Return-Path: Received: (qmail 18345 invoked from network); 22 Apr 2002 18:23:14 -0000 Content-Transfer-Encoding: 8bit Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by exhibition.plus.net with SMTP; 22 Apr 2002 18:23:14 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 29565 invoked from network); 22 Apr 2002 17:31:53 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 22 Apr 2002 17:31:53 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16zj6N-0003Up-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 22 Apr 2002 20:03:51 +0100 Received: from hestia.herts.ac.uk ([147.197.200.9]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16zj6M-0003Uk-00 for rsgb_lf_group@blacksheep.org; Mon, 22 Apr 2002 20:03:50 +0100 Received: from gemini ([147.197.200.44] helo=gemini.herts.ac.uk) by hestia.herts.ac.uk with esmtp (Exim 3.22 #1) id 16zhZS-0000k6-00 for rsgb_lf_group@blacksheep.org; Mon, 22 Apr 2002 18:25:46 +0100 Received: from [147.197.232.252] (helo=rsch-15.herts.ac.uk) by gemini.herts.ac.uk with esmtp (Exim 3.33 #1) id 16zhZR-0004ig-00 for rsgb_lf_group@blacksheep.org; Mon, 22 Apr 2002 18:25:45 +0100 Message-ID: <5.1.0.14.0.20020422172434.00a89200@gemini.herts.ac.uk> X-Sender: mj9ar@gemini.herts.ac.uk X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Mon, 22 Apr 2002 18:15:53 +0100 To: rsgb_lf_group@blacksheep.org From: "James Moritz" Subject: RE: LF: Good capacitance/inductance meter... In-reply-to: References: <16z3F2-0asCcGC@fwd00.sul.t-online.com> 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: Dear LF Group, One needs to be slightly cautious about this type of measurement - the inductance meter measures at a frequency somewhere in the LF range which depends on the inductance being measured - in general, this frequency will not be the same as the intended operating frequency of the loop. The inductance of the loop is fairly frequency dependent due to distributed capacitance, skin and eddy current effects, so the value at the measuring frequency will not be exactly the same as at the operating frequency. This is likely to give only very small errors for moderately sized, single turn LF loops, but could be serious for multi-turn loops with high inductance and stray capacitance, very large loops, or loops for use at MF or HF. Measurement methods which resonate the inductor at the intended operating frequency would then be highly desirable, although more cumbersome. Cheers, Jim Moritz 73 de M0BMU