Return-Path: Received: (qmail 4291 invoked from network); 16 Apr 2003 07:51:12 -0000 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 16 Apr 2003 07:51:12 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 21638 invoked from network); 16 Apr 2003 07:51:14 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 16 Apr 2003 07:51:14 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.14) id 195hdO-0004Kg-0k for rsgb_lf_group-outgoing@blacksheep.org; Wed, 16 Apr 2003 08:47:10 +0100 Received: from [194.217.242.80] (helo=anchor-post-39.mail.demon.net) by post.thorcom.com with esmtp (Exim 4.14) id 195hdJ-0004KX-BD for rsgb_lf_group@blacksheep.org; Wed, 16 Apr 2003 08:47:05 +0100 Received: from telemetry.demon.co.uk ([194.222.19.114]) by anchor-post-39.mail.demon.net with esmtp (Exim 3.36 #2) id 195hdI-0001XV-0d for rsgb_lf_group@blacksheep.org; Wed, 16 Apr 2003 08:47:04 +0100 Message-ID: Date: Wed, 16 Apr 2003 07:45:07 +0100 To: rsgb_lf_group@blacksheep.org From: "Tom Boucher" In-reply-to: <001e01c30389$be512e20$97d2fc3e@ian> MIME-Version: 1.0 X-Mailer: Turnpike Version 3.03a Subject: LF: Who stole the amps? X-Spam-Status: No, hits=-3.3 required=5.0tests=IN_REP_TOversion=2.53 X-Spam-Checker-Version: SpamAssassin 2.53 (1.174.2.15-2003-03-30-exp) X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Ian A pretty obvious point really, but are you sure the output power of your amplifier is not varying due to impedance changes as you alter the grounding? i.e. A mismatch is causing output power to drop. I had some very strange effects when I used to tune for maximum current instead of matching to 50 ohms. Now I have a 50 ohm SWR bridge from the Tx LPF and this goes to a simple series loading variometer. Results are a lot more predictable and I haven't blown a FET in about 2 years! 73, Tom G3OLB