Return-Path: Received: from mtain-mc09.r1000.mx.aol.com (mtain-mc09.r1000.mx.aol.com [172.29.96.81]) by air-di01.mail.aol.com (v129.4) with ESMTP id MAILINDI011-eab64c6aa9cb39d; Tue, 17 Aug 2010 11:24:59 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mc09.r1000.mx.aol.com (Internet Inbound) with ESMTP id 44D583800018F; Tue, 17 Aug 2010 11:24:57 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OlO17-0005er-70 for rs_out_1@blacksheep.org; Tue, 17 Aug 2010 16:23:57 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OlO16-0005ei-J9 for rsgb_lf_group@blacksheep.org; Tue, 17 Aug 2010 16:23:56 +0100 Received: from out1.ip04ir2.opaltelecom.net ([62.24.128.240]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OlO15-0007ZX-82 for rsgb_lf_group@blacksheep.org; Tue, 17 Aug 2010 16:23:56 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEAG9GakxcEYl//2dsb2JhbACgPnGIJbgHhTcEgVaLCg X-IronPort-AV: E=Sophos;i="4.55,383,1278284400"; d="scan'208,217";a="301926356" Received: from unknown (HELO your91hoehfy9g) ([92.17.137.127]) by out1.ip04ir2.opaltelecom.net with SMTP; 17 Aug 2010 16:23:48 +0100 Message-ID: <006601cb3e20$32db0080$0301a8c0@your91hoehfy9g> From: "mal hamilton" To: References: <4C694CC6.3010609@o2.ie> <1282007441.6432.12.camel@vaio3rd> <1282014113.6432.22.camel@vaio3rd> <1282025562.6432.54.camel@vaio3rd> <000f01cb3de6$040e2780$0301a8c0@your91hoehfy9g> <1282036245.6432.81.camel@vaio3rd> <4C6A5A2D.4040803@iup.uni-heidelberg.de> <002501cb3dfa$26bf9840$0301a8c0@your91hoehfy9g> <4C6A710C.2030603@iup.uni-heidelberg.de> <003e01cb3e00$b7865f70$0301a8c0@your91hoehfy9g> <4C6A767E.3080103@iup.uni-heidelberg.de> <005601cb3e19$dbc16420$0301a8c0@your91hoehfy9g> <4C6AA1B9.8000608@iup.uni-heidelberg.de> Date: Tue, 17 Aug 2010 16:23:52 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Earth electrodes antenna tests[Contest results] Content-Type: multipart/alternative; boundary="----=_NextPart_000_0063_01CB3E28.946D5C00" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.4 required=5.0 tests=HTML_30_40,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: 3039ac1d60514c6aa9c91307 X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_0063_01CB3E28.946D5C00 Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable Tnx Stefan for info. I now understand what u are doing. The audio amp= is convenient for 9 kcs but I will build another class D for 9 kcs ev= entually My 137 amp is class D and 500 is class E all home built. 73 de mal/g3kev ----- Original Message -----=20 From: Stefan Sch=E4fer=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, August 17, 2010 3:50 PM Subject: Re: LF: Earth electrodes antenna tests[Contest results] Mal, I have a 2 uF C in series to the primary coil. I am using a homemade= H bridge switching mode PA. The circuit is currently just in my mind= but maybe i can draw and publish it soon. The impedance level of the= primary side is about 150 Ohm.=20 73, Stefan Am 17.08.2010 16:38, schrieb mal hamilton:=20 Stefan Are u using an audio amp, if so do u have a capacitor in series wi= th the link winding otherwise the winding might appear as an almost sh= ort cct because of the low dc resistance. 73 de mal/g3kev ----- Original Message -----=20 From: Stefan Sch=E4fer=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, August 17, 2010 12:46 PM Subject: Re: LF: Earth electrodes antenna tests[Contest results] Mal, I am using a galvanic decoupled primary winding at the bottom of= the water barrel where the coil is wound on. Adjust the primary numbe= r of turns so that enough power is fed into the system. Watch the phot= o on my qrz.com page named "new amperemeter". There you see the primar= y winding just above the amperemeter. 73, Stefan Am 17.08.2010 13:38, schrieb mal hamilton:=20 Stefan I am talking about matching the amp 8 ohms to 50 ohms not abou= t resonating the antenna. My antenna is already resonated for 9 Kcs,= or 137 as required. I was referring to your kite antenna and what method you used= for matching amp to antenna. de mal/g3kev ----- Original Message -----=20 From: Stefan Sch=E4fer=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, August 17, 2010 12:22 PM Subject: Re: LF: Earth electrodes antenna tests[Contest resu= lts] Mal,=20 Are you talking about a earth electrode antenna or your vert= ical antenna? I assume you mean the vertical ;-) You will get several kV, most probably above 10 kV rms on yo= ur antenna. That's why a ferrite transformer is not a good choice for= a large ( C ) antenna in addition with QRO! For your 5 W tests it may= work with a ferrite coil L but not at 500 W and above. There is no alternative to wind an air coil if you want to= generate a signal that can be watched in the far field.=20 And if you want to generate a signal that can be heared in= CW across EU i recommend a power supply like i had as i worked in Dar= mstadt last year: http://www.hst.tu-darmstadt.de/index.php?id=3D173&L= =3D1 ;-) Transforming to 50 Ohm is not wrong but it is not necessary.= You can just resonate the antenna and match the load to something sui= table for the audio amp (4...8 Ohm). A 50 Ohm impedance level is just= necessary if you want to filter your signal with a precise dimensione= d low pass filter that properly works at 50 Ohm input and output imped= ance (in my opinion). Essential is, that the power is pushed into the= antenna! ;-) 73, Stefan PS: On an earth antenna, which is not resonated (!), you jus= t have to apply a proper output voltage to the antenna that causes the= DC input power at the PA that you want to generate. Am 17.08.2010 12:51, schrieb mal hamilton:=20 Stefan What method do u use to couple the amplifier to the electrodes? Is the= amp output impedence 8 ohms. My method for my antenna using an audio amp would be to use a ferrite transformer to step up the 8 ohms to 50 ohms (x 6.250) turns Prim 8= and Secondary 20 turns. This way I can use my existing test equipment for= swr etc. mal/g3kev =20 ------=_NextPart_000_0063_01CB3E28.946D5C00 Content-Type: text/html; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable
 
