Joe, et al. I put some info at: http://leapsecond.com/pages/reyax/
Here's what you need to know about those Reyax GPS boards: 1) These are simple, well-made, low-cost, tiny GPS boards. Four models are available, based on three u-blox chips. The prices are $14 $16 $20 $27. 2) The 3 chips are u-blox MAX-7C, NEO-7N, NEO-M8N. See http://www.u-blox.com for chip info. Board documentation: http://www.reyax.com/Module/GPS/RYN25AI/RYN25AI.pdf http://www.reyax.com/Module/GPS/RY725AI/RY725AI.pdf http://www.reyax.com/Module/GPS/RY825AI/RY825AI.pdf 3) The 4 boards available: http://www.ebay.com/itm/171493874434 http://www.ebay.com/itm/181553452840 http://www.ebay.com/itm/181562403752 http://www.ebay.com/itm/181566850426 4) The only difference between the $14 RYN25AI and $16 RYN25DI is that RYN25DI adds a ±10 V RS232 transceiver. The other 3 boards have a typical "inverted" logic-level (3.3V) serial interface, suitable for uP or SBC or UART/USB interface chip. I have no affiliation with seller "reyax" but their boards seem a step above some of the other GPS stuff on eBay. In general I gravitate to low-cost GPS receiver breakout boards with serial I/O and clean 1PPS output. It's amazing how well these integrated antenna boards work: a truly "3-pin" timing solution: power, ground, 1PPS. Note these are not "timing receivers" in the sense of RINEX output or external clock input or position-hold with sawtooth correction. But for less demanding work, the ±20 ns level that many of these receivers offer more than enough. 5) You can also find similar boards from US sellers such as http://parallax.com/ , http://adafruit.com/ , http://sparkfun.com/ 6) All of this is grossly overkill for NTP (at the 1 ms or even 1 us level). But if some of you are pushing NTP to sub-microsecond limits, cheap GPS/1PPS receivers like this are of interest. For more details, including almost medical-grade photos of a GPS patch antenna, see: http://leapsecond.com/pages/reyax/ /tvb ----- Original Message ----- From: "Joseph Gray" <jg...@zianet.com> To: <brian.ing...@systematicsw.ab.ca>; "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Thursday, October 23, 2014 9:18 PM Subject: Re: [time-nuts] GPS for ntp > OK, I see source of the confusion. There is a difference of "one" character > in the two part numbers. The RYN25 has the older Ublox chipset. The RY725 > has the Neo-7N chipset. There is only a $6 difference in price. I think > I'll get a few to play with. > > Joe Gray > W5JG _______________________________________________ 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.
