X-GM-THRID: 1210064181903762437 X-Gmail-Labels: rsgb lf X-Gmail-Received: 60717f135089ef963174b2ce44d55b073c45c0f0 Delivered-To: daveyxm@gmail.com Received: by 10.64.250.6 with SMTP id x6cs308548qbh; Thu, 27 Jul 2006 07:01:13 -0700 (PDT) Received: by 10.49.93.13 with SMTP id v13mr25695nfl; Thu, 27 Jul 2006 07:01:12 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.gmail.com with ESMTP id m15si3376649nfc.2006.07.27.07.01.10; Thu, 27 Jul 2006 07:01:12 -0700 (PDT) Received-SPF: neutral (gmail.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1G66Lm-0003Sl-VJ for rs_out_1@blacksheep.org; Thu, 27 Jul 2006 14:56:30 +0100 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1G66Lm-0003Sc-6Q for rsgb_lf_group@blacksheep.org; Thu, 27 Jul 2006 14:56:30 +0100 Received: from smtpout10-04.prod.mesa1.secureserver.net ([64.202.165.238]) by relay2.thorcom.net with smtp (Exim 4.51) id 1G66Lg-0007dg-0u for rsgb_lf_group@blacksheep.org; Thu, 27 Jul 2006 14:56:30 +0100 Received: (qmail 32554 invoked from network); 27 Jul 2006 13:55:12 -0000 Received: from unknown (208.37.242.34) by smtpout10-04.prod.mesa1.secureserver.net (64.202.165.238) with ESMTP; 27 Jul 2006 13:55:12 -0000 Message-ID: <44C8C65B.4060706@w1tag.com> Date: Thu, 27 Jul 2006 09:57:47 -0400 From: John Andrews User-Agent: Thunderbird 1.5 (Windows/20051201) MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <000001c6b17e$4823a8d0$e6a4c593@RD40002> In-Reply-To: <000001c6b17e$4823a8d0$e6a4c593@RD40002> X-Spam-Score: -1.1 (-) X-Spam-Report: autolearn=disabled,AWL=-1.137 Subject: Re: LF: Tapped loading coil design spreadsheet Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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 Status: O X-Status: X-Keywords: X-UID: 4871 Jim, I have always viewed tapped loading coils as a high-pass "L" network, where the upper part of the coil leaves a small amount of capacitive reactance, representing the "C" in the network. The shunt inductor is the part of the coil below the tap. The issue is then to design the coil for the inductances above and below the tap. In the couple of these calcs I have done, I had accurate R+jX readings of the antenna in advance. That may be more difficult for amateur work. John Andrews, W1TAG