[time-nuts] My latest Net4501 NTP Server

[Jason Rabel]

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

http://www.rabel.org/pics/Net4501-2.jpg

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 more...

I now have SIX network time servers... and only four PCs on my network... lol...

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.