Return-Path: Received: (qmail 27881 invoked from network); 1 Jul 1999 00:39:10 +0100 Received: from magnet.plus.net.uk (HELO magnet.force9.net) (195.166.128.26) by guiness.force9.net with SMTP; 1 Jul 1999 00:39:10 +0100 Received: (qmail 20264 invoked from network); 30 Jun 1999 23:39:57 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnet.plus.net.uk with SMTP; 30 Jun 1999 23:39:57 -0000 X-Priority: 3 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 10yThk-0007bP-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 28 Jun 1999 06:11:40 +0100 X-MSMail-Priority: Normal Received: from mail2.hamilton-standard.com ([153.4.57.12]) by post.thorcom.com with esmtp (Exim 3.02 #1) id 10yThj-0007bG-00 for rsgb_lf_group@blacksheep.org; Mon, 28 Jun 1999 06:11:40 +0100 Received: from curly.hsd.utc.com by mail2.hamilton-standard.com; (8.9.1/) id BAA18282; Mon, 28 Jun 1999 01:16:52 -0400 (EDT) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from umrsvr.hsd.utc.com by curly.hsd.utc.com; (5.65v3.2/1.1.8.2/27Feb96-0334PM) id AA06502; Mon, 28 Jun 1999 01:10:43 -0400 Received: from nmex01nt.hsd.utc.com by umrsvr.hsd.utc.com; (5.65v3.2/1.1.8.2/27Feb96-0334PM) id AA12037; Mon, 28 Jun 1999 01:10:36 -0400 Received: by nmex01nt.hsd.utc.com with Internet Mail Service (5.5.2448.0) id ; Mon, 28 Jun 1999 07:09:49 +0100 Message-ID: From: "Soegiono, Gamal" To: rsgb_lf_group@blacksheep.org Subject: LF: radiation resistance & reactance Date: Mon, 28 Jun 1999 07:09:49 +0100 X-Mailer: Internet Mail Service (5.5.2448.0) Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Sender: Content-type: text/plain; charset=windows-1252; format=flowed MIME-Version: 1.0 Content-transfer-encoding: 8bit Hello all, here some equations I found in my book regarding radiation resistance of dipoles and monopoles: the original equation based on current profile on dipole/monopole, all other published equations are derivates therof. l=physical half length of dipole [m] d=physical diameter of dipole [m] w=wavelength in [m] f=radian angle k=2*PI*l/w Rs=120 Ohms / (sin^2(k)*INTEGRAL(f=0 to 0.5*PI){[cos(k*sin(f))-cos(k)]^2/cos(f) df} restriction: l/w =< 0.38 simple Approximation Rs=80 Ohms * [1-1.32*(l/w)^2] * tan^2(PI*l/w) restriction: l/w =< 0.25 more simpler Approximation Rs=790 Ohms * (l/w)^2 restriction: l/w =< 0.14 Rs for Monopole above groundplane is half the dipole value in each of above equation, when l=the physical height of the monopole in [m] Additionally the equations to calculate the antenna reactance: l=physical half length of dipole [m] d=physical diameter of dipole [m] w=wavelength in [m] f=radian angle Zw=120 Ohms * [ln(4*l/d) -1] k=2*PI*l/w Xd=X1d-(Zw/(tan(k))) Xm=X1m-(Zw/(tan(k))) restriction: l/w =< 0.25 X1d=552 Ohms * (l/w)^1.85 if 0.14 <= l/w <=0.25 X1d=156 Ohms * (l/w)^1.22 if l/w < 0.14 X1m=276 Ohms * (l/w)^1.85 if 0.14 <= l/w <=0.25 X1m=78 Ohms * (l/w)^1.22 if l/w < 0.14 Best 73 Gamal Soegiono (SWL) 50N01 / 08E27 / JO 40 fa soegiono@nmex01nt.hsd.utc.com