Return-Path: Received: from rly-dd07.mx.aol.com (rly-dd07.mail.aol.com [172.19.141.154]) by air-dd05.mail.aol.com (v121.4) with ESMTP id MAILINDD054-b8747d2b4a9f9; Sat, 08 Mar 2008 10:46:05 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-dd07.mx.aol.com (v121.4) with ESMTP id MAILRELAYINDD071-b8747d2b4a9f9; Sat, 08 Mar 2008 10:45:47 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1JY1EN-0007aN-Qo for rs_out_1@blacksheep.org; Sat, 08 Mar 2008 15:45:03 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1JY1EN-0007aE-Er for rsgb_lf_group@blacksheep.org; Sat, 08 Mar 2008 15:45:03 +0000 Received: from wmsmtp.opaltelecom.net ([62.24.128.253] helo=smtp.talktalk.net) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1JY1EK-0005PN-CZ for rsgb_lf_group@blacksheep.org; Sat, 08 Mar 2008 15:45:03 +0000 X-Path: TTSMTP Received: from unknown (HELO g3kev) ([78.148.206.52]) by smtp.talktalk.net with SMTP; 08 Mar 2008 15:37:34 +0000 Message-ID: <001501c88132$54d39740$0301a8c0@g3kev> From: "mal" To: "rsgb" Date: Sat, 8 Mar 2008 15:37:33 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Karma: 0: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: LF: E CHOKE Content-Type: text/plain; charset="iso-8859-1" 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 LF/MF In my 500 khz class E amp I use a 1.150mH choke and it works well. This is what was available in my junk box, and larger than the calculated value. It is better to err on the high side. After designing a class E pa to suit your requirements, voltage availability etc the fun begins setting it up correctly. I consulted N O Sokal/WA1HQC publication and was able to get mine spot on. Page 16 of his document shows the various waveforms for correct and incorrect alignment when using an oscilloscope. It is important to get it exactly right if you want your FETS to survive, otherwise the transient spikes will kill them eventually. Once set up correctly forget about waveform monitoring, except you make changes to matching and antenna loading. I check my waveform periodically but it never varies since I have made no alterations to the antenna matching system or antenna. My PA is designed to match 50 ohm loads. There is plenty of info available for building a class E amp, follow the instructions carefully and avoid SMOKE. 73 De Mal/G3KEV