X-GM-THRID: 1210402038697719081 X-Gmail-Labels: rsgb lf X-Gmail-Received: c96738dd00aa28a3dd263ea4a9eb0daedb14b4f3 Delivered-To: daveyxm@gmail.com Received: by 10.64.249.16 with SMTP id w16cs9128qbh; Mon, 31 Jul 2006 00:02:16 -0700 (PDT) Received: by 10.49.29.3 with SMTP id g3mr1723113nfj; Mon, 31 Jul 2006 00:02:16 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.gmail.com with ESMTP id o53si7228258nfa.2006.07.31.00.02.13; Mon, 31 Jul 2006 00:02:16 -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 1G7Rid-0003a8-JT for rs_out_1@blacksheep.org; Mon, 31 Jul 2006 07:57:39 +0100 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1G7Rid-0003Zz-5D for rsgb_lf_group@blacksheep.org; Mon, 31 Jul 2006 07:57:39 +0100 Received: from yk-mlwprd2.northwestel.ca ([198.235.201.13] helo=mail2.theedge.ca) by relay2.thorcom.net with esmtp (Exim 4.51) id 1G7RiX-00071X-VL for rsgb_lf_group@blacksheep.org; Mon, 31 Jul 2006 07:57:38 +0100 Received: from eagles (whthyt235-40.northwestel.net [207.189.235.40]) by mail2.theedge.ca (Spam Firewall) with SMTP id 1B633F8D7 for ; Mon, 31 Jul 2006 01:03:29 -0600 (MDT) Message-ID: <001301c6b46e$95b42050$6501a8c0@eagles> From: "J. Allen" To: "LF \(RSGB\)" Date: Mon, 31 Jul 2006 06:57:27 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 X-Virus-Scanned: by Barracuda Spam Firewall at theedge.ca X-Spam-Score: 0.1 (/) X-Spam-Report: autolearn=disabled,AWL=0.069,FORGED_RCVD_HELO=0.05 Subject: LF: Antenna or transmitter tuning Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original 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: 6405 Hello again Friends, The single FET amp which Steve lent me has been working fine, but if you remember, during tuning the antenna system would come up with some weird wave shapes. The amp uses an air core output coil. The antenna loading coil , its matching coil and both coils in the transmitter's Low Pass Filter are air core as well. So there is no iron in the working system. Remember that when the antenna was tuned, one suggestion was to place a matching transformer with TV Horizontal Ferrite core in the circuit. When that was done, the waveform on the scope turned to garbage. (high in odd order harmonics) Today, the two FET amp which Scott lent me was put on the air. It has a ferrite TV output core which I wound and even though it was placed at the exact length of coax from the antenna which Steve's amp had been, it 's output waveform is badly distorted. It is important that I run the station at the maximum allowed IERP for the sake of proving non-interference. On Scott's amp, the current and voltage waveforms are identical and in phase, the amp runs very stable at over 300 Watts input, but the waveforms look awful. I have decided to switch back to Steve's transmitter and revisit both the output of Scott's amp and the antenna system. I am considering winding a air core transformer for it, but am unconvinced doing so will solve the real problem. I have a scopematch, and scope, an rf source capable of 18 kHz and up. Any ideas on how to approach this waveform problem? J.