[time-nuts] My latest Net4501 NTP Server
rk at timing-consultants.com
Sun Oct 31 08:42:41 UTC 2010
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Jason Rabel
Sent: 31 October 2010 12:09 AM
To: time-nuts at febo.com
Subject: [time-nuts] My latest Net4501 NTP Server
Just thought I would share a quick pic of my latest home built NTP server.
I'm proud of it, I don't care if you aren't... :P
It is about as simple as one can get... Net4501 w/ Motorola Oncore M12+T..
all direct wiring, no extra components really needed (except one diode).
The M12+T I got from fluke.l on ebay... Took a while getting here (~ 2
weeks) but well worth the wait.
I used a low-voltage drop diode to get the 3.3v to ~3.0v for the GPS power
(seemed easier than trying to find a 3V voltage regulator or building a huge
circuit with one of those adjustable models), the 5V goes to the antenna...
TX, RX, and PPS are wired direct.
Mine didn't have the second serial port RS232 converter, I manually wired
across the chip location to get the TX & RX pads.
I used a connector on the GPS so I could swap it out easier, after soldering
I put some liquid electrical tape to hold things in place. I got it from
mouser (they had a few types), but the part # I used is M50-3120545
Drilled the holes for the GPS on a friend's vertical mill.
Still haven't decided if I want to mess with clock crystal or not. Also not
sure if I want to wire up extra status LEDs for NTPns.
It's so clean inside that I don't want to mess it up with more wires and
components and such.
Running PHK's NTPns on FreeBSD 6.3 (and old image I made years ago, but it
still runs great).
NOTE: If you are planning on buying a M12+ on eBay, the model's from rbm3695
are NOT the timing models. In the part# P273T12N16, the "N" denotes
navigation, the timing models have a T there. I got one to play with while
waiting for the real timing one from fluke.l... They *do* have a PPS and you
probably can use it for NTP timing purposes, but you have to be careful
about the commands you send to it. I'm not 100% sure but either some TRAIM
or auto-survery command will disable the PPS... NTPns has commands
hard-coded so you would have to modify it before building an image... With
regular NTP if you turn TRAIM off in the config and set a mode where it uses
the position in the file then you still get the PPS... I need to get me a
3V-RS232 converter so I can interface it with a regular PC and tinker some
I now have SIX network time servers... and only four PCs on my network...
I would love to find some more Net4501's cheap... I have a net4511 that I
might try next... It only has one physical serial port but so much of the
layout is identical to the net4501 that I'm sure if I trace back far enough
I can find where that second serial port is hiding and solder on the TX & RX
wires... While I'm thinking about it I'm going to burn another image of
nanobsd and boot this up to see indeed the OS sees a second serial port.
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