@cs.utexas.edu:marcus@osf.osf.org (Mark Roman) (05/17/89)
I am trying to get some information on radio clocks, specifically the kind used to provide a reliable standard time for a LAN. I have been recommended to Precision Standard Time Inc. in Fremont, CA. They make a dandy clock called the Time Source, which is perfect for my needs. It's a radio receiver tuned to WWV in CO, which puts out serial data on an RS232 port. This data, as you might've guessed, is the decoded time according to the NBS. Now here's the rub: It seems that PSTI has disconnected their phones. Unfortunately, I don't know if they have simply moved, or if they are out of business. This, as you might imagine, makes it difficult for me to order equipment. Does anyone out there in netland have any information on PSTI or their distributors? If they have indeed gone belly up, does anyone have information on other vendors of similar products? Please forward this on to anyone with knowledge. Thanks in advance, mark roman
len@csd4.milw.wisc.edu (Leonard P Levine) (05/18/89)
>From article <telecom-v09i0168m05@vector.dallas.tx.us>, by @cs.utexas.edu: marcus@osf.osf.org (Mark Roman): > It's a radio receiver tuned to WWV in CO, which puts out serial data > on an RS232 port. > does anyone have > information on other vendors of similar products? Heathkit, (Zenith) makes what they call an Absolute Clock with just about the same standards. Try that. + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + | Leonard P. Levine e-mail len@evax.milw.wisc.edu | | Professor, Computer Science Office (414) 229-5170 | | University of Wisconsin-Milwaukee Home (414) 962-4719 | | Milwaukee, WI 53201 U.S.A. Modem (414) 962-6228 | + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
DOCUMENT%vtvm1.bitnet@eecs.nwu.edu (Gary Kendall) (05/19/89)
In a recent posting Mark Roman asked for sources of radio timekeepers (WWV signal variety). I remember that Heathkit used to sell a kit for a similar clock that would monitor WWV's data stream transmission to keep itself in sync with their atomic clock; I'm not sure if it has a data output or not. Find a Heathkit catalog or give 'em a call. --Gary Acknowledge-To: <DOCUMENT@VTVM1>
dts@cloud9.stratus.com (Daniel Senie) (05/19/89)
In article <telecom-v09i0168m05@vector.dallas.tx.us>, @cs.utexas.edu:marcus@ osf.osf.org (Mark Roman) writes: > > I am trying to get some information on radio clocks, specifically > the kind used to provide a reliable standard time for a LAN. Heathkit makes such a device. It outputs to RS232. The cost is around $300, I think. It is available both as a kit and assembled. -- Daniel Senie UUCP: harvard!ulowell!cloud9!dts Stratus Computer, Inc. ARPA: anvil!cloud9!dts@harvard.harvard.edu 55 Fairbanks Blvd. CSRV: 74176,1347 Marlboro, MA 01752 TEL.: 508 - 460 - 2686
vern@zebra.uucp (05/21/89)
In article <telecom-v09i0168m05@vector.dallas.tx.us>, @cs.utexas.edu:marcus@ osf.osf.org (Mark Roman) writes: > I am trying to get some information on radio clocks, specifically > the kind used to provide a reliable standard time for a LAN. I have been > recommended to Precision Standard Time Inc. in Fremont, CA. They make a > dandy clock called the Time Source, which is perfect for my needs. > It's a radio receiver tuned to WWV in CO, which puts out serial data > on an RS232 port. This data, as you might've guessed, is the decoded > time according to the NBS. Try calling the National Bureau of Standards at Boulder, CO. They have digital time available on 303-494-4774 at 300/1200 baud. Type an 'H' immediately after connecting for a blurb about the format and accuracy. The blurb tells how you can get the time to a couple of milli-seconds at your location. They calculate the round-trip propagation time and adjust their timing accordingly. Don't worry about excessive time charges, they disconnect after 50+- secs. so that your call will always be less tha one minute. This also makes the 8 or 10 lines available for more users. The 1200 baud message has more information such as Daylight Time change dates, Julian date etc. but the 300 baud is more accurate. (2-3 ms vs. 5-6 ms). Good Luck. Vernon C. Hoxie {ncar,nbires,boulder,isis}!scicom!zebra!vern 3975 W. 29th Ave. voice: 303-477-1780 Denver, Colo., 80212 uucp: 303-455-2670
wmartin@st-louis-emh2.army.mil (Will Martin -- AMXAL-RI) (05/22/89)
Several postings to the list have pointed the original inquirer to the Heathkit "Most Accurate Clock" as something that would fill his requirements for an off-the-air source for, as he put it, "reliable standard time for a LAN". [I just went to look this up so I could post the model and be sure I got the facts right, and it seems that my Heathkit catalog here at work has walked off the shelf... Grrr...] It may purport to provide that service, but I would like to point out that reviews of that clock that appeared on the Info-Hams list some years back really panned it. It was most definitely NOT "reliable". The main problem seemed to be that the shortwave-receiving section, which was supposed to automatically tune the best signal from WWV on 2.5, 5, 10, or 15 MHz (don't recall if it tuned 20 MHz) was not very good, and often lost all trackable signals on any frequency. When it did that, it was supposed to switch over to its internal clock and then sync back up when it could receive a trackable WWV signal again. Well, the internal clock was inaccurate! That seems incredible in these days of $5 drugstore watches that keep better time than the finest mechanical movements did a few decades ago, but it seemed to be the case. More than one owner of this clock reported that as a problem to the net. Maybe Heath has improved this model since that time, but I would be VERY wary of putting my trust in it, and slaving automated system-time-setters to this device. There are commercial firms that sell far-more-expensive versions of this sort of time standard, and you really so seem to get what you pay for in this area. The more expensive sets tune the VLF WWVB signals, not the shortwave, so as to avoid the vagaries of shortwave propagation. You might luck out and get a Heath model that works fine, or be skilled enough to tinker with it and tweak it to better performance, but, if you are spending your company's money and not your own, I would recommend going with a professional piece of equipment. As I recall, the bad reviews were not only on the net, but also Radio Canada International's SWL Digest program, which has monthly receiver reviews by Larry Magne, reported these problems also. Regards, Will Martin