[time-nuts] Re: Please help. Motorola Oncore

Tue Sep 20 08:18:34 UTC 2022

Hi,

Not really. The format is the same. Subtle clarifications and use of 
flag fields is however.

One aviation GPS receiver crashed whenever the flag was set as a new 
satellite was introduced into the constellation. Considering the cost 
and effort involved of recertifying it after a bugfix, it became a 
hesitation to fix it. I think this was a learning experience to the air 
industry, so I think they now have means to address it on more regular 
basis, since I know that in more recent history the lack of timely 
update has been the reason for GPS receiver problems, not the lack of 
update as such. I will ask around on this.

It's the GPS III signals which will be very different, as it is packet 
based.

Cheers,
Magnus

On 2022-09-20 00:27, Bob kb8tq via time-nuts wrote:
> Hi
>
> It would not surprise me at all to find that a modern version of the
> almanac is different than the 1998 version. A lot has changed since
> then.
>
> Given that you can find these for < $10 on eBay. I would not invest
> a lot in them at this point â€¦. Once you get them running, you will
> have roll over issues.
>
> Bob
>
>> On Sep 19, 2022, at 4:36 PM, Marcelo Dantas <marcelo.f.dantas at gmail.com> wrote:
>>
>> Hi Bob,
>>
>> The modules are old. 1998/2000.
>>
>> I have left the UT+ running for about 36 Hrs. I have noticed that the battery on the UT+ is dead, so I am ordering a replacement.
>> However, while running powered for 36 hours I expected it would see "something". I wish there was a way to verify some of its internal information, to see if it was actually collecting something.
>>
>> The WinOncore software allows you to upload an almanac, and it talks about a .alm file extension, and on the .gov site I only found a latest_yuma.alm file, which I uploaded, but it would still show "bad almanac".
>> I have also tried to upload a .al3 (SEM) file, with the same result.
>> Both files seem to upload, so I am not sure which one should be the correct one, or if both are.   I am assuming the yuma because it has the .alm extension. (still a noob in this matter)
>>
>> On a new development, the GT+ started showing satellites, it shows 10 satellites visible, zero tracked.
>> The UT+ regardless of the almanacs uploaded, still shows zero visible, zero tracked.
>>
>> I am still trying to find a reference to the correct (expected) almanac file format and to the eventual calibration procedure referred previously.
>>
>> Thanks,
>> Marcelo.
>>
>>
>> On Mon, Sep 19, 2022 at 5:10 PM Bob kb8tq <kb8tq at n1k.org <mailto:kb8tq at n1k.org>> wrote:
>> Hi
>>
>> If itâ€™s showing â€œbad almanacâ€ then that is part of the issue.
>> It may not be *all* of the issue â€¦.
>>
>> How old are these modules? They went through several
>> revisions and each one was a big leap over the previous
>> version. If they date back far enough, it could take a very
>> long time to come up with an almanac.
>>
>> Bob
>>
>>> On Sep 19, 2022, at 3:41 PM, Marcelo Dantas <marcelo.f.dantas at gmail.com <mailto:marcelo.f.dantas at gmail.com>> wrote:
>>>
>>> @Bjorn: It is the same antenna which worked back then, it was sitting there in the same drawer. So, unless it degrades somehow over time, it should continue to work I guess.
>>> I have no idea though how to measure/verify if there's saturation going on.
>>> When I plugged this antenna to a U-Blox it immediately kicked in with a bunch of satellites in view, but the U-Blox might also have a different input impedance.
>>>
>>> @Bob "off for a while" means since mid 2018. So I immediately thought of an almanac, however I could not yet figure out the .alm file it would require.
>>> I have downloaded almanac files from the web, not oncore specific, but when importing them via WinOncore I do not get any success/failure messages, and the device continues to show "bad almanac"  on its status.
>>> I have a feeling that the issue is towards bad/outdated internal information. Or maybe the calibration John spoke about, if I can figure it out, could help.
