[time-nuts] Trimble GPS board

Arthur Dent golgarfrincham at gmail.com
Sat Aug 22 18:25:04 EDT 2015

rbenward at verizon.net wrote: "See below, here is a 73090
OCXO (same as on some of those GPSDO boards) powered by +12V."

You are incorrect in your assumption that the link you have
supplied shows a 73090 OCXO powered by +12VDC. The BOARD is
indeed powered by 12VDC (or 15VDC if you read the listing)
but if you look at all the photos you will see a 3-terminal
regulator on the bottom of the pc board.

The Trimble GPSDO I'm supplying 6.3VDC to had a 5 volt regulator
that has a measured output of 5.00VDC and the supply pin on the
oscillator had that 5.00VDC on it, not the 6.3VDC from my supply.
A continuity check shows a direct connection from the regulator's
5 volt output directly to the oscillator's supply pin. Because
of the higher current drawn by the 5 volt oven, running the input
to the board at 12VDC and wasting all that power as heat would
not be wise. 6.3VDC makes me happy and they chose a LDO regulator
for a good reason.

The one error I did notice is I said the board locked after it
found satellites but that is incorrect. It does find satellites
quickly but takes about 10 minutes to lock and that is when the
10Mhz output is enabled. I did some of my checking around 1AM
and that is not a good time for clear thinking or writing.


More information about the time-nuts mailing list