X-GM-THRID: 1242324366224743977 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.78.172.11 with SMTP id u11cs372561hue; Wed, 18 Jul 2007 08:34:00 -0700 (PDT) Received: by 10.82.162.14 with SMTP id k14mr2311336bue.1184772840779; Wed, 18 Jul 2007 08:34:00 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id i3si1021882nfh.2007.07.18.08.33.55; Wed, 18 Jul 2007 08:34:00 -0700 (PDT) Received-SPF: neutral (google.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 1IBBOG-0000Fw-Fx for rs_out_1@blacksheep.org; Wed, 18 Jul 2007 16:24:36 +0100 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1IBBOG-0000Fn-27 for rsgb_lf_group@blacksheep.org; Wed, 18 Jul 2007 16:24:36 +0100 Received: from smtp801.mail.ird.yahoo.com ([217.146.188.61]) by relay2.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1IBBOC-0008Qh-4T for rsgb_lf_group@blacksheep.org; Wed, 18 Jul 2007 16:24:35 +0100 Received: (qmail 63925 invoked from network); 18 Jul 2007 15:24:26 -0000 Received: from unknown (HELO Dave) (dsergeant@btinternet.com@81.157.212.26 with login) by smtp801.mail.ird.yahoo.com with SMTP; 18 Jul 2007 15:24:26 -0000 X-YMail-OSG: v8Ye0kUVM1mNjllIUDntFN2.j7oCOCK7uQ.l89tLESPrnXdsZ79u6mVzMC8XQhmZ0GmK0ROh2SB1xk6A9Iak1wIHeVi9SYK_L8Qs1xvmFVVUcdXV From: "Dave Sergeant" To: rsgb_lf_group@blacksheep.org Date: Wed, 18 Jul 2007 16:24:24 +0100 MIME-Version: 1.0 Message-ID: <469E3EB8.16230.1A91941@dave.davesergeant.com> X-mailer: Pegasus Mail for Windows (4.41) Content-description: Mail message body X-Spam-Score: -0.2 (/) X-Spam-Report: autolearn=disabled,AWL=-0.217 Subject: LF: [500]Tx and antenna improvements Content-type: text/plain; charset=US-ASCII 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: 3208 I mentioned yesterday that after retuning my vertical I had a diabolical swr at the shack end. That turned out to be because the pa was going unstable when it saw a 50 ohm load!!! I have now done a few changes to the pa to hopefully get round this problem. The T50-61 toroid I had used for the pa output coupling transformer wasn't really up to the job and was getting hot. I have replaced that with a 26mm 3C85 toroid from my 136 stock and reconfigured it to be an isolating transformer which gets rid of a nasty series coupling capacitor. I have also done a couple of changes with the decoupling. My website has the updated circuit. It now seems to be stable and also putting out a bit more umpth. My antenna tuning exercise yesterday has certainly got it one frequency (maybe a little on the low side as it is 50 ohm resistive at 501kHz and rises to 67.8ohms slightly reactive at 504kHz). Excellent SWR! It obviously has worked as I have just had a (slightly scratchy) chat with G3UNT followed by a nice QSO with Mike G3KZU in Oxford. Brian has never heard me before! 73 Dave G3YMC http://www.davesergeant.com