[time-nuts] SpectraCom SecureSync1200 Questions

[Robert Krenicki]

I have recently stumbled across a pair of SpectraCom SecureSync 1200 units
that I have been restoring.  One is a 1200-003 (AC powered, TCXO, GNSS),
and one is a 1200-233 (AC/DC powered, standard Rubidium, GNSS).

A touch of backgound: One had a dead CF card, but I was able to clone the
card from the other unit and updated both to the latest software.  The
1200-003 came equipped with a Trimble RES-SMT GG, which works correctly,
however the 1200-233 came with a Trimble Revolution-T which does detect the
antenna, but never sees any satellites.  I am obviously more interested in
using the unit with the Rubidium Oscillator, so I swapped the GNSS modules
around and the -223 unit is now working.

On to the questions:
1) I am seeing more instability on the Rubidium Oscillator than I
expected.  I am regularly seeing phase errors of ±100ns.  I have never
worked with a Rb clock before, but I would expect smaller errors than
that.  Is this normal?

2) I purchased a uBlox M8T GPS module off of eBay, as I know that the more
recently manufactured units use these and should be supported.  It showed
up this morning and I replaced the bad Revolution-T, but the system does
not seem to recognize it at all.  The uBlox module is in the exact same
form factor and dropped right in, but I do not know if it is incompatible
or if it is defective.  I am unsure on how to test the unit externally.
The carrier board says WD22UGRC, and according to a random thread on
u-blox's forum, it shares the same pinout as the Trimble units.

3) I intend to use the -233 unit as my primary timesource in my
homelab/shack.  I only have AC power connected to it, so it is constantly
complaining about a lack of DC input.  I have been trying to find a way to
disable this alarm which also translates to a red light on the front of the
unit.   Short of hooking up a 48v power supply, is there any way to get
around this?

I was hoping that someone amongst this group had some experience with these
units, or their NetClock 9400 series sister that might be able to shed some
light on this.  I appreciate any help!

Rob KB1IPB