Return-Path: Received: (qmail 45999 invoked from network); 14 Jan 2004 14:37:29 -0000 Received: from unknown (HELO ptb-mxscan03.plus.net) (212.159.14.237) by ptb-mailstore02.plus.net with SMTP; 14 Jan 2004 14:37:29 -0000 Received: (qmail 30279 invoked from network); 14 Jan 2004 14:37:29 -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-mxcore03.plus.net (212.159.14.217) by ptb-mxscan03.plus.net with SMTP; 14 Jan 2004 14:37:27 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore03.plus.net with esmtp (Exim) id 1Agm99-0007kD-D1 for dave@picks.force9.co.uk; Wed, 14 Jan 2004 14:37:27 +0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Agm8X-0004z0-GB for rs_out@blacksheep.org; Wed, 14 Jan 2004 14:36:49 +0000 Received: from [134.58.240.46] (helo=spoetnik.kulnet.kuleuven.ac.be) by post.thorcom.com with esmtp (Exim 4.14) id 1Agm8X-0004yl-0r for rsgb_lf_group@blacksheep.org; Wed, 14 Jan 2004 14:36:49 +0000 Received: from localhost (localhost [127.0.0.1]) by spoetnik.kulnet.kuleuven.ac.be (Postfix) with ESMTP id C852B342FB for ; Wed, 14 Jan 2004 15:36:18 +0100 (CET) Received: from lepidus.kulnet.kuleuven.ac.be (lepidus.kulnet.kuleuven.ac.be [134.58.240.72]) by spoetnik.kulnet.kuleuven.ac.be (Postfix) with ESMTP id 3DDD334228 for ; Wed, 14 Jan 2004 15:36:18 +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 lepidus.kulnet.kuleuven.ac.be (Postfix) with ESMTP id 1AF6A380152 for ; Wed, 14 Jan 2004 15:36:18 +0100 (CET) Message-ID: <5.1.0.14.0.20040114153159.0359fdd8@u0019445.kuleuven.be> X-Sender: u0019445@u0019445.kuleuven.be X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Wed, 14 Jan 2004 15:39:01 +0100 To: rsgb_lf_group@blacksheep.org From: "Rik Strobbe" In-reply-to: <001901c3daa4$8afc2d20$f89a8418@Peter> References: <000b01c3da88$611cf140$9f96883e@d6y6c7> MIME-Version: 1.0 X-Virus-Scanned: by KULeuven Antivirus Cluster Subject: Re: LF: lf andnoise and offshore. 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 Hi Peter, At open sea QRM (man made noise) levels are likely to be low (apart from what you generate on your vessel). So I wouldn't worry about QRM. But the main advantage of /MM operation is that the loss resistance (the main factor that determines antenna efficiency at LF) is extremely low By using the steel vessel as counterweight the loss can be less than a few Ohms, at land it is in the range of 30 ... 150 Ohm at 136 kHz. Your main problem might be to make a low loss loading coil, as the loss of a typical loading coil (on 136 kHz) is in the range of 5 to 20 Ohm. 73, Rik ON7YD At 14:44 14/01/2004 +0100, you wrote: >Hi all, > >I am 100% new to LF. >I lack any LF experience at all at the moment. >Nevertheless, I consider to take a chance on LF. > >Does it make sense when I try to start LF from my ship /MM ( steel >fishermen cutter ) instead of from my condo ? >Does sea again ( if any at all ? ) and low man made en evironment noise add >substantially to the LF performance ? >( Besides, on my vessel I could erect bigger aerials than at the home QTH ). > >Where could I find explanations on (possible ) sea gain on LF ? >Where could I find information on the ( LF ) noise levels offshore ? > >Thanks for your appreciated thoughts. > >Peter, PE1ECM