[ntp:questions] ESR looking for good GPS clocks

Kasper Pedersen ntp at taur.dk
Fri Mar 9 08:41:35 UTC 2012

Terje Mathisen wrote:
> The more I look at this, the more I settle down on using Ethernet as the
> communication channel!
> Something like the Soekris board reduced to the size of a pack of cards,
> with a (timing) gps chip on a daughter card, and an Ethernet port for

You do not need an entire Linux/FreeBSD/* capable box to do this. The
device only needs to transmit, preferably multicast. This avoids having to
configure an address on the device.
I experimented with this some time ago:

I also measured the timing across a small business network:

You are looking at a half-credit-card sized board with a modjack, a
microcontroller, a GPS module, a SMA connector, and a mini/microusb for
power. For 100 units, looking what I paid last time I bought small volume
for the parts, usd50/unit is feasible.
Then, to sell them, CE/FCC testing needs to be done, and that is usually
is usd5-10k. Unless there's a loophole that can be used for bare boards.

/Kasper Pedersen

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