Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dk05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 1763B380000B2; Sun, 13 Jan 2013 10:52:44 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TuPqd-0000VK-Dd for rs_out_1@blacksheep.org; Sun, 13 Jan 2013 15:51:47 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TuPqc-0000VB-W5 for rsgb_lf_group@blacksheep.org; Sun, 13 Jan 2013 15:51:46 +0000 Received: from mk-filter-1-a-1.mail.tiscali.co.uk ([212.74.100.52] helo=mk-filter-1-a-1.mail.uk.tiscali.com) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1TuPqb-0001R7-8H for rsgb_lf_group@blacksheep.org; Sun, 13 Jan 2013 15:51:45 +0000 X-Trace: 839009343/mk-filter-1.mail.uk.tiscali.com/B2C/$THROTTLED_DYNAMIC/b2c-CUSTOMER-DYNAMIC-IP/88.104.44.203/None/g4wgt@tiscali.co.uk X-SBRS: None X-RemoteIP: 88.104.44.203 X-IP-MAIL-FROM: g4wgt@tiscali.co.uk X-SMTP-AUTH: X-Originating-Country: GB/UNITED KINGDOM X-MUA: Microsoft Windows Mail 6.0.6002.18197Produced By Microsoft MimeOLE V6.1.7601.17609 X-IP-BHB: Once X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av8EACjX8lBYaCzL/2dsb2JhbABEvgMXc4IeAQEEAQgqAQUeKAYBBAUDAxEEAQEKJTMGFggGEwgJiAIKs1eOBYJIYQObY4pxgnU X-IronPort-AV: E=Sophos;i="4.84,464,1355097600"; d="scan'208";a="839009343" Received: from 88-104-44-203.dynamic.dsl.as9105.com (HELO GaryAsus) ([88.104.44.203]) by smtp.tiscali.co.uk with SMTP; 13 Jan 2013 15:51:23 +0000 Message-ID: From: "Gary - G4WGT" To: References: <50F1BC6E.9090405@iup.uni-heidelberg.de> <427C8E7C302341129739C903AAC04464@GaryAsus> <50F28C3F.3060405@xs4all.nl> <50F2D0A5.4070806@iup.uni-heidelberg.de> In-Reply-To: <50F2D0A5.4070806@iup.uni-heidelberg.de> Date: Sun, 13 Jan 2013 15:51:22 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18197 X-MimeOLE: Produced By Microsoft MimeOLE V6.1.7601.17609 X-Spam-Score: -0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hi Stefan, I have thought about LF & MF antenna coil switching but I am very wary about the very high voltages on the LF coil due to my short vertical antenna. At the moment I have 3 screw connectors to change over :- [...] Content analysis details: (-0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [212.74.100.52 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (g4wgt[at]tiscali.co.uk) -0.0 SPF_PASS SPF: sender matches SPF record -0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: c9d6a1e47761f7ec7375ac340bef30d0 Subject: Re: LF: Re: MF variometer Content-Type: text/plain; format=flowed; charset="ISO-8859-15"; reply-type=response Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.1 required=5.0 tests=MISSING_OUTLOOK_NAME 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-aol-global-disposition: G x-aol-sid: 3039ac1db40950f2d84c19eb X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hi Stefan, I have thought about LF & MF antenna coil switching but I am very wary about the very high voltages on the LF coil due to my short vertical antenna. At the moment I have 3 screw connectors to change over :- 1 - Main coil inductance 2 - Matching transformer input 3 - Matching transformer output I have also thought about using 4mm banana plugs to make the change over easier & quicker. But not sure about using banana plugs, are they suitable ? 73, Gary - G4WGT. ----- Original Message ----- From: "Stefan Schäfer" To: Sent: Sunday, January 13, 2013 3:20 PM Subject: Re: LF: Re: MF variometer > Hi Albert and Gary, > > Yes, here it is the same. The detuning due to wet soil is higher than on > LF. Also the relative rise of the resistive losses are higher than on LF. > It can make up to 3 dB here. > > Now i think about a switch that allows to switch from LF to MF remotely. > The idea is that the LF coil remains connected to the antenna (i.e. is not > switched), only the MF coil would be switched in parallel. There will be > some reactive current through the LF coil when operating on MF but it can > be compensated and the losses will be low. I still did no calculations. At > least the MF voltages and currents are quite low compared to LF... > > 73, Stefan/DK7FC > > Am 13.01.2013 11:28, schrieb Albert W: >> Hello Stefan es Gary, >> >> The same here depending on weather conditions and of course frequency >> change, using a relative small variometer (DC-motor adjustable from the >> shack) in series with the fixed L. >> >> 73, Albert PA0A >> >> >> >> >> >