[ntp:questions] Re: Good GPS for attic?

dold at XReXXGoodX.usenet.us.com dold at XReXXGoodX.usenet.us.com
Wed Feb 16 18:28:06 UTC 2005

In sci.geo.satellite-nav Gary S. <Idontwantspam at net> wrote:
> A friend who is a broadcast engineer for a local TV station had set up
> something like this for the station.

> It was a special GPS box designed for timesetting application, a 2U
> size rackmount, with a serious antenna on the roof. This was
> interfaced to supply the official station time throughout the studio
> building, the remote transmission facility, and their computer
> network. I think they usually display only to 1/100th of a second. 

That's downright humorous.
I slave my laptop to my local ISP with ntp, and never find that source to
be off by my visible correlation to other sources, like other ntp servers.
I have a GPS that I glance at, recognizing that the display isn't a high
priority, and might be off by a second or two.
I have a "weather station" that includes a WWV clock, synched nightly.
I have a DirecTV Tivo that gets it's clock from some unknown source, and
displays hh:mm:ss on the screen.
I used to have a Nextel phone with a "network adjusted" display time.
I watch the news on TV, with the clock display often in the bottom of the
screen.  Watching via DirecTV Tivo does cause a time lag between live TV,
and my viewing of it, so the "news" display is expected to be a tiny bit

The Nextel phone was consistently off by about four minutes, if I recall
correctly.  The time was the same on all of my coworkers Nextel phones as

I've seen the "news" display off by various amounts, anywhere from 15
seconds to several minutes.

The Tivo display is sometimes off by enough to affect the start time of
scheduled recordings.  Some rumor has it that the Tivo gets its clock from
the particular transponder being tuned, and that some of them, in turn, get
time from the station being uploaded, and in the case of local stations,
the times are not closely monitored.

With the internet, GPS, and ntp servers available, and the tight timing
necessary to keep distributed processing in synch, it seems silly that
anything driven by a computer isn't kept at least within a second or two of
real time.

Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5

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