[time-nuts] Re: Motorola UT Still Going

[Art Sepin]

HI Magnus,

The test method below was used to develop the ADEV graph. We haven't completely repopulated the Legacy products area under Support: https://synergy-gps.com/support/motorola-legacy-products/
but that area is being rebuilt as we have time.

Art

"Symmetricom 58530B Performance tests:
A series of tests were performed to determine if the various GPS modules have any effect on the overall performance of the 58503B. Data was collected using a 53100A Phase Noise Analyzer 10 times per second for a full day, resulting in 86,400 samples per test. The reference is an HP5065A Rubidium Frequency Standard running open loop, recently calibrated to GPS with a frequency accuracy of approximately 1e-12 at one second.
The data collected can be displayed in many ways. Shown below are the results of all tests displayed in Allen Deviation format, the most common way to show the frequency stability of an oscillator like the 58503B. On these plots, the lower the "noise", the better.

There is much that can be said about these plots regarding the internal crystal oscillator in the 58503B, its steering to GPS, and its averaging period. In this case we are primarily interested to see if the various 8-channel, 12-channel and 16-channel GPS receivers have any effect on the performance of the 58530B without changing any of its internal parameters.

The result suggests that all the GPS receivers perform well in the 58530B but the two 16-channel receivers, the Synergy SSR-6Tf+ mounted on the Goshay board and the Synergy SSR-VP/UT+ single board receiver perform better than any other GPS receiver."


-----Original Message-----
From: Magnus Danielson via time-nuts <time-nuts at lists.febo.com> 
Sent: Tuesday, March 5, 2024 6:11 AM
To: time-nuts at lists.febo.com
Cc: Magnus Danielson <magnus at rubidium.se>
Subject: [time-nuts] Re: Motorola UT Still Going

Hi Art,

Thanks for the plot. I think I have a few VPs around, and natually an M12+.

The "hill" around tau=1000s seems to be in the rough scale of a handfull of ns errors, which makes at least me think about sawtooth error, and what clock is used to generate PPS, dvs. compensation of sawtooth errors. If you could spread some light into what the numbers are it would be appreciated.

While things in general is improving is good, but it is also clear that oldest (VP - blue) is not worst.

I used to find datasheets for the Motorola GPS receiver chips. Do you happen to have that in your stash so you can share with us for historic reference?

Cheers,
Magnus

On 2024-03-05 06:58, Art Sepin via time-nuts wrote:
> That's good news, Gary. I recall that one of the UT+ firmware versions had the capability of operating past the 1024 week mark (but may have had bug fixes in a later version).
>
> How important one of the SSR replacement receivers becomes is application dependent. For many general timing applications, some SSR features may not matter but for updating legacy timing instrumentation, there are proven gains to be achieved over the original Motorola VP, UT+ and M12x receivers. Like better sensitivity means tracking more satellites at a given location;  accuracy of PPS ~ 21 ns for SSR vs. ~50 for UT+; anti-Jamming Performance in EMI Environments; no receiver 1024 Week Roll-Overs; four times faster TTFF than UT+ (not that important for always-on applications) and especially much better ADEV performance in legacy timing instruments.
>
> Apologize in advance for the unintended overt commercial tone of this response!
>
> Art
>
>
> -----Original Message-----
> From: Gary Myers <gary at geekslounge.com> On Behalf Of Gary Myers via 
> time-nuts
> Sent: Sunday, March 3, 2024 4:46 PM
> To: time-nuts at lists.febo.com
> Cc: Gary Myers <gary at geekslounge.com>
> Subject: [time-nuts] Motorola UT Still Going
>
> I got my Tac2/Motorola UT+ out of the closet and fired up Tac32 on my
> Win11 box. The UT is still going strong with no rollover and is currently on GPS Week 2304. I have a 16-channel Synergy SSR replacement but have seen no need to swap it in.
>
> Are there others out there still running their old rola's?
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