Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site alice.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!alice!danny From: danny@alice.UUCP (Dan Kahn, K1DK) Newsgroups: net.ham-radio Subject: Re: Antenna Tuners on Receivers Message-ID: <2996@alice.UUCP> Date: Fri, 21-Sep-84 17:17:10 EDT Article-I.D.: alice.2996 Posted: Fri Sep 21 17:17:10 1984 Date-Received: Tue, 25-Sep-84 21:35:52 EDT References: <239@whuxl.UUCP> Organization: AT&T Bell Laboratories, Murray Hill Lines: 24 I've never seen much reason to use an antenna tuner on a rcvr on HF, so I read with interest the articles on the net advocating the practice. Two reasons have been given, neither of which I find convincing: 1. "It will increase your S meter reading by an S unit or two." But in the great majority of cases on HF, if you are having trouble copying a signal it is because it is weak WITH RESPECT TO an adjacent signal or atmospheric or power-line noise, NOT because of ABSOLUTE weakness. Better antenna tuning increases signal AND interference/noise alike. (And if you're NOT having trouble copying the signal, who cares about the extra S units?) 2. "The antenna tuner is another tuned circuit, hence more selectivity, which should be helpful given all the QRM on 40 and 20 meters." (Approx quote.) But when people talk about the "QRM on 40 and 20" they are talking about QRM on the SAME FREQ or within a couple of KHz of the desired signal. No antenna tuner is going to help with that. (If you have a kilowatt xmtr a few hundred yards away, operating a few hundred KHz away from the signal you're trying to copy, the extra tuned ckt could help, but that is clearly a special case.) Dan Kahn, K1DK Bell Communications Research Murray Hill, NJ