[time-nuts] KS-24361 REF-0 standalone

Daniel Watson watsondaniel3 at gmail.com
Thu Oct 1 21:38:52 EDT 2015


Here's a little progress report on my REF-0 project. Though there hasn't
been a lot of activity in this thread recently, I do hope that some more
people have successfully gotten their REF-0s up and running.

My goal all along has been to retrofit a modern GPS into the REF-0. Over
the past couple of months I've designed a few small boards and gotten much
closer to a solution I'll be happy with. I first turned a prototype I
previously posted about into a PCB. That worked fine and installed in the
REF-0 without issues. Here is the write-up:


I also made a small breakout board for the U-blox NEO-6M GPS module in
order to test my layout. That worked extremely well, and allowed me to
proceed with a larger integrated design. You can find a post about that on
my blog if you are curious.

Recently, I finished the design of a complete GPS retrofit board. It is the
size of an Oncore GPS and mounts just like one in the REF-0. I am calling
it the Denuo GPS. All power and signalling goes through a header, so there
are no jumper wires internally or externally. The GPS module is the NEO-6M.
Combined with a small dongle I made for the interface connector, it creates
an almost plug-and-play solution for a GPS retrofit in the REF-0. You can
see a render of the board in the link below. I am looking forward to
getting those PCBs back and doing some testing.


I have a lot more to talk about, especially in regards to the choice of the
GPS module and timing features versus cost. I also have at least two other
board variations I am working on. One will be a step down in complexity,
essentially making the REF-0 a cleanup oscillator for Rubidium standards
and the like. There will also be a more advanced board with a higher grade
of GPS module and some really cool features to enable GPSDO
experimentation. But I will save all of that for another day and another

More to come.


Dan W.

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