Accurate time without a network connection?

Arthur W. Neilson III art at
Wed Apr 23 18:54:24 PDT 2003

--On Wednesday, April 23, 2003 7:58 PM -0500 David Kelly said:
| On Wednesday 23 April 2003 02:30 pm, Arthur W. Neilson III wrote:
|> <>
| That is really cool!

Thanks!  I had fun building it.  The GPS card cost me $110 from I got a discount cause I'm a ham and the TAPR board
was $45 bucks.  Pretty cheap for such an accurate clock.

Be aware not all GPSes have the PPS output.  If you really want
super accurate clock you need the PPS output.  The Motorola has
it but the ordinary Garmin handheld does not.

| As for other fun things I have my GPS sitting in a window trying to get
| a lock. It actually holds a lock about half the time. So I'm starting
| to play with the NMEA clock driver in ntpd.

I bet your GPS is in 3D position mode.  If you can command the GPS
to run in 0 position mode you'll get that lock 24x7.  The UT+ uses
a proprietary binary (non-NMEA) protocol that most software supports.
The Motorola's are used by the military embeded in all sorts of gear
and is a high performance and sensitive piece of equipment.

I do have a Garmin handheld which I use for hiking and such.
I use a GPS mapping software from along with raster
images of the USGS topo quads for Hawaii.  Works real well for
setting waypoins on a map and planning hiking trips etc.

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