Return-Path: Received: (qmail 80622 invoked from network); 10 May 2004 21:11:55 -0000 Received: from unknown (HELO ptb-mxscan01.plus.net) (212.159.14.235) by ptb-mailstore02.plus.net with SMTP; 10 May 2004 21:11:55 -0000 Received: (qmail 66743 invoked from network); 10 May 2004 21:11:54 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from ptb-mxcore01.plus.net (212.159.14.215) by ptb-mxscan01.plus.net with SMTP; 10 May 2004 21:11:52 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim 4.30; FreeBSD) id 1BNI3z-000GJd-WD for dave@picks.force9.co.uk; Mon, 10 May 2004 21:11:52 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1BNI2f-0001dn-PJ for rs_out_1@blacksheep.org; Mon, 10 May 2004 22:10:29 +0100 Received: from [213.232.95.59] (helo=relay.salmark.net) by post.thorcom.com with esmtp (Exim 4.14) id 1BNI2f-0001de-36 for rsgb_lf_group@blacksheep.org; Mon, 10 May 2004 22:10:29 +0100 Received: from postbode02.zonnet.nl ([62.58.50.89]) by relay.salmark.net with esmtp (Exim 4.24) id 1BNOb4-0000vU-4C for rsgb_lf_group@blacksheep.org; Tue, 11 May 2004 05:10:26 +0100 Received: (qmail 30646 invoked by uid 10); 10 May 2004 20:56:09 -0000 Received: (vexira-qq 30435-3895498F invoked from network) 10 May 2004 22:56:04 +0200 X-Fake-Domain: unknown Received: from unknown (HELO ibm) ([62.59.190.222]) (envelope-sender ) by postbode02.zonnet.nl (qmail-ldap-1.03) with SMTP for < >; 10 May 2004 20:56:04 -0000 X-Bad-Message-ID: no DNS (ibm) Message-ID: <000f01c436cf$d3b681a0$2102000a@ibm> From: "Dick" To: rsgb_lf_group@blacksheep.org References: <001701c43602$1b335540$2102000a@ibm> <000601c43608$23aa0600$6507a8c0@Main> Date: Mon, 10 May 2004 22:29:23 +0200 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2615.200 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200 X-AntiVirus: checked by Vexira MailArmor (version: 2.0.1.16; VAE: 6.25.0.3; VDF: 6.25.0.57; host: postbode02.zonnet.nl) X-Spam-Score: 1.0 (+) X-Spam-Report: autolearn=no,FROM_ENDS_IN_NUMS=0.869,RCVD_IN_SORBS=0.1 Subject: LF: TX-ouput transformer problems--part 2 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.9 required=5.0 tests=FROM_ENDS_IN_NUMS 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-PN-SPAMFiltered: yes X-Spam-Rating: 2 Well, thanks all for your comments and tips. It helped me, and I got some ideas about what might be wrong. I soldered out the transformer, and did some measurements on it. Dispite all precautions I found that apperantly the 2 core halves didn't make an ideal contact. Pressing the two halves did gave a large difference in inductance......... To give you an idea, it changed from 70uH to over 130uH........ Now I have to find a creative way to put them under a continue pressure, also when temperature changes, and without making a short......... I think this is the main disadvantage of using these cores. Of course one clever guy can make an adjustable pressure system, allowing to 'tune' the coil........... I guess that the coil should be in resonance on 137kHz together with the 10nF drain capacitors, which means roughly somewhere around 126uH for each coil part....... Hope to find some time this week to do this......but busy..... 73 Dick, pa4vhf