Return-Path: Received: from mtain-df08.r1000.mx.aol.com (mtain-df08.r1000.mx.aol.com [172.29.64.220]) by air-di07.mail.aol.com (v129.4) with ESMTP id MAILINDI071-eace4c02b18f2f9; Sun, 30 May 2010 14:42:23 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-df08.r1000.mx.aol.com (Internet Inbound) with ESMTP id 52E803800010E; Sun, 30 May 2010 14:42:22 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OInS1-0000x7-FN for rs_out_1@blacksheep.org; Sun, 30 May 2010 19:41:33 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OInS1-0000wy-2p for rsgb_lf_group@blacksheep.org; Sun, 30 May 2010 19:41:33 +0100 Received: from out1.ip02ir2.opaltelecom.net ([62.24.128.238]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OInRz-0005o0-EX for rsgb_lf_group@blacksheep.org; Sun, 30 May 2010 19:41:33 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av0EAN5NAkxcEYrC/2dsb2JhbACPDAOPInG+XIUWBA X-IronPort-AV: E=Sophos;i="4.53,328,1272841200"; d="scan'208,217";a="324426048" Received: from unknown (HELO xphd97xgq27nyf) ([92.17.138.194]) by out1.ip02ir2.opaltelecom.net with SMTP; 30 May 2010 19:41:25 +0100 Message-ID: <002601cb0027$b4d31cd0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: "rsgb" Date: Sun, 30 May 2010 19:41:24 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: coils Content-Type: multipart/alternative; boundary="----=_NextPart_000_0023_01CB0030.16419CA0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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-global-disposition: G x-aol-sid: 3039ac1d40dc4c02b18e7cfd X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0023_01CB0030.16419CA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Old RTTY 88mH inductors might be suitable if you can find them. or an automible ignition coil. My approach is different. I prefer to engineer/design the tx/pa for 50= ohms, feed this rf to the base of the anternna. Resonate the antenna= to the desired frequency with a suitable series inductor then match= this to the 50 ohm feed. This way I can keep track of what is happening, otherwise there are to= o many variables. In the past on 137 and 500 kcs this has been my approach and it has be= en sure fire every time. Get the antenna as high as possible, throw ou= t a few insulated ground radials, and a couple of earth rods, nothing= elaborate is required and you should be in business. If I fire up on 9 kcs this will be my method. de mal/g3kev ------=_NextPart_000_0023_01CB0030.16419CA0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Old RTTY 88mH inductors might be suit= able if you=20 can find them.
or an automible ignition coil.=
My approach is different. I prefer to= =20 engineer/design the tx/pa for 50 ohms, feed this rf to the base of the= anternna.=20 Resonate the antenna to the desired frequency with a suitable series= inductor=20 then match this to the 50 ohm feed.
This way I can keep track of what is= happening,=20 otherwise there are too many variables.
In the past on 137 and 500 kcs this= has been my=20 approach and it has been sure fire every time. Get the antenna as high= as=20 possible, throw out a few insulated ground radials, and a couple of ea= rth rods,=20 nothing elaborate is required and you should be in business.
If I fire up on 9 kcs this will be my= =20 method.
 
de mal/g3kev
 
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