Xref: utzoo sci.electronics:3093 sci.astro:2223 comp.dcom.modems:1974 comp.misc:2579 rec.ham-radio:5074 Path: utzoo!utgpu!water!watmath!clyde!att!mtunx!pacbell!ames!pasteur!ucbvax!decwrl!decvax!tektronix!gvgpsa!davew From: davew@gvgpsa.GVG.TEK.COM (David C. White) Newsgroups: sci.electronics,sci.astro,comp.dcom.modems,comp.misc,rec.ham-radio Subject: Re: N.B.S. Time Service Keywords: Time Ticks Message-ID: <918@gvgpsa.GVG.TEK.COM> Date: 8 Jun 88 05:32:57 GMT References: <455@trane.UUCP> <4691@watcgl.waterloo.edu> <585@otto.COM> <3335@phri.UUCP> Reply-To: davew@gvgpsa.GVG.TEK.COM (David C. White) Organization: Grass Valley Group, Grass Valley, CA Lines: 23 In article <3335@phri.UUCP> roy@phri.UUCP (Roy Smith) writes: > If I call Colorado from New York and get a land line, I'm going over >maybe 3-4000 miles of path (doesn't make much difference if it's copper >wire, microwave, or fiber; in reality it's probably a combination of all >three). For a 3000 mile path at 300,000 miles/second, that's a 10 msec >delay. > The kicker is that commsats are in geosynchronous orbit. If I >remember correctly that means an altitude of 23,000 miles, making the path >length twice that (uplink + downlink) or 46,000 miles. That's about 150 >msec. Did I miss something, or were some basic laws of nature changed when I wasn't looking? I think we have the classic apples and oranges comparison case here. What I think Roy meant was that the speed was 300,000 km/sec rather than miles/second. The rest of the conversion from miles to kilometers is left as an exercise for the student. -- Dave White Grass Valley Group, Inc. PHONE: +1 916.478.3052 P.O. Box 1114 Grass Valley, CA 95945 davew@gvgpsa.gvg.tek.com