Return-Path: Received: from mtain-mb05.r1000.mx.aol.com (mtain-mb05.r1000.mx.aol.com [172.29.96.25]) by air-mc06.mail.aol.com (v129.4) with ESMTP id MAILINMC062-a9744d07ba09399; Tue, 14 Dec 2010 13:40:09 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mb05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 7AD34380001D7; Tue, 14 Dec 2010 13:40:04 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PSZmR-0001Qh-Ek for rs_out_1@blacksheep.org; Tue, 14 Dec 2010 18:39:19 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PSZmQ-0001QY-Tn for rsgb_lf_group@blacksheep.org; Tue, 14 Dec 2010 18:39:18 +0000 Received: from out1.ip07ir2.opaltelecom.net ([62.24.128.243]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PSZmO-00063d-8I for rsgb_lf_group@blacksheep.org; Tue, 14 Dec 2010 18:39:18 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEAFdIB01OlrfA/2dsb2JhbACkEHjCNIVKBIFgjEs X-IronPort-AV: E=Sophos;i="4.59,343,1288569600"; d="scan'208,217";a="472158399" Received: from unknown (HELO xphd97xgq27nyf) ([78.150.183.192]) by out1.ip07ir2.opaltelecom.net with SMTP; 14 Dec 2010 18:39:10 +0000 Message-ID: <006801cb9bbe$2f47b070$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <80E0204D3E534137903FE0B8E499597F@IBM7FFA209F07C> <4D0783FC.3090107@iup.uni-heidelberg.de> <4D07B3A2.80409@iup.uni-heidelberg.de> Date: Tue, 14 Dec 2010 18:39:04 -0000 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: Re: LF: Earth Electrodes Content-Type: multipart/alternative; boundary="----=_NextPart_000_0065_01CB9BBE.2EE12670" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_30_40,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: 3039ac1d60194d07ba040ce8 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_0065_01CB9BBE.2EE12670 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Stefan you are using a LOSSY dipole and not an earth mode antenna as= you claim and what height above ground are the WIRES ? Are the wires= running parallel or are they diagonal ?=20 You and others are not answering the questions asked.=20 Each individual has a different opinion about what an Earth mode anten= na is. There can only be one defination It seems to me these antennas are really ELEVATED radiators and ineffi= cient as well de g3kev ----- Original Message -----=20 From: Stefan Sch=E4fer=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, December 14, 2010 6:12 PM Subject: Re: LF: Earth Electrodes Chris, LF, Am 14.12.2010 17:27, schrieb Chris:=20 HiStefan, Yes, but 600m is VERY long! The wire even laying on the ground I= would expect to radiate quite well at 137 with that length! And how= many watts?? ERP?? I am sure 8970 would do well through the ground at the sort of pow= ers being spoken about. Probably ideal for submarines, as Roger says! Vy 73, Chris, G4AYT. Well, my earth antenna is grounded at the ends and TX power was abou= t 250 W. The mode was DFCW-600. The receiver was at Michael Oexner usi= ng a PA0RDT design. ERP? No idea, probably some few uW. Its not so eas= y to calculate the losses. Yes, on 137 kHz the wire length comes close to lambda/4 and above so= it acts not just like a pure earth antenna but rather as a combinatio= n of this and a very loss dipole. On 137, my power was 100 W at this= test. The antenna was built to do local tests but seems to work suitable= on 137. So it is a fixed antenna, my only fixed one. And it is a very= quiet location. This makes it interesting to use it as a RX antenna= too!... 73, Stefan ----- Original Message -----=20 From: Stefan Sch=E4fer=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, December 14, 2010 2:49 PM Subject: Re: LF: Earth Electrodes Hi Chris, But how do you explain that i have crossed 49.6 km with a 600m= spaced earth electrode antenna on 8970 Hz? It was rather summer time= than winther (regarding QRN)! With the same antenna, my 137 kHz signa= l was seen 20 dB above noise near Paris in DFCW-3!????? 73, Stefan Am 14.12.2010 15:15, schrieb Chris:=20 Hi Mal, Yes, that is what I had concluded years ago. No harm in trying= though! Further to your previous e-mail to LF, looks to me like beacon= s are now becoming the norm on 136/7kHz band and below. I have no prob= lem with that personally, indeed, I think it preferable to a QSO takin= g forever! I woud like to see full idents though, no matter how slow. Vy 73, Chris, G4AYT. ------=_NextPart_000_0065_01CB9BBE.2EE12670 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Stefan you are using a LOSSY dipole= and not an=20 earth mode antenna as you claim and what height above ground are the= WIRES ? Are=20 the wires running parallel or are they diagonal ?
You and others are not answering the= questions=20 asked.
Each individual has a different opini= on about what=20 an Earth mode antenna is. There can only be one defination
It seems to me these antennas are rea= lly ELEVATED=20 radiators and inefficient as well
de g3kev
 
----- Original Message -----
Sent: Tuesday, December 14,= 2010 6:12=20 PM
Subject: Re: LF: Earth Electr= odes

Chris, LF,

Am 14.12.2010 17:27, schrieb Chris:= =20
HiStefan,
Yes, but 600m is VERY long! The= wire even=20 laying on the ground I would expect to radiate quite well at 137= with that=20 length! And how many watts?? ERP??
I am sure 8970 would do well = through the=20 ground at the sort of powers being spoken about. Probably ide= al for=20 submarines, as Roger says!
Vy 73, Chris,=20 G4AYT.
Well, my earth antenna is grounded= at the ends=20 and TX power was about 250 W. The mode was DFCW-600. The receiver wa= s at=20 Michael Oexner using a PA0RDT design. ERP? No idea, probably some fe= w uW. Its=20 not so easy to calculate the losses.

Yes, on 137 kHz the wire= length=20 comes close to lambda/4 and above so it acts not just like a pure ea= rth=20 antenna but rather as a combination of this and a very loss dipole.= On 137, my=20 power was 100 W at this test.

The antenna was built to do loc= al tests=20 but seems to work suitable on 137. So it is a fixed antenna, my only= fixed=20 one. And it is a very quiet location. This makes it interesting to= use it as a=20 RX antenna too!...

73, Stefan

-----=20 Original Message -----
Sent:=20 Tuesday, December 14, 2010 2:49 PM
Subject:=20 Re: LF: Earth Electrodes

Hi Chris,

But how do you explain that i ha= ve crossed=20 49.6 km with a 600m spaced earth electrode antenna on 8970 Hz?= It was=20 rather summer time than winther (regarding QRN)! With the same= antenna, my=20 137 kHz signal was seen 20 dB above noise near Paris in=20 DFCW-3!?????

73, Stefan


Am 14.12.2010 15:15,= schrieb=20 Chris:=20
Hi Mal,
Yes, that is what I had concl= uded years=20 ago. No harm in trying though!
Further to your previous e-ma= il to LF,=20 looks to me like beacons are now becoming the norm on 136/7kHz= band and=20 below. I have no problem with that personally, indeed, I think= it=20 preferable to a QSO taking forever! I woud like to see full id= ents=20 though, no matter how slow.
Vy 73,
Chris,=20 G4AYT.
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