[time-nuts] "GPS once a day issues" ?
Hal Murray
hmurray at megapathdsl.net
Mon Oct 20 17:15:28 UTC 2014
kb8tq at n1k.org said:
> The combination of the constellation and the ionosphere are what I believe
> give you the once a day (rather than once per 12 hours) bump.
There is another layer. In addition to the "normal" once-a-day type
differences, the pattern of satellites drifts slowly from day to day. So
there is another pattern with a period of something like a month. If you
have a marginal setup, for example an indoor antenna, you can see things like
the holdover times drifting both in time-of-day when they happen and in
length of holdover as the satellite pattern at dawn/dusk changes.
Of course, at that level of detail, there are lots of other contributions
like rain that will also show up and may be more important.
--
These are my opinions. I hate spam.
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