Return-Path: Received: from rly-da03.mx.aol.com (rly-da03.mail.aol.com [172.19.129.77]) by air-da02.mail.aol.com (v121.4) with ESMTP id MAILINDA021-a5947d1a735dd; Fri, 07 Mar 2008 15:36:26 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-da03.mx.aol.com (v121.4) with ESMTP id MAILRELAYINDA031-a5947d1a735dd; Fri, 07 Mar 2008 15:36:07 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1JXjHr-0005XV-9H for rs_out_1@blacksheep.org; Fri, 07 Mar 2008 20:35:27 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1JXjHq-0005XM-Lr for rsgb_lf_group@blacksheep.org; Fri, 07 Mar 2008 20:35:26 +0000 Received: from pne-smtpout2-sn2.hy.skanova.net ([81.228.8.164]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1JXjHm-0002OU-Mt for rsgb_lf_group@blacksheep.org; Fri, 07 Mar 2008 20:35:26 +0000 Received: from [127.0.0.1] (81.232.131.201) by pne-smtpout2-sn2.hy.skanova.net (7.3.129) (authenticated as u33233109) id 47A02DB900CA3D6E for rsgb_lf_group@blacksheep.org; Fri, 7 Mar 2008 21:35:13 +0100 Message-ID: <47D1A6FF.1080803@telia.com> Date: Fri, 07 Mar 2008 21:35:11 +0100 From: "Johan H. Bodin" User-Agent: Thunderbird 2.0.0.12 (Windows/20080213) MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org X-Karma: 0: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: LF: Smaller DC feeding choke in class E amplifier 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 X-AOL-IP: 193.82.116.20 X-AOL-SCOLL-AUTHENTICATION: listenair ; SPF_helo : n X-AOL-SCOLL-AUTHENTICATION: listenair ; SPF_822_from : n X-Mailer: Unknown (No Version) LFers, the usual design equations for class E amplifiers assume that the DC feeding choke has a very large inductance in order to keep the DC current practically constant over the RF cycle. I am in the process of building (yet another) class E CW QRP transmitter and the need for an almost infinite inductance has annoyed me for quite a while. Somewhere between the solder smoke puffs, I did some googling and found this interesting paper: http://www.msm.ele.tue.nl/~dmilosev/ECCTD2005.pdf My current project is a small 80m TX but I think this information is applicable to LF as well. 73 Johan SM6LKM