Return-Path: Received: (qmail 4111 invoked from network); 31 Dec 2000 12:36:23 -0000 Received: from unknown (HELO warrior-inbound.servers.plus.net) (212.159.14.227) by 10.226.25.101 with SMTP; 31 Dec 2000 12:36:23 -0000 Received: (qmail 12440 invoked from network); 31 Dec 2000 12:39:37 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior with SMTP; 31 Dec 2000 12:39:37 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #1) id 14Chd7-0000m2-00 for rsgb_lf_group-outgoing@blacksheep.org; Sun, 31 Dec 2000 12:30:29 +0000 Received: from [212.78.195.134] (helo=smtp3.bip.net ident=root) by post.thorcom.com with esmtp (Exim 3.16 #1) id 14Chd6-0000lx-00 for rsgb_lf_group@blacksheep.org; Sun, 31 Dec 2000 12:30:28 +0000 Received: from HemmaPC (t1o940p48.telia.com [194.237.162.48]) by smtp3.bip.net (8.9.3/8.9.0) with SMTP id NAA07829 for ; Sun, 31 Dec 2000 13:30:09 +0100 Message-ID: <000a01c07325$69c9f040$30a2edc2@HemmaPC> From: "Urban ekholm" To: "RSGB" Subject: LF: Loading coil Q Date: Sun, 31 Dec 2000 13:29:13 +0100 MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2615.200 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: Content-transfer-encoding: 8bit

Hello to all !

During the Christmas vacation I found some wire that might be suitable for a loading coil. The wire has a cross section of 4.3 square mm.

I made a coil with a diameter of 38cm and a length of 20cm that gave an inductance of roughly 900uH.

Measuring the coil Q revealed that having the coil elevated about 70cm above the floor (concrete) resulted in a Q of 300 and when putting the coil directly on the floor with the lowest turn about 5cm above the floor the Q was reduced to 220. The first 30 cm seemed to make a big difference. >From 30 up to 70cm did not make much change.

I had expected the Q to decrease, however not that much. The inductance was not very much changed. The change in resonance frequency was barely detectable.

Having seen on homepages that some of you have the coil standing quite close to ground it might be wise to elevate it somewhat.

Wish you all a happy new 2001 !

73 de SM5EUF / Urban