[time-nuts] Motorola M12+ breakout board
Besides the Furuno GT-8036 breakout board, I just did a layout for a board that converts the pinouts of Motorola M12+ compatible receivers to a 0.1" 9-pin header that (mostly) matches the Adafruit Ultimate GPS. The Adafruit ENABLE pin is repurposed as a DGPS RTCM corrections input and the Adafurit +3.3VREG output pin is used to provide external antenna (5V) power... the board defaults to use the 3.3V VCC power input for the antenna power. Contact me off list if interested.___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Motorola M12+
I am wondering if this is a sustitute of the original oncore VP receiver for the Z3801 -Z3805. (E-pay 281161070304 ) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Motorola M12+
Strange item... it has an M12+ and a supporting board full of components. Protocol translation from 12-channel to 8-channel? The link to the PDF file returns a 404. On Fri, Nov 22, 2013 at 9:32 AM, Pascual Arbona Lopez p.arb...@securimar.com wrote: I am wondering if this is a sustitute of the original oncore VP receiver for the Z3801 -Z3805. (E-pay 281161070304 ) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Motorola M12+
That's not the original gps rx.. (281161070304) Careful what you get off yixun.. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Pascual Arbona Lopez Sent: Friday, 22 November 2013 7:33 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Motorola M12+ I am wondering if this is a sustitute of the original oncore VP receiver for the Z3801 -Z3805. (E-pay 281161070304 ) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Motorola M12+ or M12M questions
Hello, I have been asked a question from a friend and would like to hear what the time-nuts have to say about the M12+ and M12M GPS receivers. His questions were: 1) It would be great if you could outline the broad algorithm and bits of information that go into keeping the 1 pps aligned to UTC. I want to be able to can ensure that we're at least aware of all the subtle effects (such as illustrated in the next question). 2) along with the gps time signal, information is broadcast to relate gps time to utc. whenever there's a step change in these corrections (such as on midnight 31/12/2008), how does the unit react? 2.1) in particular, how quickly does the time code reflect the change, and is the 1pps affected in any way? Time-Nuts. Any help on these two questions would be appreciated Steve Jones ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Motorola M12+ or M12M questions
2) along with the gps time signal, information is broadcast to relate gps time to utc. whenever there's a step change in these corrections (such as on midnight 31/12/2008), how does the unit react? 2.1) in particular, how quickly does the time code reflect the change, and is the 1pps affected in any way? Check the data sheet on the unit. It probably has a section describing the leap second stuff. They happen infrequently enough that you can usually get the info by other means. I'm sure the next one will be announced here. GPS works on GPS time. The satellites tell you the offset to UTC. I expect that offset kicks over at the magic time, but I wouldn't be surprised by bugs. Somebody may have data from watching the last time we had one. (I was watching a NMEA unit. It inserted the leap second at midnight GPS time rather than midnight UTC.) The PPS is tied to GPS time. I don't expect any quirks from leap seconds. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Motorola M12+ or M12M questions
Hal Murray wrote: 2) along with the gps time signal, information is broadcast to relate gps time to utc. whenever there's a step change in these corrections (such as on midnight 31/12/2008), how does the unit react? 2.1) in particular, how quickly does the time code reflect the change, and is the 1pps affected in any way? Check the data sheet on the unit. It probably has a section describing the leap second stuff. It is rarely beyond slogan level, if even mentioned in the datasheets. The manual rarely says much useful on the subject either. It happends from time to time that receivers freezes on leap seconds only for the stupid reasons it was not tested by the vendor. A simple single sat GPS emulator would have helped to trigger the bug, which is sufficient for timing receivers and should work for position receivers too. They happen infrequently enough that you can usually get the info by other means. I'm sure the next one will be announced here. There won't be one next new years even, it just became official yesterday. That was expected. GPS works on GPS time. The satellites tell you the offset to UTC. I expect that offset kicks over at the magic time, but I wouldn't be surprised by bugs. Somebody may have data from watching the last time we had one. (I was watching a NMEA unit. It inserted the leap second at midnight GPS time rather than midnight UTC.) OUPS! The PPS is tied to GPS time. I don't expect any quirks from leap seconds. If only listening to PPS and don't care about the time associated with it, you are safe. GPS time or UTC time should work equally well. I think you should fetch the GPS ICD 200 document and read up on the details in the signal structure on how UTC is represented in relationship to the GPS signal. Then imagine all the bugs there can be. There are (at least) three interpretations of when leap-seconds may be inserted: 1) At the end of every month. 2) At the end of every quarter. 3) At the end of every half-year. GPS is operated under the assumption that case 3 holds. There exist equipment assuming that case 2 holds. The actual definition allows for case 1, making case 3 the primary preference and case 2 the secondary preference. Lovely mess, isn't it? Anyway, if I don't recall it incorrectly (OK lazy to check), the GPS signal actually indicate WHEN then upcomming leap second will occur. This reduces to a up-comming leap second flag out of the GPS OEM board which can trigger pre-maturely execution of leap-second algorithm on the timing receiver, as we have seen in the Z3801A for instance. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Motorola M12+ or M12M questions
