Re: RE GB3SC# Frequency stability

Tony G4NBS

Maybe slightly OT but I was driving South from mid GM both Sat and Sun Afternoon/Evening and for a short period noticed my speed according to the GPS varying even though I was under cruise control on straight, clear roads at the time it happened. Can't say I'd ever noticed it do that before unless it lost signal under bridges, mountains etc which wasn't the case this time. Might be coincidence?
Tony NBS

-----Original Message-----
From: ukmicrowaves@... [mailto:ukmicrowaves@...]On Behalf Of Andy Talbot
Sent: 03 July 2013 11:08
To: ukmicrowaves@...
Subject: Re: RE [ukmicrowaves] GB3SC# Frequency stability


It happened early to mid evening by the look of things.   Was OK at 1300 UTC yesterday when I went out /P to check, but John was reporting it low in freq at 2000.  Ok again this morning.     The GPS constellation used to have periods when certain areas had poor coverage, and if that were coupled with poor antenna view or partial blockage, problems would occur.   Apparantly the period of the problem moves with sideral time, so it gets approximately four minutes later each day.
However, these days although the constallation has to be much the same as before, the GPS satellites Tx several dB more power and there are more of them in orbit, albeit duplicating each other, so should be less of a problem.

On 3 July 2013 10:54, DEHAYS Dominique <Dominique.DEHAYS@...> wrote:

Hi Andy ,

I'm interested to know at what time that signal loss occured . I've lost
my GPSlock signal as well , Hdop up to 13! I get this pb sometimes and I
don't know wether it is really an antenna problem or maybe some kind of
GPS jamming? All looks normal in the hardware so ???


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