jimlux@earthlink.net said:

How rough?

Yes.  Search for orphan mode.  I've never tried it.  Let e know if you can't
figure out how to make it work and I'll use that as an excuse to learn more.

That should work.  I haven't found a GPS with PPS for the beaglebone.  What
level of accuracy do you want?  If you only need 100 ms or so, then a normal
junk GPS (no PPS) on USB should work.

There is at least one GPS+PPS over USB.  The GPS breakout board plus FTDI USB
2.0 breakout with a few wires gives you PPS with improved accuracy.  (Not
great, just 8x better than PPS over old/slow USB.)  I got mine from Sparkfun.

That should work too.  I don't know much about the Mac environment.  If it's
running a normal-enough ntpd it is already a server and you don't have to do
anything.  If not, you will have to build/install your own and/or poke holes
in the firewall rules.

--
These are my opinions.  I hate spam.

Hal Murray hmurray@megapathdsl.net wrote on Thu, 30 Mar 2017
at 13:43:34 -0700 in 20170330204334.18A8D406063@ip-64-139-1-69.sjc.megapath.net:

It is worth noting that the ntpd that Apple ships is kind of bizarre,
and it does not actually adjust the clock on the Mac. (Instead it
writes to the drift file -- or at least it is supposed to -- and an
Apple process called "pacemaker(8)" readthe drift file and tries to
maintain the systme clock. In my experience (only through Yosemite --
10.10) this mechanism was horribly broken and did not maintain my
laptop's system clock in any useful way.)

This probably doesn't actually affect the intended use (as the goal is
to keep machines in sync, not to keep them accurate), but anyone who
messes with ntpd under OS X should be aware that it is "weird."

Building the stock ntpd under OS X works just fine, and I recommend that
for anyone who wants to tinker with ntp under OS X.

--jhawk@mit.edu
John Hawkinson

I guess it's time for me to finish up that NTP cape for the BeagleBone.
I'm using a Furuno GT-8736 ( http://www.furuno.com/en/
products/gnss-module/GT-8736 )

I built up a prototype about two years ago but... got married very shortly
after that and haven't played with it since.

Is there any interest in something like this?  As with past group buys, I
never charge a penny of profit and sell at cost.  I want to say the brand
new GT-8736 boards are $26 a pop (my cost) from the vendor.

Is there a better board from Furuno for timing applications?

-Bob
N3XKB

On Fri, Mar 31, 2017 at 1:03 AM, David J Taylor <
david-taylor@blueyonder.co.uk> wrote:

Hi

The 8736 is a very nice part. I think some sort of group buy would be a good idea.

Bob

Sent from my iPhone

I'm happy to run a group buy for just the 8736.    My last quote from the
vendor was just a bit under $27 each, and that does not come with the board
connector.  I picked these boards for compatibility with Motorola
footprint, but also because it doesn't insist on goofy 3.0 volt power and
logic levels for communication.  It's happy with and rated for 3.3 volts
which is desirable.

I'll start a new thread for a group buy with details once I get a fresh
quote from the vendor.

-Bob
N3XKB

On Fri, Mar 31, 2017 at 12:45 PM, Bob Camp kb8tq@n1k.org wrote: