From toaster-owner@m2xenix.psg.com Fri Jun 25 12:51:42 1993 Received: from m2xenix.psg.com by fido.wps.com (5.67/9999.1) id AA03641; Fri, 25 Jun 93 12:51:29 -0700 Received: by m2xenix.psg.com (/\==/\ Smail3.1.25.1 #25.1) id ; Fri, 25 Jun 93 12:16 PDT Return-Path: Received: by m2xenix.psg.com (/\==/\ Smail3.1.25.1 #25.1) id ; Fri, 25 Jun 93 12:16 PDT Received: from kumr.lns.com by lll-winken.llnl.gov (4.1/LLNL-1.18); id AA17275; Fri, 25 Jun 93 12:15:37 PDT for toaster@psg.com Received: by kumr.lns.com (/\==/\ Smail3.1.25.1 #25.3) id ; Fri, 25 Jun 93 12:15 PDT Message-Id: From: pozar@kumr.lns.com (Tim Pozar) Subject: Re: digital microwave link: Lynx Radio To: starling@cap.gwu.edu (Michael Starling) Date: Fri, 25 Jun 1993 12:15:14 -0700 (PDT) Cc: adamfast@hardy.u.washington.edu, toaster@psg.com In-Reply-To: from "Michael Starling" at Jun 25, 93 09:30:17 am Content-Type: text Content-Length: 2137 Status: OR Michael Starling wrote: > There's a similar system designed for the 902-928 band aimed at the > broadcast market. Is claimed to have a maximum range of 30 miles. > It basically supports an "ISDN"-like channel: bi-directional 256 kb/s plus > 38 kb/s of ancillary data. Needs to run with horizontal polarization to > achieve sufficient isolation from the cellular users. The product: > "Airlink" - by a Company called Cylink. It's being distributed by lots of > folks: Harris/Allied; RE America; Potomac Digital (in MD). I've been told > both ends of the system with yagis would run about 8k. We're sked to get > one of these units for evaluation any day now. NPR will use it for "RPU" > (remote studio) work in the DC area if it holds up well in this RF > environment. Interested in anyone's experiences who might have gotten one > already. The higher speed Cylinks will not do 30 miles. More like 5 to 8 miles. The 64Kb/s link may do 30 miles with the wind on its back. One thing to note regarding these Part 15, 900MHz links... The way that the companies are pitching the configurations for long distances like over a couple of miles DO NOT meet Part 15 requirements. They are in fact illegal. Part 15 sez that the link must... * Have a Transmitter Power Out (TPO) of 1 or less watts. * Have a antenna gain of 6 db or less. If the gain is higher the TPO must be reduced by the same amount. * Use the full bandwith for the spread spectrum. Companies like Cylink will sell you a yagi or dish (paraflector or full) that has gain over 6db for the long haul links. This is the only way you can get the distance. I talked to a un-named, but very much the authority at the FCC that said this will be the next thing they start to crack down on. They are aware of the problem and I would imagine they see some good revenue producing tickets they can write for the operators of these links. Tim -- Internet: pozar@kumr.lns.com FidoNet: Tim Pozar @ 1:125/555 Snail: Tim Pozar / KKSF / 77 Maiden Lane / San Francisco CA 94108 / USA POTS: +1 415 788 2022 Radio: KC6GNJ / KAE6247