Return-Path: Received: (qmail 9974 invoked from network); 25 Apr 1999 23:29:28 +0100 Received: from magnet.plus.net.uk (HELO magnet.force9.net) (195.166.128.26) by guiness.force9.net with SMTP; 25 Apr 1999 23:29:28 +0100 Received: (qmail 23326 invoked from network); 25 Apr 1999 22:29:53 -0000 Received: from post.thorcom.com (194.75.130.70) by magnet.plus.net.uk with SMTP; 25 Apr 1999 22:29:53 -0000 Received: from troy.blacksheep.org ([194.75.183.50] ident=root) by post.thorcom.com with esmtp (Exim 2.04 #3) id 10bXNb-0007GQ-00; Sun, 25 Apr 1999 23:28:03 +0100 X-Priority: 3 Received: (from root@localhost) by troy.blacksheep.org (8.6.12/8.6.12) id WAA08724 for rsgb_lf_group-outgoing; Sun, 25 Apr 1999 22:28:03 GMT X-MSMail-Priority: Normal Received: from post.thorcom.com (root@post.unica.co.uk [194.75.183.70]) by troy.blacksheep.org (8.6.12/8.6.12) with ESMTP id WAA08720 for ; Sun, 25 Apr 1999 22:28:01 GMT Received: from mars.cableol.net ([194.168.4.224]) by post.thorcom.com with smtp (Exim 2.04 #3) id 10bXMw-0007GN-00 for rsgb_lf_group@blacksheep.org; Sun, 25 Apr 1999 23:27:22 +0100 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from miranda-29.cableol.net by mars.cableol.net; (5.65v3.2/1.1.8.2/22Feb96-0403PM) id AA12534; Sun, 25 Apr 1999 23:27:43 +0100 Message-ID: <37239424.FF3C0286@cableol.co.uk> Date: Sun, 25 Apr 1999 23:16:05 +0100 From: "Steve Rawlings" X-Mailer: Mozilla 4.04 [en] (Win95; I) MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Re: Re: Further signals measured (2nd version) References: <01be8e9d$a644f7e0$0100007f@localhost> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 8bit Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Graham Phillips, G3XTZ wrote: > . . . . my vertical is 20 meters high, but the two 10 meter loading > wires from the top have to slope down at about 45 degrees ( to fit in the > available space ). I have always thought that the effective loss of height > was a price worth paying to avoid the need for a much higher value of > loading inductance ( and loss ) at the base of the vertical. . . . . > I would like to hear what others may think of the options: (1) eliminate > the top capacity loading, and wind a bigger loading coil. ( 2 ) Fit a > small, lightweight inductance at the top of the vertical and reduce the > length of the capacity wires. ( 3 ) A combination of both. ( 4 ) Move. > They all sound like good options! I use a basic 12 m vertical with good results. But the improvement with my 8 m balloon-supported extension (making it a 20 m vertical) is significant (perhaps, +6 dB?). So, it seems to me that antenna height is very important. Therefore, I am not keen on using sloping top wires which lower the effective antenna height. On the other hand, I'm quite happy to compensate for the low top capacitance of my vertical by adding a few more mH to the loading coil. I guess I see things differently: for me, the power loss in the additional inductance is a price worth paying to avoid lowering the effective antenna height through the use of sloping top wires! It's now time to try putting some numbers to this puzzle! Any offers? By the way, Graham, if you decide on option (4), I still need GI ; GJ; GU; and GD!! Regards to all, Steve GW4ALG steve.rawlings@cableol.co.uk