[time-nuts] Cesium C Field Set?

[Brooke Clarke]

Hi Tom:

Doug suggested that I turn on the Ionospheric correction and when I did 
that I saw an immediate change of about 100 ns, so I think the wandering 
is that correction.  Since then (about 4 hours)  the peak to peak 
variation is about 25 ns.   It will be interesting to see your plot with 
and without corrections.

Have Fun,

Brooke

Tom Van Baak wrote:

>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
>>
>>    
>>
>
>  
>