Return-Path: Received: (qmail 17687 invoked from network); 2 Aug 2003 10:45:24 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by netmail00.services.quay.plus.net with SMTP; 2 Aug 2003 10:45:24 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 7063 invoked from network); 2 Aug 2003 10:45:26 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 2 Aug 2003 10:45:26 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.14) id 19itsA-0001Fs-7T for rsgb_lf_group-outgoing@blacksheep.org; Sat, 02 Aug 2003 11:44:26 +0100 Received: from [152.163.225.103] (helo=imo-r07.mx.aol.com) by post.thorcom.com with esmtp (Exim 4.14) id 19its6-0001Fc-AC for rsgb_lf_group@blacksheep.org; Sat, 02 Aug 2003 11:44:22 +0100 Received: from G0MRF@aol.com by imo-r07.mx.aol.com (mail_out_v36_r1.1.) id l.b7.3495ba76 (3890) for ; Sat, 2 Aug 2003 06:43:45 -0400 (EDT) From: G0MRF@aol.com Message-ID: Date: Sat, 2 Aug 2003 06:43:44 EDT To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 X-Mailer: 8.0 for Windows sub 670 Subject: LF: 500m drums of coax? Content-Type: text/html; charset=windows-1252 X-Spam-Status: No, hits=2.5 required=5.0tests=HTML_10_20,HTML_MESSAGE,MIME_LONG_LINE_QP,NO_REAL_NAMEversion=2.55 X-Spam-Level: ** X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Content-transfer-encoding: 8bit

>Are you making a coax dipole for 136?
>
>73
>John Rabson G3PAI

I've always wondered about dipoles / loops at 136k?
A 'dipole' just lying on rocky ground where the water table is many metres below the surface could be quite effective. The angle of radiation would be poor but the efficiency may not be as bad as first suppossed. One advantage of a big antenna on the ground is that it can't fall down and, for the local planning committe, it's less than 9 feet high.

Some time ago I tried to simulate this by making a dipole for 21MHz and had a number of QSOs through it while gradually lowering it's height and retrimming as I went. I managed to work Romania were I sent "Ant dipole  5cm agl".  I have no idea what the Romanian though of this madness and he didn't stay around long to find out.
Incidentally, at about 2 inches off the ground the antenna was resonant at about 20% less than it's normal 'free space length'. Never did find a big field to try it on 136k.

73

David  G0MRF