[ntp:questions] garmin 18x and linux

Chris Albertson albertson.chris at gmail.com
Tue Sep 6 22:02:38 UTC 2011

> Why don't the manufacturers provide the PPS signal to the serial port
> themselves? Is it meant to be NMEA only?

You are thinking that all GPS recievers are only used for NTP.   There
are many other uses of PPS that do not involve the serial port on a
PC.  In fact I'd guess that MOST GPS used for precision timing do not
send PPS to a computer.   A common use a PPS is to phase lock a local
oscillator to prevent it from drifting.

If cost is an issue there are even lower priced options then the one
from Sure Electronics.   Older Moterola UT+ receivers sell for $18.
These actually have better specs and the signals are all run out to a
10-pin header, no soldering.

If you have $100 you can get a "Thunderbolt" GPS which is ideal for
precision timing.

There are a wide range of products and you can find some that come
with USA based tech support and are "turn key".  Or you buy the $18
unit from China solder some parts together.  You can find anything you

Chris Albertson
Redondo Beach, California

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