Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mb05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 081E838001010; Wed, 4 Jan 2012 15:51:39 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1RiXmy-0005fq-O4 for rs_out_1@blacksheep.org; Wed, 04 Jan 2012 20:50:24 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1RiXmy-0005fh-0i for rsgb_lf_group@blacksheep.org; Wed, 04 Jan 2012 20:50:24 +0000 Received: from mailout-de.gmx.net ([213.165.64.22]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1RiXmv-0005LK-Kz for rsgb_lf_group@blacksheep.org; Wed, 04 Jan 2012 20:50:23 +0000 Received: (qmail invoked by alias); 04 Jan 2012 20:50:15 -0000 Received: from p4FD0A530.dip.t-dialin.net (EHLO Clemens04) [79.208.165.48] by mail.gmx.net (mp072) with SMTP; 04 Jan 2012 21:50:15 +0100 X-Authenticated: #17214767 X-Provags-ID: V01U2FsdGVkX1/+Kxx5UuL+D5boaAP6xo/CByaxZwy6thWNm7y0jU o1PbEKvzTLWavj Message-ID: <017301cccb22$75f61590$1502a8c0@Clemens04> From: "Clemens Paul" To: References: <008301ccc97c$51d9fcf0$0401a8c0@xphd97xgq27nyf>, ,<003501ccca06$6bdef490$0401a8c0@xphd97xgq27nyf> <4F02F9EA.1090101@iup.uni-heidelberg.de> <004601ccca20$8aa7d1c0$0401a8c0@xphd97xgq27nyf> <00fc01ccca65$47277e60$1502a8c0@Clemens04> <00d901ccca69$1f897260$0401a8c0@xphd97xgq27nyf> <024c01cccad1$3c099ba0$1502a8c0@Clemens04> <001901cccad5$bff43840$0401a8c0@xphd97xgq27nyf> Date: Wed, 4 Jan 2012 21:50:09 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3664 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3664 X-Y-GMX-Trusted: 0 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Antennas Content-Type: multipart/alternative; boundary="----=_NextPart_000_016F_01CCCB2A.D45B25F0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: 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-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:419989280:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d60194f04bbdb48ab X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_016F_01CCCB2A.D45B25F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Mal >It depends what you mean by a reasonable sized loop. Using the calculator at http://www.66pacific.com/calculators/small_tx_loop_calc.aspx you can play with circumference and diameter. E.g. with 4x2m and 2cm tube diameter you would come out at ~ -56dB for 137kHz (4x3m and 1cm would be better by 2dB and so on). So a RX noise figure of about 15dB would be necessary to have a SNR margin of 5-10dB. Good MW/LF receivers have such noise figures (at least I know one). 4x2m seems to turn out as the lowest reasonable limit with a sensitive RX. 73 Clemens DL4RAJ ----- Original Message ----- From: mal hamilton To: rsgb_lf_group@blacksheep.org Sent: Wednesday, January 04, 2012 12:41 PM Subject: Re: LF: Antennas : 2109/4121 - Ausgabedatum: 03.01.2012 ------=_NextPart_000_016F_01CCCB2A.D45B25F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Mal
 
>It depends what you mean by a reasonable = sized=20 loop.
 
Using the calculator at
htt= p://www.66pacific.com/calculators/small_tx_loop_calc.aspx
you can play with circumference and=20 diameter.
E.g. with 4x2m and 2cm tube diameter = you would come=20 out at ~ -56dB for 137kHz
(4x3m and 1cm would be better by 2dB = and so=20 on).
So a RX  noise figure of about = 15dB would be=20 necessary to have a SNR margin of 5-10dB.
Good MW/LF receivers have such noise = figures (at=20 least I know one).
4x2m seems to turn out as the lowest = reasonable=20 limit with a sensitive RX.
 
73
Clemens
DL4RAJ
----- Original Message -----
From:=20 mal=20 hamilton
Sent: Wednesday, January 04, = 2012 12:41=20 PM
Subject: Re: LF: Antennas

: 2109/4121 - Ausgabedatum: 03.01.2012 =
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