[time-nuts] Re: SpectraCom SecureSync1200 Questions

[john.haine at haine-online.net]

You can download a PC app called u-center from u-blox support which speaks via the serial link to their modules.  In my experience with a genuine u-blox module it was easy to set up and gives great visibility and controllability of the device.  Maybe you could use it to check out the device you have.  (Full disclosure: I used to work for u-blox though not on their GNSS products.)

-----Original Message-----
From: Robert Krenicki via time-nuts <time-nuts at lists.febo.com> 
Sent: Thursday, September 26, 2024 7:05 PM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Cc: Robert Krenicki <robert.krenicki at gmail.com>
Subject: [time-nuts] Re: SpectraCom SecureSync1200 Questions

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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