[time-nuts] TruePosition GPSDO Holdover Issues

Chase Turner ke4qdl at gmail.com
Tue May 15 17:32:08 EDT 2018


On Tue, May 15, 2018 at 3:27 PM, Hal Murray <hmurray at megapathdsl.net> wrote:

>
> If you are far enough north, you are in the hole, but you can see the
> other
> side of the hole over the pole.
>
> It's not hard to make your own plots.  This is from 66 38' north.
>   http://users.megapathdsl.net/~hmurray/time-nuts/Arctic/Polar-A.png
>
> If anybody wants to play, I'll put the code on the web.
>
> There are several steps.  First is to collect the data.  I have a python
> script that grabs everything from a NMEA device and logs each line with a
> time stamp.  The GPS orbit period is 12 hours so you need 12 hours of data
> to
> see everything.  But there are 30 satellites, so a few hours will show the
> hole.
>
> The next step is to extract the data into a useful format.  That's another
> python script.  Then, just feed that to gunplot.
>

Hi Hal,

I'd like to see a copy of the code, please.

Thanks!

-- 
Chase Turner
W4TI
http://w4ti.com



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