Return-Path: Received: (qmail 25086 invoked from network); 22 Mar 2000 18:18:26 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by grants.core.plus.net.uk with SMTP; 22 Mar 2000 18:18:26 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 12XpTr-0006b9-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 22 Mar 2000 18:03:43 +0000 Content-Transfer-Encoding: 8bit Received: from mail.cc.kuleuven.ac.be ([134.58.10.6]) by post.thorcom.com with esmtp (Exim 3.02 #1) id 12XpTq-0006b4-00 for rsgb_lf_group@blacksheep.org; Wed, 22 Mar 2000 18:03:42 +0000 Received: from LCBD15.fys.kuleuven.ac.be (LCBD15.fys.kuleuven.ac.be [134.58.80.15]) by mail.cc.kuleuven.ac.be (8.9.3/8.9.0) with SMTP id TAA127284 for ; Wed, 22 Mar 2000 19:03:30 +0100 X-Priority: 3 X-MSMail-Priority: Normal Message-ID: <3.0.1.16.20000322200018.2337b42e@mail.cc.kuleuven.ac.be> X-Sender: pb623250@mail.cc.kuleuven.ac.be X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Mailer: Windows Eudora Pro Version 3.0.1 (16) Date: Wed, 22 Mar 2000 20:00:18 To: rsgb_lf_group@blacksheep.org From: "Rik Strobbe" Subject: LF: Antenna switching 72/136kHz In-reply-to: <000c01bf7ea4$c69a4ac0$20d725c3@194.95.193.10.fen.baynet.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: In my previous mail I forgot to mention that 'parallel tuning' of the antenna will only work with a high-impedance RX input (FET-preamp). For 50 Ohm input series tuning can be used (an additional series capacitor between RX and loadingcoil). This capacitor can be short-circuited to switch from 136 to 72kHz. A simple low-voltage relais will do. Thanks to Jim (M0BMU) to point this out. 73, Rik ON7YD