Return-Path: Received: (qmail 12092 invoked from network); 17 Feb 2000 08:52:15 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by dimple.core.plus.net.uk with SMTP; 17 Feb 2000 08:52:15 -0000 Content-Type: text/plain; charset=iso-8859-1; format=flowed Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 12LMZu-0006ax-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 17 Feb 2000 08:46:26 +0000 Content-Transfer-Encoding: 8bit Received: from finch-post-10.mail.demon.net ([194.217.242.38]) by post.thorcom.com with esmtp (Exim 3.02 #1) id 12LMZn-0006as-00 for rsgb_lf_group@blacksheep.org; Thu, 17 Feb 2000 08:46:19 +0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from dennison.demon.co.uk ([194.222.239.33]) by finch-post-10.mail.demon.net with smtp (Exim 2.12 #1) id 12LMZf-0002VL-0A for rsgb_lf_group@blacksheep.org; Thu, 17 Feb 2000 08:46:11 +0000 Message-ID: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Date: Thu, 17 Feb 2000 08:44:37 +0000 To: rsgb_lf_group@blacksheep.org From: "Mike Dennison" Subject: Re: LF: Re. Folded dipoles and meander ants. In-reply-to: <200002170038_MC2-9986-B9BD@compuserve.com> MIME-Version: 1.0 X-Mailer: Turnpike Version 3.03a Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: >I know that the idea of the top load is to get more capacity in the air. >owever, I have read an article somewhere about toploads of a short vertical >being equipped with coils to improve or to "lengthen" the top load wires >electrically. Any experience with that? Would that do any good? >Geri, DK8KW (W1KW) > That is effectively what I do with a coil at the top of the vertical section, before the three parallel top wires. The positive effect of raising the current higher up the vertical section must be balanced against the losses from the coil. It certainly works for me, and I have tried it both at home where the vertical section is close to the house, and portable in an open field. There is, however, an argument that maximum benefit is when the lower part of the vertical has some local screening by buildings and trees. It's worth a try. I have described my light-weight loading coil here before but if anyone wants it again, I will post it on my web site or e-mail direct. Incidentally, I have had great success using my inverted-L on 160m by using two coils - one at the top of the vertical, and one a few metres along the horizontal. This seemed to work better than a single top coil. I am not sure why, but it may have increased the amount of current in the short horizontal section between the two coils and tailored the angle of radiation to just what was needed. Not necessarily what we want at LF, but again well worth a try. If we lose the will to experiment "outside the box" we might as well give up. -- Mike, G3XDV IO91VT http://www.dennison.demon.co.uk/activity.htm