Martyn Smith wrote: Hello, I have been asked a question from a friend and would like to hear what the time-nuts have to say about the M12+ and M12M GPS receivers. His questions were: 1) It would be great if you could outline the broad algorithm and bits of information that go into keeping the 1 pps aligned to UTC. I want to be able to can ensure that we're at least aware of all the subtle effects (such as illustrated in the next question). 2) along with the gps time signal, information is broadcast to relate gps time to utc. whenever there's a step change in these corrections (such as on midnight 31/12/2008), how does the unit react? 2.1) in particular, how quickly does the time code reflect the change, and is the 1pps affected in any way? Time-Nuts. Any help on these two questions would be appreciated Steve Jones Your friend should download the manual from the Synergy-GPS website. http://www.synergy-gps.com/ Page 114 of the M12+ Timing receiver manual says: LEAP SECOND STATUS MESSAGE (@@Bj) Applicability: M12+ Timing and Positioning Receivers This message polls the receiver for current leap second status information that has been decoded from the Navigation Data message received from the GPS satellites. The data sent back by the receiver provides specific date and time information pertaining to any future leap second addition or subtraction. Leap seconds are occasionally inserted in UTC and generally occur on midnight UTC June 30th or midnight UTC December 31st. The GPS control segment typically notifies GPS users of pending leap second insertions to UTC several weeks before the event. When a leap second is inserted, the time of day will show a value of '60' in the seconds field. When a leap second is removed, the date will roll over at 58 seconds. The 'current UTC offset' will be zero if the receiver is set up to run in GPS time mode instead of UTC. Default mode: Polled Legacy Compatibility: The @@Bj message was used in an identical manner in virtually all Motorola receivers. --- Graham == ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Motorola M12+ or M12M questions
In message: 4a533c36.1030...@rubidium.dyndns.org Magnus Danielson mag...@rubidium.dyndns.org writes: : There are (at least) three interpretations of when leap-seconds may be : inserted: : 1) At the end of every month. This is the ITU standard. It says that leap seconds can be inserted at the end of each month. Almost no gear allows this, and the gear that does doesn't always do it in a sane way. : 2) At the end of every quarter. This is also ITU standard. These are the secondary times. They have never been used. : 3) At the end of every half-year. These are the primary times. : GPS is operated under the assumption that case 3 holds. Why is this the case? The GPS data just tells you which week the next leap second will happen, as well as the last time a leap second happened. How is it the case that you can say that 3 holds? : There exist equipment assuming that case 2 holds. : The actual definition allows for case 1, making case 3 the primary : preference and case 2 the secondary preference. Yes. : Lovely mess, isn't it? Leap seconds are evil and must die. For such a simple thing, there's so much complication that getting leap seconds right can be rather hard. At least there's no leap second this December... : Anyway, if I don't recall it incorrectly (OK lazy to check), the GPS : signal actually indicate WHEN then upcomming leap second will occur. : This reduces to a up-comming leap second flag out of the GPS OEM board : which can trigger pre-maturely execution of leap-second algorithm on the : timing receiver, as we have seen in the Z3801A for instance. You are correct. There's an indication when the next leap second will happen. The Z3801A uses this to turn on a simple 'leap second pending' which causes a leap second to happen at the next leap second opportunity rather than at the week published. The GPS operators turn on next leap second about 4 or 5 months early, which triggers the bug. Warner ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Motorola M12+T - On board oscillator phase noise specand/or part number
Hi All, Has anyone been able to figure out the part number and/or measured the phase noise of the quartz oscillator on board the Motorola M12+T? This will be an interesting figure to see. Regards, Stephan. This is an ADEV+MDEV plot for the 100 Hz output of an M12+ in free-run mode (no gps lock). http://www.leapsecond.com/pages/m12-adev/m12-free.gif If you want more data let me know. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Motorola M12+T - On board oscillator phase noise spec and/or part number
The crystal on my M12+T is marked top to bottom: 32.768 KDS0530 I would imagine it is a custom device from KDS http://www.kds.info/index_en.htm On Tue, 23 Dec 2008 11:06:30 +0200, Stephan Sandenbergh step...@rrsg.ee.uct.ac.za wrote: Hi All, Has anyone been able to figure out the part number and/or measured the phase noise of the quartz oscillator on board the Motorola M12+T? -- kc0ukk at msosborn dot com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Motorola M12+T - On board oscillator phase noise spec and/or part number
Hi All, Has anyone been able to figure out the part number and/or measured the phase noise of the quartz oscillator on board the Motorola M12+T? This will be an interesting figure to see. Regards, Stephan. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
