Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: Notesfiles $Revision: 1.7.0.5 $; site trsvax Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!inuxc!pur-ee!uiucdcs!convex!trsvax!mikey From: mikey@trsvax Newsgroups: net.ham-radio Subject: Re: "PL" Message-ID: <52800061@trsvax> Date: Mon, 8-Jul-85 10:47:00 EDT Article-I.D.: trsvax.52800061 Posted: Mon Jul 8 10:47:00 1985 Date-Received: Fri, 12-Jul-85 00:21:06 EDT References: <86@biomed.UUCP> Lines: 22 Nf-ID: #R:biomed.UUCP:-8600:trsvax:52800061:000:879 Nf-From: trsvax!mikey Jul 8 09:47:00 1985 PL is used not just for security or access to a "private" repeater and/or functions, but also to prevent interference. On 10M repeaters, each area of the country has subtones that it is supposed to use for repeater access. This prevents skip from one area of the country from activating all the repeaters in another part of the country. It also can be used to prevent interference where repeater coverage covers more that one metro area, for example, New York to Boston. There are probably some sites that if PL was not used, keying up would probably bring up many machines in the area. As to decoding the PL on a receiver, Kenwood did something similar except they use ASCII transmission of your call sign in the TR2600 handi-talkie. As to the legality of PL, there really isn't a problem. It's not cryptic data and it conserves bandspace. mikey at trsvax KA5MJQ