[time-nuts] Entry level system

Murray Greenman murray at rakon.co.nz
Thu Dec 13 20:31:43 EST 2007


I suggest that for anyone getting involved in frequency references for
the first time, and prepared to learn by doing things themselves, would
find it useful to have a go at building a simple GPS Disciplined
Reference.

Sure, they may not be the ultimate reference (especially if simple and
homebrew), but the results are better than references found in most home
workshops, and are a good inexpensive way to learn what is important.

There is a very simple SINGLE CHIP GPS Disciplined Reference design at
www.qsl.net/zl1bpu/MICRO/GPSCLOCK/ . While the design is presented as a
clock, it also disciplines a TCXO or OCXO reference and has good
graphical monitoring tools. While it works just fine (and at very low
power) using a V-TCXO, it will also operate with V-OCXOs, and there's a
version of the software which works with the HP 10811A and similar OCXOs
with negative sense control voltage.

With a bit of rummaging in the junk box, this unit can be built for $50
or less. You need a GPS receiver with 1pps, but you don't need a comms
receiver, oscilloscope, frequency counter or other fancy gear to set it
up.

Regards,

Murray ZL1BPU



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