Date: Tue, 06 Jan 1998 22:52:33 -0800 From: Amancio Hasty <hasty@rah.star-gate.com> To: Nate Williams <nate@mt.sri.com> Cc: Michael Hancock <michaelh@cet.co.jp>, FreeBSD Hackers <Hackers@FreeBSD.ORG> Subject: Re: GPS for xntpd Stratum 1 servers Message-ID: <199801070652.WAA00401@rah.star-gate.com> In-Reply-To: Your message of "Tue, 06 Jan 1998 20:57:35 MST." <199801070357.UAA29123@mt.sri.com>
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I don't think that you can use the Garmin units as an accurate time source since they don't output accurate timing info -- they do have accurate internal timing. The Motorola Oncore boards seems to be most accurate ones out there. Related to the Motorola Evaluation kit there is also the totally accurate clock project . If anyone is interested please check out: ftp://aleph.gsfc.nasa.gov/GPS/totally.accurate.clock It has all sorts of info and charts. Amancio > > >From the xntpd docs it looks like he is using a Garmin 25XL GPS device. > > http://www.garmin.com only shows Garmin 45XL. I wonder how much these > > things cost? Anyway, this apparently works now on FreeBSD. > > I have a Garmin 12XL, and it's about $250. If the cheaper unit is > accurate enough, then it should work since they all output the standard > NMEA CCGGA codes which contains the time-stamp. (I haven't looked at > the source code to see if that's the message format the code uses.) > > If that's too much, you can get a Garmin 12 for around $180 (Cabela's > Spring catalog) which has less 'features', but that's not important for > doign time-clocks, unless you *need* an external antenna which the 12 > doesn't support and the 12XL does. The antenna for the 12XL runs about > $90 according to Cabelas, and the power supply is $19.. > > > 2) Poul is playing around with the Motorolla UT Oncore Evaluation Kit. > > From what I gather, the "Evaluation Kit" is what you would actually end up > > using. The unit is housed in an aluminum casing and they provide the > > RS-232 cable and some control software that runs on a PC. This looks like > > a cheap way to get a pretty high quality device. A lot of devices out > > there require a Gadget box to interface to a PC, the Evaluation kit takes > > care of that for you. > > The Garmin certainly doesn't require any device, just a funky cable to > plug into the back of the unit that terminates in a standard db9 serial > cable. > > > > Nate >
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