Return-Path: Received: (qmail 2973 invoked from network); 23 Oct 2001 12:46:22 -0000 Received: from unknown (HELO warrior-inbound.services.quay.plus.net) (212.159.14.227) by excalibur.plus.net with SMTP; 23 Oct 2001 12:46:22 -0000 Received: (qmail 29104 invoked from network); 23 Oct 2001 12:46:11 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior with SMTP; 23 Oct 2001 12:46:11 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 15w0oH-0007GA-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 23 Oct 2001 13:37:33 +0100 Received: from protactinium.btinternet.com ([194.73.73.176] helo=protactinium) by post.thorcom.com with esmtp (Exim 3.33 #2) id 15w0oF-0007G0-00 for rsgb_lf_group@blacksheep.org; Tue, 23 Oct 2001 13:37:32 +0100 Received: from [213.122.101.7] (helo=dave) by protactinium with smtp (Exim 3.22 #6) id 15w0na-0001GU-00 for rsgb_lf_group@blacksheep.org; Tue, 23 Oct 2001 13:36:50 +0100 Message-ID: <000901c15bbf$98619e20$07657ad5@dave> From: "Dave Sergeant" To: "rsgb_lf_group" References: Subject: LF: Re:LF Loading coil designs Date: Tue, 23 Oct 2001 13:35:37 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: >From Dave G3YMC First apologies if one of my mails to Steve GW4ALG got posted on the reflector - 'pressed the wrong button' as they say! Following this discussion, I suggest the following. One standard bucket (UK size) can be wound with exactly 100m of 16/.2 pvc wire and gives an inductance of 3mH. I have two of these and arrange them concentrically. Moving the buckets inside each other gives a reasonable control of the combined inductance (I require 6.5mH to resonate my top loaded Butternut). One bucket is tapped every 20 turns, for coarse adjustment of the inductance. A suitable clamp to hold the inner bucket is made out of a compressed wad of paper, though the more mechanically minded could design something less Heath Robinson! If I remember correctly the dc resistance is a few ohms and quite acceptable for most powers compared with earth losses. This should work in most situations, however the earth losses of 400 ohms at this QTH dampen the resonance such that the tuning is very broad. I hope to get something about verticals on my website in due course, however I am most disappointed with its performance here - initial tests show my loop is quite a few dB better. 73s Dave G3YMC dsergeant@iee.org dsergeant@btinternet.com http://www.dsergeant.btinternet.co.uk