[time-nuts] GPS interference and history...
Mark Spencer
mspencer12345 at yahoo.ca
Sat Jun 11 02:19:49 UTC 2011
Some other users of gps timing that I have noted thru observation or have personal knowledge of:
Timing for telecom providers (I have seen loran used in the past, but this option is more or less gone in North America now.)
Timing for power companies
Timing for industrial process control
Timing and frequency control for long range high performance microwave radio links
Timing and frequency control for private mobile radio systems
Timing for computer systems
Sent from my iPad
On 2011-06-10, at 7:01 PM, 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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