Return-Path: Received: (qmail 2488 invoked from network); 12 Feb 2002 20:49:11 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by exhibition.plus.net with SMTP; 12 Feb 2002 20:49:11 -0000 Received: (qmail 17225 invoked from network); 12 Feb 2002 20:49:04 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 12 Feb 2002 20:49:04 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16ajpT-0001os-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 12 Feb 2002 20:47:07 +0000 Received: from fep01.swip.net ([130.244.199.129] helo=fep01-svc.swip.net) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16ajpS-0001on-00 for rsgb_lf_group@blacksheep.org; Tue, 12 Feb 2002 20:47:06 +0000 Received: from oemcomputer ([213.101.40.209]) by fep01-svc.swip.net with SMTP id <20020212204616.BOCP23536.fep01-svc.swip.net@oemcomputer> for ; Tue, 12 Feb 2002 21:46:16 +0100 Message-ID: <00c901c1b406$6b301040$072565d5@oemcomputer> From: "Johan Bodin" To: rsgb_lf_group@blacksheep.org References: <001a01c19a31$655db6c0$466152d5@it> Subject: LF: Re: Vertical grounded tower for LF antenna. Date: Tue, 12 Feb 2002 21:46:07 +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 6.00.2600.0000 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: Hi All Giulio Scaroni wrote: >But wich may be the best sistem on this tower for LF, is possible to feed directly it, may be at the top? Oh.. I wish I had such a tower! One idea is to make a top hat of wires fanning out radially from the top of the tower, sloping as little as possible. Feed the antenna between the top hat and the top of the tower - the current running down the tower will create the "vertical ampere-meters" that radiate. Assuming the tower is well grounded, put a loading coil between the tower top and the topload "umbrella". Feed via coax to a link winding on the "cold" side of the loading coil. An alternative to link coupling is to put a matching transformer between the cold end of the coil and the top of the tower. The coax feeds the primary winding. A remotely controlled variometer up there will do wonders. 73 de Johan (Giovanni) SM6LKM