) spikes around 20 to 40 nsec
everyday at 17:45 UTC (11:45 AM CST local time). There are minor
spikes (5 nsec) every 2 to 3 hours, but I find the large spikes to be
very curious.

The oscillator itself has no idea of the time of day (does it?), the
Fury generated EFC follows the spike and brings the TI back into line
within tow or three minutes.  There are no unusual charges to the EFC
prior to or after the spike.

I've already tracked ambient temperature over several days and have
seen nothing unusual. I'm going to monitor line voltage next.

Has anyone else ever seen such behavior?

-- kc0ukk at msosborn dot com



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