Return-Path: Received: (qmail 20121 invoked from network); 8 Jun 2002 03:00:42 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 8 Jun 2002 03:00:42 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 3473 invoked from network); 8 Jun 2002 03:00:17 -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; 8 Jun 2002 03:00:17 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 17GVNZ-0006Gr-00 for rsgb_lf_group-outgoing@blacksheep.org; Sat, 08 Jun 2002 02:50:57 +0100 Received: from imo-m04.mx.aol.com ([64.12.136.7]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 17GVNX-0006Fr-00 for rsgb_lf_group@blacksheep.org; Sat, 08 Jun 2002 02:50:56 +0100 Received: from MarkusVester@aol.com by imo-m04.mx.aol.com (mail_out_v32.5.) id l.fc.19179bb5 (4364) for ; Fri, 7 Jun 2002 21:19:05 -0400 (EDT) From: MarkusVester@aol.com Message-ID: Date: Fri, 7 Jun 2002 21:19:05 EDT Subject: Re: LF: Counterpoise Experiment To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 8bit X-Mailer: AOL 4.0.i for Windows 95 sub 72 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi Jim, thank you for reporting these very interesting experiments. I wonder if you could optimize the shielding effectiveness of the counterpoise by connecting it via a variable inductor to ground, thus inducing an adjustable opposite-polarity voltage to nullify the displacement current into the earth. If I remember right, the technique was shown in the circuit diagrams of SAQ's antenna system. - A few years ago, we applied the same principle to effectively neutralize a tetrode amplifier at 40 MHz, using its screen-grid lead inductance. My LF antenna is mostly above our roof, which has a thin aluminium vapor-diffiusion barrier beneath it. A while ago I found that explicitely connecting parts of the foil to TX ground reduced the antenna resistance from 32 to 30 ohms (and less noise-pickup from devices within the house). Judging from the large variations seen during frost periods, I believe a large part of the remaining loss is due to the capacitive coupling to nearby trees. 73 Markus, DF6NM