Return-Path: Received: (qmail 1715 invoked from network); 11 Jun 2002 09:52:40 -0000 Content-Transfer-Encoding: 8bit Received: from murphys.services.quay.plus.net (212.159.14.225) by mailstore with SMTP; 11 Jun 2002 09:52:40 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 17353 invoked from network); 11 Jun 2002 09:52:08 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.70) by murphys.services.quay.plus.net with SMTP; 11 Jun 2002 09:52:08 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 17Hi89-0007hT-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 11 Jun 2002 10:40:01 +0100 Received: from hestia.herts.ac.uk ([147.197.200.9]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 17Hi88-0007h1-00 for rsgb_lf_group@blacksheep.org; Tue, 11 Jun 2002 10:40:00 +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 17Hi84-0004V1-00 for rsgb_lf_group@blacksheep.org; Tue, 11 Jun 2002 10:39:56 +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 17Hi80-00008R-00 for rsgb_lf_group@blacksheep.org; Tue, 11 Jun 2002 10:39:52 +0100 Message-ID: <5.1.0.14.0.20020611101143.00a7f1b0@gemini.herts.ac.uk> X-Sender: mj9ar@gemini.herts.ac.uk X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Tue, 11 Jun 2002 10:39:38 +0100 To: rsgb_lf_group@blacksheep.org From: "James Moritz" Subject: Re: LF: DJ In-reply-to: <001001c210b3$ad4d2620$abe9fc3e@l8p8y6> 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 Mal, LF Group, At 19:59 10/06/2002 +0100, you wrote: >. Two taps on the coil permits freq adjustment from 135.7 - 137.8 khz... Something is wrong if you need to adjust the tuning within this range - the output should be flat within a fraction of a dB over the whole band without re-tuning. Incidentally, an inductor that works OK for a low pass filter won't necessarily be suitable in this type of tank circuit - in the low pass, the loaded Q of the circuit is usually 1 or less, depending on design, while in the tank circuit it is about 6. This means the tank circuit inductor has to cope with reactive power several times greater than the low-pass inductor for the same power throughput - so beware! Cheers, Jim Moritz 73 de M0BMU