Return-Path: Received: (qmail 19745 invoked from network); 20 Sep 1999 10:08:53 +0100 Received: from magnet.plus.net.uk (HELO magnet.force9.net) (195.166.128.26) by guiness.force9.net with SMTP; 20 Sep 1999 10:08:53 +0100 Received: (qmail 32718 invoked from network); 20 Sep 1999 09:13:27 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnet.plus.net.uk with SMTP; 20 Sep 1999 09:13:27 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 11SzHy-00051V-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 20 Sep 1999 09:59:10 +0100 Received: from mserv1c.u-net.net ([195.102.240.33]) by post.thorcom.com with esmtp (Exim 3.02 #1) id 11SzHx-00051Q-00 for rsgb_lf_group@blacksheep.org; Mon, 20 Sep 1999 09:59:09 +0100 X-Priority: 3 X-MSMail-Priority: Normal Received: from rsgb.u-net.com ([195.102.80.225] helo=rsgb.org.uk) by mserv1c.u-net.net with smtp (Exim 2.10 #34) id 11T0Aq-00059l-00 for rsgb_lf_group@blacksheep.org; Mon, 20 Sep 1999 09:55:53 +0000 Received: from miked by rsgb.org.uk with SMTP (MDaemon.v2.7.SP5.R) for ; Mon, 20 Sep 1999 09:59:45 +0100 From: "Mike Dennison" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Organization: Radio Society of Great Britain To: rsgb_lf_group@blacksheep.org Date: Mon, 20 Sep 1999 09:59:44 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 8bit Subject: LF: New antenna X-Mailer: Pegasus Mail for Win32 (v3.11) X-MDaemon-Deliver-To: rsgb_lf_group@blacksheep.org X-Return-Path: miked@mail.rsgbhq Message-ID: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Spent most of this weekend putting into action plans for a better antenna (both physically and electrically) which I have been drawing up for some time. The result - still an inverted-L -is a slightly higher vertical section, a mast that does not need to be taken down in the wind, and three top wires 0.7m apart at the vertical end and 1m apart at the far end. The frequency dropped from 137kHz to 122kHz, a 12 per cent change. I have not yet compared these with Dick's predicted capacitance changes. On receive it performs better with slightly stronger signals and less noise. On transmit, I was disappointed to get less current (even after a lot of fiddling with the matching transformer). I expected more current. My first reaction was to think that the antenna impedance had gone up but I think that would be swamped by the earth resistance in any case. Anyone got any ideas? Reports from GW4ALG and G8RW appeared to show that it was at least as good as my single wire top section, despite the current reduction. Mike, G3XDV (IO91VT) http://www.dennison.demon.co.uk/activity.htm