Return-Path: Received: (qmail 7067 invoked from network); 12 Feb 2002 19:39:34 -0000 Received: from unknown (HELO warrior.services.quay.plus.net) (212.159.14.227) by exhibition.plus.net with SMTP; 12 Feb 2002 19:39:34 -0000 Received: (qmail 20820 invoked from network); 12 Feb 2002 19:39:27 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior.services.quay.plus.net with SMTP; 12 Feb 2002 19:39:27 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16aijc-0001fk-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 12 Feb 2002 19:37:00 +0000 Received: from mail3.svr.pol.co.uk ([195.92.193.19]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16aijb-0001ff-00 for rsgb_lf_group@blacksheep.org; Tue, 12 Feb 2002 19:36:59 +0000 Received: from modem-123.aranel.dialup.pol.co.uk ([62.136.119.123] helo=g3aqc) by mail3.svr.pol.co.uk with smtp (Exim 3.13 #0) id 16aiil-0000i9-00 for rsgb_lf_group@blacksheep.org; Tue, 12 Feb 2002 19:36:08 +0000 Message-ID: <001901c1b3fc$a9ee9400$05e9fea9@g3aqc> From: "Laurie Mayhead" 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 19:36:18 -0000 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

----- Original Message -----

From: Giulio Scaroni

Subject: LF: Vertical grounded tower for LF antenna.

But wich may be the best sistem on this tower for LF, is possible to feed directly it, may be at the top?

Any idea??

Hi Giulio, what a great opportunity to experiment !

I don't think there is any way to excite the tower directly, I assume that there is not another high support near by,so a sloping wire will be the best solution, fed at the low end against a good ground (it might be a good idea to link the bottom of the tower to this point also).

In my experience the further away the wire is from lossy or grounded structures the better,also a vertical wire should be as near vertical as possible ! here we have two conflicting requirments so the best compromise will be a wire at 45deg. Well that's my first solution and it is possibly what you used for our contact.

However I would like to experiment with another possibility:-

Join the sloping wire to the top of the tower, making a very large grounded loop.

Of course it will be low impedance so all the requirments for thick wire apply,but

it will be so large that perhaps this will not be so important as for a smaller structure.

Well its an idea, and perhaps you would like to try it. But if not the signal you had was very good so I hope to hear you again soon. 73s Laurie.