[time-nuts] Re: SpectraCom SecureSync1200 Questions

[Robert Krenicki]

I do realize that is normally the case, however SpectraCom switched to a
uBlox M8T for this platform some time ago.  This is from the release notes
for firmware v5.4.0:   "NetClock now supports u-blox LEA-M8T GNSS receiver
boards. Trimble receivers continue to be supported, as well."  The module
that I purchased does have a LEA-M8T on it.

Other than perhaps that the unit may be defective, I do wonder if it is an
incompatible firmware issue.  The release notes reference the 3.01 TIM 1.10
firmware, but there are a few newer firmwares from uBlox at this point.  It
may be just "too new" for it is know what to do with it.  I just stumbled
across a thread on eevblog about this module and the required firmware, so
I am going to go down that rabbit hole for the moment.

On Thu, Sep 26, 2024 at 1:32 PM Bob Camp via time-nuts <
time-nuts at lists.febo.com> wrote:

> Hi
>
> Each of these modules (GPS or GNSS) speaks its own “language”. Brand T
> does not talk the same way brand U talks. This may even change between
> generations. An older brand U may not have quite the same command set a
> newer brand U device does. Yes, there are basic commands that likely work
> on multiple devices. This stuff is “on top of that”.
>
> The MCU in the “gizmo” chats with the module to get things going. It then
> pulls information from the module to see that all is well. Inevitably this
> gets you into the custom side of communicating with the module.
>
> Bottom line: You need a module that speaks what the device expects it to
> speak.
>
> Bob
>
> > On Sep 26, 2024, at 12:04 PM, Robert Krenicki via time-nuts <
> time-nuts at lists.febo.com> wrote:
> >
> > 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
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