Tom, There is an important error in your message below. The Motorola designed M12M receiver is still in popular and in full production mode. You can get them from Synergy Systems, LLC in San Diego. They are very friendly to time-nuts members. The M12M has been used continuously by commercial companies in the timing community since iLotus took over production from Motorola in 2006. The timing characteristics of the M12M are basically the same as the Motorola M12+ but the M12M has a wider input gain range (10 to 50 dB) and a faster Time To First Fix (TTFF) and it continues to be available from stock.
Synergy also has the SSR-6T series of receivers that have a uBlox module but emulate the M12M commands and messages. These are plug in replacements for the M12M. The emulation is not total but has most of what you need from the M12M command set. These boards support some additional commands including one that puts the receiver in uBlox binary message mode at 9600 baud. These boards are very useful to those wanting the improved performance of the uBlox modules but do not want to rewrite all their application software. They are also useful for those migrating from the Motorola world to the uBlox world but don't want to do it all at once. Finally, Synergy has the SSR-6Tru which is a uBlox receiver on a PC board that is the same size as the M12M and plugs into an M12M slot but communicates only in uBlox's binary language at all baud rates supported by the uBlox module. Rick W2GPS -----Original Message----- From: Tom Van Baak [mailto:[email protected]] Sent: Sunday, April 27, 2014 9:45 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] New timing receivers? For a nice comparison of the M12+T, M12M, and ublox-6T, start with page 34, and especially note the ADEV plot on page 40: http://www.cnssys.com/files/tow-time2013.pdf The ublox-6T performs at least as well as the M12+T does. They are both in the 1 to 2 ns/day ballpark. The advantage is that the 6T is a production part and the M12+T and M12M are no longer made. So that's why commercial users have been forced away from the Motorola or iLotus parts. But amateurs still grab any M12 they can find because they are so good, and now dirt cheap on the surplus market. Note that Rick Hambly created the (Synergy) SSR-6T, which is a ublox-6T on a M12+T compatible PCB. Using a PIC it transparently translates between motorola and ublox binary so that the board is h/w and s/w compatible with any M12+T; a drop-in replacement. The plots you see in that PDF are the result of comparing M12+T and ublox-6T for this project. See also: http://www.gpstime.com/files/PTTI/Low_cost_GPS-based_time_and_frequency_prod ucts.pdf The bottom line is if you're looking for a low-budget but very high-performance GPS timing receiver, the M12+T is still a favorite among amateurs. If you're looking for something more modern, or a GPS timing receiver to use in quantity, or want an architecture that does or will accommodate Galileo and GLONASS, and are willing to pay the higher price, then check out the ublox-6T. /tvb _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
