To: rsgb_lf_group@blacksheep.org Date: Tue, 15 Mar 2005 12:30:40 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 X-SPF-Result: relay.thorcom.net: 195.80.0.234 is neither permitted nor denied by domain of southsurf.com X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=failed,HTML_60_70=0.027,HTML_MESSAGE=0.001 Subject: Re: LF: Untuned loops Content-Type: text/html; charset=windows-1252 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_40_50,HTML_MESSAGE 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) Content-transfer-encoding: 8bit

Thanks to all respondees - I knew it was a simple formula and was (theroretically) an exact way of determining field strength. Just need to make sure the input impedance of the voltmeter is significantly higher than the loop impedance to avoid any loading effects.

(Someone here wants to measure the field strength of a transmission in the HF band)

Andy G4JNT

-----Original Message-----
From: markusvester@aol.com <markusvester@aol.com>
To: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
Date: 2005/03/15 10:58
Subject: Re: LF: Untuned loops

Hi Andy

U = omega * µo * H * area

with µo = 4 * pi * 10^-7 Vs/A/m, omega = 2 * pi * f .

73 de Markus, DF6NM

-----Original Message-----
From: Andy <actalbot@southsurf.com>
To: rsgb_lf_group@blacksheep.org
Sent: Tue, 15 Mar 2005 09:01:51 -0000
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