Xref: utzoo sci.electronics:3056 sci.astro:2196 comp.dcom.modems:1941 comp.misc:2538 rec.ham-radio:5018
Path: utzoo!utgpu!water!watmath!clyde!bellcore!rutgers!cmcl2!phri!roy
From: roy@phri.UUCP (Roy Smith)
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: <3335@phri.UUCP>
Date: 7 Jun 88 00:37:44 GMT
References: <455@trane.UUCP> <4691@watcgl.waterloo.edu> <585@otto.COM>
Reply-To: roy@phri.UUCP (Roy Smith)
Organization: Public Health Research Inst. (NY, NY)
Lines: 19

glenn@otto.UUCP (Glenn Scott) writes:
>   In addition, the "speed of light delay" via satellite shouldn't be much
> different than the speed of light delay over a copper wire...

	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.
-- 
Roy Smith, System Administrator
Public Health Research Institute
455 First Avenue, New York, NY 10016
{allegra,philabs,cmcl2,rutgers}!phri!roy -or- phri!roy@uunet.uu.net