[OT] Splitting PPS?

Richard Laager rlaager at wiktel.com
Wed Nov 13 17:38:40 UTC 2019

This is a bit off-topic, but I'm hoping this list can help.

Context, to avoid the XY problem:

I'm working with a small, Canadian Internet exchange that offers an NTP
service. They originally had one CDMA and one NTP master clock NTP
server feeding (via NTP) 3x Ubuntu + NTP Classic servers facing the
world. This is in a data center. They have one GPS antenna mounted on
the roof.

CDMA service has finally be killed off in their area, so that's dead.
Their GPS master clock died. So at this point, they're just Internet
stratum 2 / 3.

The tentative plan is to upgrade/reinstall Ubuntu, switch to NTPsec, and
deploy NTS. That's all easy.

It'd be nice if we could also replace the dead GPS master clock with a
directly connected GPS receiver, so we get PPS into the server (e.g. via
a serial port). That would make them stratum 1. I recently did this on
my own with a ublox 6 evaluation kit that I picked up for cheap on eBay.
For this project, we could buy an equivalent current generation EVK-M8T
for $250 from e.g. Digi-Key.

My intended question:

Is there an easy way to split an RS232 level PPS (and optionally the
GPS's TX for gpsd) into three systems?


What is the most cost-effective way to create three stratum 1 servers?


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