X-GM-THRID: 1208237376863323554 X-Gmail-Labels: rsgb lf X-Gmail-Received: 2a6b29b0a40eae0a274c823e6f7a8475d7069190 Delivered-To: daveyxm@gmail.com Received: by 10.64.249.17 with SMTP id w17cs188688qbh; Fri, 7 Jul 2006 02:35:55 -0700 (PDT) Received: by 10.48.161.11 with SMTP id j11mr1211428nfe; Fri, 07 Jul 2006 02:35:54 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.gmail.com with ESMTP id b1si4697228nfe.2006.07.07.02.35.54; Fri, 07 Jul 2006 02:35:54 -0700 (PDT) Received-SPF: neutral (gmail.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Fymdx-0008OO-8N for rs_out_1@blacksheep.org; Fri, 07 Jul 2006 10:29:01 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Fymdw-0008OF-TG for rsgb_lf_group@blacksheep.org; Fri, 07 Jul 2006 10:29:00 +0100 Received: from cas-mta1-fe.casema.nl ([83.80.1.20] helo=mta-fe.casema.nl) by relay1.thorcom.net with esmtp (Exim 4.62) (envelope-from ) id 1Fymds-00050Y-Vc for rsgb_lf_group@blacksheep.org; Fri, 07 Jul 2006 10:29:00 +0100 Received: from s9z5i6.casema.nl (53556FEB.cable.casema.nl [83.85.111.235]) by mta-fe.casema.nl (Postfix) with ESMTP id 60509322859 for ; Fri, 7 Jul 2006 10:56:42 +0200 (CEST) Message-Id: <6.1.1.1.2.20060707110012.033236e0@pop3.casema.nl> X-Sender: dickrollema@casema.nl@pop3.casema.nl (Unverified) X-Mailer: QUALCOMM Windows Eudora Version 6.1.1.1 Date: Fri, 07 Jul 2006 11:01:39 +0200 To: rsgb_lf_group@blacksheep.org From: Dick Rollema Mime-Version: 1.0 X-Antivirus: avast! (VPS 0627-2, 06-07-2006), Outbound message X-Antivirus-Status: Clean X-Spam-Score: 1.0 (+) X-Spam-Report: autolearn=disabled,AWL=-1.307,DNS_FROM_RFC_ABUSE=0.374,DNS_FROM_RFC_POST=1.376,FORGED_RCVD_HELO=0.05,HTML_20_30=0.504,HTML_MESSAGE=0.001 Subject: LF: variometers Content-Type: multipart/alternative; boundary="=====================_6931879==.ALT" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE 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 Status: O X-Status: X-Keywords: X-UID: 5004 --=====================_6931879==.ALT Content-Type: text/plain; charset="us-ascii"; format=flowed To All from PA0SE A disadvantage of variometers is that although the inductance can be varied the loss resistance of the coils remains the same. That means that when adjusted near minimum inductance Q = X/r can become very low. In practice the effect is diluted by the earth resistance which in most cases is considerably larger than the coil resistances. 73, Dick, PA0SE --=====================_6931879==.ALT Content-Type: text/html; charset="us-ascii" To All from PA0SE

A disadvantage of variometers is that although the inductance can be varied the loss resistance of the coils remains the same. That means that when adjusted near minimum inductance  Q = X/r  can become very low. 
In practice  the effect is diluted by the earth resistance which in most cases is considerably larger than the coil resistances.

73, Dick, PA0SE

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