[time-nuts] Cesium C Field Set?

Tom Van Baak tvb at leapsecond.com
Thu Feb 10 21:19:36 EST 2005


Interesting plot. You'll have fun getting to the bottom of it.

I would say the 100 ns wandering you see is not GPS.
If that were the case it would be like saying your one
surplus FTS cesium is better than all the USNO clocks.

Now, there is wander in GPS due to a host of factors
but it's more like 10 ns for the plain receivers guys like
us use. Unlikely you'd see that with a FTS4060.

If you have a rubidium my recommendation is to run
a comparison between the Rb and Cs in parallel. Then
you can narrow down where those spikes are coming
from.

I would turn ION corrections on. Just this week I'm doing
a parallel run between two M12's; one with and one
without corrections. I'll let you know what I find.

/tvb

----- Original Message -----
From: "Brooke Clarke" <brooke at pacific.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Thursday, February 10, 2005 15:02
Subject: [time-nuts] Cesium C Field Set?


> Hi:
>
> Here's a plot of the time interval between a zero crossing of the 1 MHz
cesium output vs. an average of 1,000 GPS 1 PPS.  It's been going for over
10 days and I think the wanderings are due to using different satellites in
the GPS constellation.  Has anyone else plotted GPS vs. Cesium, i.e. are
these results reasonable?
> http://www.pacificsites.com/~brooke/pdf/sn1227_CF544.pdf
>
> I have the ionospheric correction turned off on the GPS receiver, should
it be on?
>
> Have Fun,
>
> Brooke Clarke, N6GCE
>
> --
> w/Java http://www.PRC68.com
> w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
> http://www.precisionclock.com







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