Return-Path: Received: from mtain-mj01.r1000.mx.aol.com (mtain-mj01.r1000.mail.aol.com [172.21.164.85]) by air-mc07.mail.aol.com (v129.4) with ESMTP id MAILINMC074-a97e4c3ec477338; Thu, 15 Jul 2010 04:19:03 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mj01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 73D2F380000BA; Thu, 15 Jul 2010 04:18:56 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OZJba-0007Gf-Gc for rs_out_1@blacksheep.org; Thu, 15 Jul 2010 09:15:42 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OZJbZ-0007GW-KI for rsgb_lf_group@blacksheep.org; Thu, 15 Jul 2010 09:15:41 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OZJbV-0000t9-PW for rsgb_lf_group@blacksheep.org; Thu, 15 Jul 2010 09:15:41 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id o6F8FQTQ023976 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 15 Jul 2010 10:15:28 +0200 Received: from [129.206.29.99] (pc99.iup.uni-heidelberg.de [129.206.29.99]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id o6F8FQFR029617 for ; Thu, 15 Jul 2010 10:15:26 +0200 Message-ID: <4C3EC35F.2040600@iup.uni-heidelberg.de> Date: Thu, 15 Jul 2010 10:14:23 +0200 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4C363DCD.303@iup.uni-heidelberg.de>,<4C3650A1.6040104@iup.uni-heidelberg.de> ,<4C3DA75D.80407@iup.uni-heidelberg.de> ,<263121BD51374246B3F184A43B2E9619@JimPC> <4C3E27D4.3060407@iup.uni-heidelberg.de>, In-Reply-To: X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: RE: RE: DLF passive received with earth antenna Content-Type: multipart/alternative; boundary="------------000509000404040004010006" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.1 required=5.0 tests=HTML_20_30,HTML_FONTCOLOR_BLUE, HTML_MESSAGE,HTML_TITLE_EMPTY 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-sid: 3039400c89a24c3ec4700f16 X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : temperror X-Mailer: Unknown (No Version) --------------000509000404040004010006 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hello Rik, Assume, i will increase the wire length or electrode spacing to 1200m this will not only be a full size dipole for 137 kHz but on 9 kHz the area might become 480000 m^2. Then, 1,75 A is needed. Even that is not really easy. So it will stay a rather ineffective antenna, compared to the kite antenna. But it is an interesting field and i want to know how it works on 137 kHz and how it can be matched and so on ;-) Maybe i will discover that the DHO level is even lower than -94 dB, than the effective area could be even more ;-) Or if the ERP of DHO38 is lower than 100 kW... We will see... Tnx for taking part on the discussion :-) 73, Stefan Am 15.07.2010 09:40, schrieb Rik Strobbe: > > Dear Jim, Stefan, LF group, > > /BTW, if my guess of 5mV/m is correct, and the loop EMF is 44mV, the > effective loop area would be about 18000m^2... > / > that sounds impressive, based on the antenna length (280m) the "hight" > of the loop would be 64m. > > At 9kHz the radiation resistance of a 18000 m^2 loop is a mere 8 > micro-Ohm, thus a current of 11A is needed to radiate 1mW. > > But as the penetration depth into the earth is inverse proportional to > the square root of the frequency the effective loop area at 9kHz might > be 29000 m^2, increasing the radiation resistance to over 20 > micro-Ohm. What means that 7A antenna current is need to get 1mW radiated. > > But even that would require many kW. > > 73, Rik ON7YD > ________________________________________ > Van: owner-rsgb_lf_group@blacksheep.org > [owner-rsgb_lf_group@blacksheep.org] namens James Moritz > [james.moritz@btopenworld.com] > Verzonden: donderdag 15 juli 2010 1:40 > Aan: rsgb_lf_group@blacksheep.org > Onderwerp: LF: RE: DLF passive received with earth antenna > > --------------000509000404040004010006 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hello Rik,

Assume, i will increase the wire length or electrode spacing to 1200m this will not only be a full size dipole for 137 kHz but on 9 kHz the area might become 480000 m^2. Then, 1,75 A is needed. Even that is not really easy. So it will stay a rather ineffective antenna, compared to the kite antenna. But it is an interesting field and i want to know how it works on 137 kHz and how it can be matched and so on ;-)

Maybe i will discover that the DHO level is even lower than -94 dB, than the effective area could be even more ;-) Or if the ERP of DHO38 is lower than 100 kW... We will see...

Tnx for taking part on the discussion :-)

73, Stefan


Am 15.07.2010 09:40, schrieb Rik Strobbe:

Dear Jim, Stefan, LF group,

BTW, if my guess of 5mV/m is correct, and the loop EMF is 44mV, the effective loop area would be about 18000m^2...

that sounds impressive, based on the antenna length (280m) the "hight" of the loop would be 64m.

At 9kHz the radiation resistance of a 18000 m^2 loop is a mere 8 micro-Ohm, thus a current of 11A is needed to radiate 1mW.

But as the penetration depth into the earth is inverse proportional to the square root of the frequency the effective loop area at 9kHz might be 29000 m^2, increasing the radiation resistance to over 20 micro-Ohm. What means that 7A antenna current is need to get 1mW radiated.

But even that would require many kW.

 

73, Rik  ON7YD
________________________________________
Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens James Moritz [james.moritz@btopenworld.com]
Verzonden: donderdag 15 juli 2010 1:40
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: LF: RE: DLF passive received with earth antenna


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