[ntp:questions] Sure gps looses all sattelite fixes
David J Taylor
david-taylor at blueyonder.co.uk.invalid
Fri Feb 24 18:26:48 UTC 2012
"unruh" <unruh at invalid.ca> wrote in message
news:cmQ1r.3572$py5.2962 at newsfe09.iad...
> The graphs of the signal strengths at the edges of these dropouts is in
Could not access this page in Firefox.
> Is this a flaw in the Sure unit (NOte that the sure unit drops its PPS
> signal as soon as it does not a fix. Some units-- Garmin?-- keep sending
> out PPS based on the freerunning onboard clock for quite a while, as I
> understand it.
> Teh Sure does not, which may be an advantage or a disadvantage.
> (ntpd/chrony grab one of the other servers which produces
> discontinuities in time when the pps comes back)
> Is it evidence of some outside noise source (jamming?) , microwave tower
That's certainly a possibility. I would try to locate the antenna so that
it has a clear view of at least half the sky, preferably towards the
south. You may also notice seasonal effects with foliage blocking the
signal more in spring and summer.
Mine have a moderate view of the sky, being located indoors, but on the
top floor of a domestic residence. Both pucks are stuck (magnetically) on
top of a PC, which does form a ground plane, but may also be a source of
electrical noise! I haven't monitored as you have, but I suspect I see
the effects of a drop-out perhaps once a fortnight.
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