[time-nuts] My latest Net4501 NTP Server

[Robert Darlington]

Hi Jason,

Nice work.  Clean install of the hardware, wish mine was as neat:

http://www.nerdhouse.org/projects/timeserver/

I have a ghost image for my CF card there with FreeBSD 7 (I think).  A
little old since I haven't looked at it in over a year, but it's there for
anybody to take to get a jump start.

I noticed my net4501 was a little flaky if plugged into the wall outlet.
The thing would lock up sometimes after 10 minutes, sometimes after 10
days.   It was much more stable if plugged into a UPS that I assume filtered
the output.

My GPS board is one I custom designed for another project.  Two serial
ports, one for NMEA and the other for Trimble's proprietary binary format.
This is a Trimble Lassen IQ module with two output ports on it.

Your motherboard looks just like mine but is missing a lot of parts.  Looks
like you have only one ethernet port vs 3 on mine, one transciever chip vs 3
on mine (I assume these are ethernet transciever chips), no card slot on the
right, etc.   Is this a standard offering from Soekris?

-Bob, N3XKB

On Sat, Oct 30, 2010 at 5:09 PM, Jason Rabel
<jason at extremeoverclocking.com>wrote:

> 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.
>
>
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