Return-Path: Received: from mtain-de04.r1000.mx.aol.com (mtain-de04.r1000.mx.aol.com [172.29.64.204]) by air-da04.mail.aol.com (v129.4) with ESMTP id MAILINDA044-86644c45e41cd7; Tue, 20 Jul 2010 13:59:56 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-de04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 98072380000A0; Tue, 20 Jul 2010 13:59:54 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ObH5l-000397-78 for rs_out_1@blacksheep.org; Tue, 20 Jul 2010 18:58:57 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ObH5k-00038y-MP for rsgb_lf_group@blacksheep.org; Tue, 20 Jul 2010 18:58:56 +0100 Received: from out1.ip02ir2.opaltelecom.net ([62.24.128.238]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1ObH5j-00084O-S4 for rsgb_lf_group@blacksheep.org; Tue, 20 Jul 2010 18:58:56 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AgEFAEqARUxOk8yU/2dsb2JhbACPYJANccEHhTIEixo X-IronPort-AV: E=Sophos;i="4.55,233,1278284400"; d="scan'208,217";a="329313657" Received: from unknown (HELO xphd97xgq27nyf) ([78.147.204.148]) by out1.ip02ir2.opaltelecom.net with SMTP; 20 Jul 2010 18:58:48 +0100 Message-ID: <002301cb2835$31554280$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <4C44B478.7000109@iup.uni-heidelberg.de> <4C45E1CA.6010003@iup.uni-heidelberg.de> Date: Tue, 20 Jul 2010 18:58:43 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Re: earth antenna Content-Type: multipart/alternative; boundary="----=_NextPart_000_0020_01CB283D.92E52D00" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=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-sid: 3039ac1d40cc4c45e41a54d0 X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_0020_01CB283D.92E52D00 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Stefan Keep climbing until you get enough height for an airborne Antenna., tr= y a 300metre tree in the black forest, I might hear you then g3kev ----- Original Message -----=20 From: Stefan Sch=E4fer=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, July 20, 2010 6:50 PM Subject: VLF: earth antenna Dear VLF, Today i was in the forest for more than 10 hours doing the following= tests/works :-) : Today i did my test on 8,97 and 7,97 and 6,97 kHz. It was possible= to transmit on the lower frequencies like one can still see on my gra= bber2. The antenna current was just about 220 mA and 130mA in the 8,97= test. There were some problems with a step up transformer in combinat= ion with the big PA, thus the low current (i used a 12V/150V DC/DC con= verter and batteries, not my generator for high power). So the signal= was even 3 dB lower than in the "73" test on 8,97 before some weeks.= On 8,97 the power was 8 dB lower, thus there was no reception on 8,97= today but as we know, it works best on 8,97 in 5km distance. The lowe= r the frequency the more i am again in the near field. This improves= the propagation i suppose. If my 5 km distance could be "utility assisted" like in Rogers tests= is not sure. A wider distance reception has to be done! After that i increased the earth antenna length to 500m, 420m ground= electrode spacing!! :-) The average height above ground is still abou= t 4m. Orientation of the antenna is N<=3D>S. This was a hard work since i had to climb many trees since i had to= cross 2 ways in a hight of about 6m. Since it is a conferous forest,= i have 100s of scratches now but all in all it was a inspiring work= :-). I removed the far ends ground rods and will place them on the new en= d that will be found on thursday! Adding the last 200m part will be ra= ther easy since there are no ways to cross any more and the tree-densi= ty is rather low ;-) Than, i will have a 700m long wire and the ground= electrode distance will be about 600m!! With that antenna i will try= to be received in 50km distance on 8,97 kHz when Michael Oexner is co= ming back from holidays in abt 2 weeks.=20 Before this test i will try to reduce the overall losses below 500= Ohm and do some RX tests watching the new VLF transmitter levels (DHO= 38 and so on). Any bets about the signal increase when increasing the spacing from= 280m to 600m? 73, Stefan/DK7FC ------=_NextPart_000_0020_01CB283D.92E52D00 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Stefan
Keep climbing until you get enough he= ight for an=20 airborne Antenna., try a 300metre tree in the black forest, I might he= ar you=20 then
 
g3kev
 
----- Original Message -----
Sent: Tuesday, July 20, 2010= 6:50=20 PM
Subject: VLF: earth antenna

Dear VLF,

Today i was in the forest for more= than 10=20 hours doing the following tests/works :-) :

Today i did my te= st on=20 8,97 and 7,97 and 6,97 kHz. It was possible to transmit on th= e lower=20 frequencies like one can still see on my grabber2. The antenna curre= nt was=20 just about 220 mA and 130mA in the 8,97 test. There were some proble= ms with a=20 step up transformer in combination with the big PA, thus the low cur= rent (i=20 used a 12V/150V DC/DC converter and batteries, not my generator for= high=20 power). So the signal was even 3 dB lower than in the "73" test on= 8,97 before=20 some weeks. On 8,97 the power was 8 dB lower, thus there was no rece= ption on=20 8,97 today but as we know, it works best on 8,97 in 5km distance. Th= e lower=20 the frequency the more i am again in the near field. This improves= the=20 propagation i suppose.

If my 5 km distance could be "utility= assisted"=20 like in Rogers tests is not sure. A wider distance reception has to= be=20 done!

After that i increased the earth antenna length to= 500m, 420m=20 ground electrode spacing!! :-) The average height above ground= is still=20 about 4m. Orientation of the antenna is N<=3D>S.
This was= a hard work=20 since i had to climb many trees since i had to cross 2 ways in a hig= ht of=20 about 6m. Since it is a conferous forest, i have 100s of scratches= now but all=20 in all it was a inspiring work :-).
I removed the far ends ground= rods and=20 will place them on the new end that will be found on thursday! Addin= g the last=20 200m part will be rather easy since there are no ways to cross any= more and=20 the tree-density is rather low ;-) Than, i will have a 700m long wir= e and the=20 ground electrode distance will be about 600m!! With that antenna i= will try to=20 be received in 50km distance on 8,97 kHz when Michael Oexner is comi= ng back=20 from holidays in abt 2 weeks.
Before this test i will try to red= uce the=20 overall losses below 500 Ohm and do some RX tests watching the new= VLF=20 transmitter levels (DHO38 and so on).

Any bets about the sign= al=20 increase when increasing the spacing from 280m to 600m?

73,= =20 Stefan/DK7FC

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