Return-Path: Received: from rly-dg03.mx.aol.com (rly-dg03.mail.aol.com [172.19.151.87]) by air-dg07.mail.aol.com (v123.4) with ESMTP id MAILINDG073-5b149d4f6d7335; Thu, 02 Apr 2009 13:33:21 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-dg03.mx.aol.com (v123.4) with ESMTP id MAILRELAYINDG032-5b149d4f6d7335; Thu, 02 Apr 2009 13:33:13 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LpQmA-0002TV-D0 for rs_out_1@blacksheep.org; Thu, 02 Apr 2009 18:32:26 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LpQmA-0002TM-0v for rsgb_lf_group@blacksheep.org; Thu, 02 Apr 2009 18:32:26 +0100 Received: from ttsmtp-1.cpwnetworks.com ([62.24.128.242] helo=ttsmtp.cpwnetworks.com) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1LpQm7-0008Hn-4B for rsgb_lf_group@blacksheep.org; Thu, 02 Apr 2009 18:32:25 +0100 X-Path: TalkTalk-smtp X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Am0KAPeS1ElZ82YP/2dsb2JhbACCJi+BbochBsUDg3wG Received: from unknown (HELO mal769a60aa920) ([89.243.102.15]) by ttsmtp.cpwnetworks.com with SMTP; 02 Apr 2009 18:31:17 +0100 Message-ID: <00b901c9b3b8$d446bd90$0301a8c0@mal769a60aa920> From: "mal hamilton" To: "rsgb" Date: Thu, 2 Apr 2009 18:31:16 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Karma: unknown: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Ant wire matching Content-Type: multipart/alternative; boundary="----=_NextPart_000_00B6_01C9B3C1.35AE1170" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_30_40,HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-AOL-IP: 193.82.116.20 ------=_NextPart_000_00B6_01C9B3C1.35AE1170 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable An efficient method of matching a wire antenna to a 50 ohm tx is to use a si= ngle inductor in series with the antenna wire to earth. Calculate the appro= x inductance required, then tap the wire antenna down the coil for resonance= at the required freq, then tap the coax centre up from the earth end for lo= west SWR. Coax braid to earth.=20 For reasons already stated a variometer is not the best way, although conven= ient.=20 I have used this system both on 137 and 500 and find it efficient and simple= to implement. 73 mal/g3kev ------=_NextPart_000_00B6_01C9B3C1.35AE1170 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
An efficient method of matching a wire ante= nna to a=20 50 ohm tx is to use a single inductor in series with the antenna wire=20  to earth. Calculate the approx inductance required, then tap the wire=20 antenna down the coil for resonance at the required freq, then tap the coax=20 centre up from the earth end for lowest SWR.
Coax braid to earth.
For reasons already stated a variometer is=20= not the=20 best way, although convenient.
I have used this system both on 137 and 500= and=20 find it efficient and simple to implement.
73 mal/g3kev
 
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