[time-nuts] Hello from a new member

Tom Van Baak tvb at LeapSecond.com
Sat Feb 2 23:35:47 EST 2008


> * Two years ago I bult my own GPS frequency standard based on the design by
> James Miller but it has been a big disappointment. I started to suspect it
> was not reliable so I wrote a LabView program to compare it to the reference
> outputs of two ArgoSystems AS210 systems I found on eBay and restored. The
> LabView program confirmed my suspicions that the GPS receiver was briefly
> loosing its stability for brief periods several times a week. The AS210s
> tracked each other reliably and extremely closely. I have not gotten to the
> bottom of the problem with the GPS receiver yet.

Hi Dennis,

Welcome to the group.

Yes, that does sound like a GPS receiver board or even antenna
problem. I can loan you a working GPS 1PPS source if it would
help you debug.

My guess is it's not a problem with the James Miller design.
Which version are you using?. I tested one of his GPSDO
recently and was amazed at the performance. Remember
his designs are really *simple* (no microprocessor, no time
interval counter, no fancy DAC, no voltage reference), yet
the performance is quite amazing. See his latest:

http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm
http://www.jrmiller.demon.co.uk/projects/ministd/stab.htm

/tvb




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