Return-Path: Received: (qmail 10113 invoked from network); 15 Mar 2005 10:27:23 -0000 Received: from unknown (HELO ptb-spamcore01.plus.net) (192.168.71.1) by ptb-mailstore01.plus.net with SMTP; 15 Mar 2005 10:27:23 -0000 Received: from mailnull by ptb-spamcore01.plus.net with spamcore-i (Exim 4.32; FreeBSD) id 1DB9KI-0002OY-G3 for dave@picks.force9.co.uk; Tue, 15 Mar 2005 10:31:02 +0000 Received: from [192.168.67.1] (helo=ptb-mxcore01.plus.net) by ptb-spamcore01.plus.net with esmtp (Exim 4.32; FreeBSD) id 1DB9KI-0002OV-Bp for dave@picks.force9.co.uk; Tue, 15 Mar 2005 10:31:02 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim) id 1DB9JX-0005dy-G0 for dave@picks.force9.co.uk; Tue, 15 Mar 2005 10:30:15 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1DB9GG-0004yG-EP for rs_out_1@blacksheep.org; Tue, 15 Mar 2005 10:26:52 +0000 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1DB9GF-0004y7-7V for rsgb_lf_group@blacksheep.org; Tue, 15 Mar 2005 10:26:51 +0000 Received: from grunt14.ihug.co.nz ([203.109.254.61]) by relay.thorcom.net with esmtp (Exim 4.43) id 1DB9GC-0000kD-Gs for rsgb_lf_group@blacksheep.org; Tue, 15 Mar 2005 10:26:51 +0000 Received: from 203-173-167-64.bliink.ihug.co.nz (athlon1200) [203.173.167.64] by grunt14.ihug.co.nz with esmtp (Exim 3.35 #1 (Debian)) id 1DB9G5-000128-00; Tue, 15 Mar 2005 23:26:41 +1300 Received: from 127.0.0.1 (AVG SMTP 7.0.308 [266.7.2]); Tue, 15 Mar 2005 23:23:57 +1300 Message-ID: <041901c52949$18f41d10$7900a8c0@athlon1200> From: "Dave Brown" To: rsgb_lf_group@blacksheep.org References: <000d01c5293d$a1ddf8f0$0e8cf8d4@standalone> Date: Tue, 15 Mar 2005 23:23:57 +1300 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Mime-Version: 1.0 X-SPF-Result: relay.thorcom.net: 203.109.254.61 is neither permitted nor denied by domain of ihug.co.nz X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=failed,none Subject: LF: Re: Untuned loops Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=iso-8859-1; format=flowed X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Filtered: by PlusNet SpamCORE (v3.00) Loop induced emf(volts) = 2*pi*(field strength in v/m)*(loop area in sq. metres)* (loop turns)/wavelength. Which for the single turn untuned circular loop case, can be simplified to; Loop induced emf (microvolts) = 16.449*freq(kHz)*loopdia(m)*loopdia(m)*field strength(v/m) Ref: Terman, "Radio Engineering", Section 11, Para 18. Dave, ZL3FJ ----- Original Message ----- From: "Andy" To: Sent: Tuesday, March 15, 2005 10:01 PM Subject: LF: Untuned loops Can anyone recall this equation, I know it was mentioned on this reflector before... What is the output voltage for an untuned small loop into an arbitrarily high impedance? It is proportional to H, and presumably F^2, and I seem to recall it is an absolute value, virtually un-influenced by losses, conductor diameter etc. Therefore can be used for accurate H field (and hence far field radiation) signal strength measurements. Andy G4JNT -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.7.2 - Release Date: 11/03/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.7.2 - Release Date: 11/03/2005