>>>
>>> Thanks,
>>> Marcelo.
>>>
>>>
>>>
>>> On Mon, Sep 19, 2022 at 4:26 PM Bob kb8tq via time-nuts <time-nuts at lists.febo.com <mailto:time-nuts at lists.febo.com>> wrote:
>>> Hi
>>>
>>> The other gotcha depends a lot on just how long â€œoff for a whileâ€ is.
>>> If any of these devices are off power for decades, the internal data
>>> for the almanac ( = which sats are where ) will be way off.
>>>
>>> The process of random search is a lot faster with the newer modules.
>>> They have way more processing horsepower. Just how many hours
>>> (or days) it takes this or that example of an early module to come
>>> back to life â€¦. who knows â€¦.
>>>
>>> Bob
>>>
>>>> On Sep 19, 2022, at 2:14 PM, John Ackermann N8UR via time-nuts <time-nuts at lists.febo.com <mailto:time-nuts at lists.febo.com>> wrote:
>>>>
>>>> Some of the early Motorola receivers had an issue with long-term XO drift.  That can result in failure to lock if the unit has been powered off for a long time.  There is a procedure to recalibrate it (no test equipment required).  I think it was written up in a Motorola app note that's available on line, but I can't put my finger on it right now.
>>>>
>>>> John
>>>> -----
>>>>
>>>> On 9/19/22 07:53, Gregory Beat via time-nuts wrote:
>>>>> IF you start with Fixed Position mode, THEN this speeds up process.
>>>>> I would also suggest a CLEAR View of Sky for the Antenna.
>>>>> Motorola Oncore UT Plus Engineering Notes (circa 2000)
>>>>> https://synergy-gps.com/wp-content/uploads/2018/11/ut-engg-notes.pdf <https://synergy-gps.com/wp-content/uploads/2018/11/ut-engg-notes.pdf>
>>>>> Motorola Oncore GT Plus Engineering Notes (circa 2000)
>>>>> https://www.tapr.org/pdf/GT_Eng_Notes.pdf <https://www.tapr.org/pdf/GT_Eng_Notes.pdf>
>>>>> UT Plus model numbers:
>>>>> R5122U111x - right angle OSX
>>>>> R5222U111x - right angle OSX, on-board Lithium battery
>>>>> R5122U115x - straight OSX
>>>>> GT Plus model numbers:
>>>>> R3111G111x - standard version
>>>>> R3211G111x - on-board Lithium battery
>>>>> R3111G114x - SMB antenna connector
>>>>> greg, w9gb
>>>>> ==
>>>>> Date: Sun, 18 Sep 2022 08:42:18 -0400
>>>>> From: Marcelo Dantas <marcelo.f.dantas at gmail.com <mailto:marcelo.f.dantas at gmail.com>>
>>>>> Subject: [time-nuts] Thanks for adding me, and please help. Motorola Oncore
>>>>> To: time-nuts at lists.febo.com <mailto:time-nuts at lists.febo.com>
>>>>> Hi there Everyone,
>>>>> Thanks for accepting me to this list.
>>>>> I am in (dire) need of help here and maybe one of you is a Motorola Oncore
>>>>> user and could assist.
>>>>> I have a couple Motorola Oncore modules, which I use mounted to a
>>>>> "baseboard" for timing purposes.
>>>>> One is a R5222U1115 and the other a R3111G1112.
>>>>> They have been sitting in a drawer for some time. Being "some time" since
>>>>> the pre-pandemic era.
>>>>> Now I am trying to use them again but for whatever reason they won't lock
>>>>> to any satellites.
>>>>> The modules are starting up, sending 1pps and seem to be accepting commands
>>>>> correctly.
>>>>> I have also tested the baseboard (power, serial, etc) and the antenna.
>>>>> The antenna works well on a third (non-motorola) module.
>>>>> I have tried everything, left the modules there running for 24 hours.
>>>>> No joy. None of them will lock to any satellites.
>>>>> I have tried defaulting them using WinOncore, no change.
>>>>> I have also tried to find an almanac file to upload, hoping it would help,
>>>>> but couldn't find one with the required .alm file extension.
>>>>> At this point I do not know what to do anymore. I have a system (module,
>>>>> board, antenna, power, etc.) that should just work, and yet it refuses to.
>>>>> Maybe there's some special factory reset? Maybe there's some command I do
>>>>> not know about? Maybe other software than WinOncore with some extra
>>>>> debug options?
>>>>> Any guidance here would be deeply appreciated.
>>>>> Thanks a lot in advance,
>>>>> Marcelo.
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