[time-nuts] More GPS testing, KS-24361 quirk
Bob Camp
kb8tq at n1k.org
Thu Aug 27 23:49:06 UTC 2015
Hi
It would be really interesting to eventually dig up a spec on just what these two
boxes are supposed to do. There are far to many “interesting features” for them
all to have been un-intentional.
Bob
> On Aug 27, 2015, at 5:41 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
>
> More testing...
> I lost everything from roughly 12:00-24:00 UTC Tue and 10:00-20:00 UTC Wed
>
>
> I stumbled into an interesting quirk in the KS-24361.
>
> Short version:
> After it has been in holdover for 5 or 6 minutes, the GPS unit switches to
> tracking the non-GPS unit and says it isn't in holdover mode anymore.
>
> Long story:
> I have a program collecting statistics. It was plugged into the unit with
> the GPS, aka Secondary. A graph of holdover time didn't make sense.
>
> The response to ":ROSC:HOLD:DUR?" is something like 3.08000E+002,1 I think
> the 1 at the end says it's in holdover mode and the 308 is the number of
> seconds it has been in holdover. Graphing holdover shows the ramp I expect
> for 5 or 6 minutes. Then it drops out of holdover. It returns to holdover
> for a minute or two when I expect it to be recovering.
>
> Digging deeper, the status page switches from
>>> Holdover: GPS 1PPS invalid
> to:
>>> Recovery: fine freq adj [TI -50.0 ns] 1PPS TI -50.0 ns relative to Ext
> and then to
>>> Locked to Ext: stabilizing frequency TFOM 3 FFOM
> 1
>
> The other box, non-GPS, aka Primary, does stay in Holdover.
>
> --------
>
> -------------------------- Secondary Receiver Status
> --------------------------
> SYNCHRONIZATION ............................................. [ Outputs Valid
> ]
> SmartClock Mode ___________________________ Reference Outputs
> _______________
>>> Locked to Ext TFOM 3 FFOM
> 0
> Recovery 1PPS TI +50.0 ns relative to Ext
> Holdover HOLD THR 1.000 us
> Power-up Holdover Uncertainty
> ____________
> Predict 11.5 us/initial 24 hrs
>
> ACQUISITION ................................................ [ Ext 1PPS Valid
> ]
> Tracking: 0 ____ Not Tracking: 10 _______ Time
> ____________________________
> PRN El Az PRN El Az UTC 06:40:32 27 Aug
> 2015
> * 1 55 270 *31 64 90 GPS 1PPS Invalid: not tracking
> * 3 35 310 *32 72 352 ANT DLY 1.000 us
> * 4 52 216 Position
> ________________________
> *11 37 243 MODE Hold
> *14 23 56
> 22 17 114 LAT N 37:26:04.813
> *23 23 260 LON W 122:12:15.762
> 25 10 55 HGT +9.95 m
> (GPS)
> ELEV MASK 10 deg *attempting to track
> HEALTH MONITOR ......................................................... [ OK
> ]
> Self Test: OK Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv:
> OK
>
>
>
> --
> These are my opinions. I hate spam.
>
>
>
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