Return-Path: Received: (qmail 41 invoked from network); 16 Sep 1999 13:02:44 +0100 Received: from magnus.plus.net.uk (HELO magnus.force9.net) (195.166.128.27) by guiness.force9.net with SMTP; 16 Sep 1999 13:02:44 +0100 Received: (qmail 168 invoked from network); 16 Sep 1999 12:00:33 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnus.plus.net.uk with SMTP; 16 Sep 1999 12:00:33 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 11RZv1-0004sQ-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 16 Sep 1999 12:41:39 +0100 Received: from [143.179.236.32] (helo=Lesothosaurus.big-orange.net) by post.thorcom.com with esmtp (Exim 3.02 #1) id 11RZux-0004sK-00 for rsgb_lf_group@blacksheep.org; Thu, 16 Sep 1999 12:41:36 +0100 Received: from w8k3f0 ([143.179.150.141]) by Lesothosaurus.big-orange.net (Netscape Messaging Server 3.6) with SMTP id AAA4A50; Thu, 16 Sep 1999 13:41:23 +0200 Message-ID: <004f01bf0039$7741cc80$7497b38f@w8k3f0> From: "Dick Rollema" To: "LF-Group" Cc: "Ger van Went, PA0GER" , "Koos Fockens, PA0KDF" Subject: LF: LF-antenna with top load 2 Date: Thu, 16 Sep 1999 13:48:12 +0200 MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 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
                  
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Further to my report by e-mail of 15 Sept. 1919 hrs I have also simulated by means of a computer program top loads consisting of multiple parallel wires with spacings of 0.5; 1.0; 1.5 and 2.0 m. All wires are of 1.5 mm copper (16 SWG).
The vertical radiator is again 10 m long and the parallel top loading wires are horizontal and 20 m long (inverted L antenna). The first report shows that the characteristics of T- and inverted L-antennas with horizontal tops of the same size are almost identical. So it seems reasonable to assume that the results given in this report for 20 m long multiple parallel wires as top load are applicable to both inverted L and T-antennas.
 
Finally the influence of increasing the height of the antenna from 10 to 15 and 20 metres has been investigated.
 
 
Number of             Spacing between      Rs            C
top load wires        between wires (m)    milli-ohm     pF
 
   1                          -               22             176  
 
 
   2                          0.5               24.9           236
 
   2                          1.0               25.2           247
 
   2                          1.5               25.5           255
 
   2                          2.0               25.7           261
 
 
   3                          0.5               26.1           280
 
   3                          1.0               26.8           304
 
   3                          1.5               27.1           321
 
   3                          2.0               27.3           335
 
 
   4                          0.5               27.1           316
 
   4                          1.0               27.6           353
 
   4                          1.5               28.0           381
 
   4                          2.0               28.2           403
 
 
One horizontal top load wire of 20 m
 
Height (m) of        Rs              C  
vertical radiator    milli-ohm       pF
 
       10               22               176
 
       15               43.7             200
 
       20               70.7             225     
 
 
Four horizontal parallel top load wires of 20 m long and 2 m spacing
 
        10              28.2             403
 
        15              59.3             411
 
        20              99               427
 
 
73, Dick, PA0SE
 
D.W. Rollema
V.d. Marckstraat 5
2352 RA Leiderdorp
Tel. +31 71 589 27 34
E-mail: d.w.rollema@gironet.nl