Return-Path: Received: (qmail 62984 invoked from network); 19 Jan 2004 16:28:18 -0000 Received: from unknown (HELO ptb-mxscan01.plus.net) (212.159.14.235) by ptb-mailstore02.plus.net with SMTP; 19 Jan 2004 16:28:18 -0000 Received: (qmail 32456 invoked from network); 19 Jan 2004 16:28:18 -0000 Content-Transfer-Encoding: 8bit X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 X-Priority: 3 X-MSMail-Priority: Normal Received: from ptb-mxcore01.plus.net (212.159.14.215) by ptb-mxscan01.plus.net with SMTP; 19 Jan 2004 16:28:15 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim) id 1AicG6-00087P-TU for dave@picks.force9.co.uk; Mon, 19 Jan 2004 16:28:14 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AicFl-0006d2-92 for rs_out@blacksheep.org; Mon, 19 Jan 2004 16:27:53 +0000 Received: from [134.58.240.45] (helo=thumbler.kulnet.kuleuven.ac.be) by post.thorcom.com with esmtp (Exim 4.14) id 1AicFk-0006cl-NL for rsgb_lf_group@blacksheep.org; Mon, 19 Jan 2004 16:27:52 +0000 Received: from localhost (localhost [127.0.0.1]) by thumbler.kulnet.kuleuven.ac.be (Postfix) with ESMTP id 701C41379F5 for ; Mon, 19 Jan 2004 17:27:22 +0100 (CET) Received: from antonius.kulnet.kuleuven.ac.be (antonius.kulnet.kuleuven.ac.be [134.58.240.73]) by thumbler.kulnet.kuleuven.ac.be (Postfix) with ESMTP id E9D67137BEC for ; Mon, 19 Jan 2004 17:27:21 +0100 (CET) X-Fake-Domain: dell-rik.fys.kuleuven.ac.be Received: from dell-rik.fys.kuleuven.ac.be (pc-10-33-165-177.fys.kuleuven.ac.be [10.33.165.177]) by antonius.kulnet.kuleuven.ac.be (Postfix) with ESMTP id C27594C2C5 for ; Mon, 19 Jan 2004 17:27:21 +0100 (CET) Message-ID: <5.1.0.14.0.20040119170650.03792818@u0019445.kuleuven.be> X-Sender: u0019445@u0019445.kuleuven.be X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Mon, 19 Jan 2004 17:30:11 +0100 To: rsgb_lf_group@blacksheep.org From: "Rik Strobbe" In-reply-to: MIME-Version: 1.0 X-Virus-Scanned: by KULeuven Antivirus Cluster Subject: RE: LF: Test failed... Content-Type: text/plain; charset=us-ascii; format=flowed X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.60 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: rs_out@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-PN-SPAMFiltered: yes X-Spam-Rating: 1 So John (W1TAG) was right with his second guess. However it is interesting that the 135 m tower was used on 1097 kHz (273 m wavelength), so it acted as a lambda/2 monopole. Since such antenna is high impedance (typical 1200 Ohm) the decoupling impedances of the light cables should be high too (probably several up to 10 kOhm at 1097 kHz). If it is non resonant (inductance only) then it should be still over 1000 Ohm at 136 kHz. But if the decoupling is resonant the impedance at 136 kHz may be as less as a few Ohm. It is likely that all 4 lamps are fed through a single decoupler, if you have access to that you can try to replace it by a one that is suitable on 136kHz. 73, Rik ON7YD At 16:13 19/01/2004 +0100, you wrote: >Hi Rik and others... > >After I discuss this problems with Bob OK2BVG and we found the problem. The >tower itsefs is DC isolated, but...on the tower are 4 lihgts (2x in 70m and >2x in 135m) powered by 410m of twisted-pair cable. So, this is total 820m of >wire well cupled with the antenna. This antenna has been on air for about 20 >year on the frequency 1097kHz. The filters are designed for this frequency >and have a very low reactance on 136kHz. Any idea? > >73 de Rich OM2TW