[time-nuts] time-nuts Digest, Vol 34, Issue 9

[Murray Greenman]

T&Fers,

Re the HP Z3815A, let me answer a few questions:

1. Most of the few Z3815A units I know about use the HP E1938A
oscillator, and that's what plugs into the connector that's clearly
visible on one of Bill's photos. At least one example has an adaptor
labelled Symmetricom, carrying a Milliren oscillator. The GPS module is
by Furuno, and speaks NMEA. The Z3815A speaks SCPI, a closely related
dialect to the Z3801A, and works fine with SATSTAT.

2. The backplane is not the problem you guys are imagining. You can
easily pick signals off it, since the socket is 2.54mm pitch in both
directions (ordinary PCB strip pins work fine). The 19.6608, 4.096 and
1.544MHz signals are available there in 'pseudo-ECL' form, although
little is known about other signals. The 10MHz signal is available from
three (unknown type) coax connections in the white block at the top end,
but the back of this connector is easily accessible with the back cover
off. The GPS antenna connects here as well.

3. Inside, there are easily discovered SMB connections with 1PPS, 10MHz
etc.

4. Power is applied to the backplane, but it's also easily applied
internally as there is a socket footprint on the board. It's easy to
extend this to a socket on the back panel. The unit requires 20 - 56V at
about 25W, and runs fairly warm without ventilation assistance.

And most important of all:

NO, THERE ISN'T A GREAT HORDE OF THESE THINGS AVAILABLE! The few that
have surfaced down here have been distributed locally. Don't expect them
to be offered on the open market.

73,
Murray ZL1BPU