[time-nuts] GPS interference and history...
bownes
bownes at gmail.com
Sat Jun 11 04:13:00 UTC 2011
That small hemispherical antenna could also have been 900mhz. I have one here @ home that is a combined gps/900mhz antenna from an ambulance tracking system.
On Jun 10, 2011, at 22:01, Hal Murray <hmurray at megapathdsl.net> wrote:
>
> lists at rtty.us said:
>> There's an enormous amount of gear out there that gets timing off of GPS.
>
> That's an interesting claim. Does anybody have any data on the usage of GPS
> for timing?
>
> I assume there is one in every cell tower and one in every 911 call center.
> Are there other large categories of users?
>
> What would it cost to replace all of it? If you wanted to do something like
> that, what would "it" cover? How about people like us running old recycled
> gear? (Z3801A, ThunderBolt, ...)
>
>
> I think I saw one last week. It was on a river level measuring station on
> the Sacramento River. It was a small block building. There was an antenna
> pointing up into the sky. I assume there is a satellite up there. There was
> also a small (~3 inch dia) hemisphere antenna. I assume it was GPS. (They
> had power going into the building (no solar panels) so it should have been
> simple to get a phone line too.)
>
> I'm not sure why they need GPS at the recording house. They know where it is
> so timing is the only use I can think of. But they could also get that at
> the receiving end. Millisecond accuracy isn't helpful. Second level
> accuracy might be interesting if something breaks and you want to know when
> the wave got to downstream stations. The risetime is probably over a second.
>
>
> --
> These are my opinions, not necessarily my employer's. I hate spam.
>
>
>
>
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