Tnx Stefan for info. I now understand= what u are=20 doing. The audio amp is convenient for 9 kcs but I will build another= class D=20 for 9 kcs eventually
My 137 amp is class D and 500 is clas= s E all home=20 built.
73 de mal/g3kev
 
----- Original Message -----
Sent: Tuesday, August 17, 201= 0 3:50=20 PM
Subject: Re: LF: Earth electr= odes antenna=20 tests[Contest results]

Mal,

I have a 2 uF C in series to the primary= coil. I am=20 using a homemade H bridge switching mode PA. The circuit is currentl= y just in=20 my mind but maybe i can draw and publish it soon. The impedance leve= l of the=20 primary side is about 150 Ohm.

73, Stefan

Am 17.08.20= 10 16:38,=20 schrieb mal hamilton:=20
Stefan
Are u using an audio amp, if so= do u have a=20 capacitor in series with the link winding otherwise the winding mi= ght appear=20 as an almost short cct because of the low dc resistance.
73 de mal/g3kev
 
-----=20 Original Message -----
Sent:=20 Tuesday, August 17, 2010 12:46 PM
Subject:=20 Re: LF: Earth electrodes antenna tests[Contest results]

Mal,

I am using a galvanic decoupled prima= ry winding=20 at the bottom of the water barrel where the coil is wound on. Ad= just the=20 primary number of turns so that enough power is fed into the sys= tem. Watch=20 the photo on my qrz.com page named "new amperemeter". There you= see the=20 primary winding just above the amperemeter.

73,=20 Stefan


Am 17.08.2010 13:38, schrieb mal hamilton:=20
Stefan
I am talking about matching= the amp 8 ohms=20 to 50 ohms not about resonating the antenna. My antenna is alr= eady=20 resonated for 9 Kcs, or 137 as required.
I was referring to your kite= antenna and=20 what method you used for matching amp to antenna.
de mal/g3kev
 
-----=20 Original Message -----
Sent:=20 Tuesday, August 17, 2010 12:22 PM
Subject:=20 Re: LF: Earth electrodes antenna tests[Contest results]

Mal,

Are you talking about a earth el= ectrode=20 antenna or your vertical antenna? I assume you mean the vert= ical=20 ;-)

You will get several kV, most probably above 10= kV rms on=20 your antenna. That's why a ferrite transformer is not a good= choice=20 for a large ( C ) antenna in addition with QRO! For your 5= W tests it=20 may work with a ferrite coil L but not at 500 W and=20 above.

There is no alternative to wind an air= coil if=20 you want to generate a signal that can be watched in the far= field.=20

And if you want to generate a signal that can be hea= red in CW=20 across EU i recommend a power supply like i had as i worked= in=20 Darmstadt last year: http://www.hst.tu-darmstad= t.de/index.php?id=3D173&L=3D1=20 ;-)

Transforming to 50 Ohm is not wrong but it is not= =20 necessary. You can just resonate the antenna and match the= load to=20 something suitable for the audio amp (4...8 Ohm). A 50 Ohm= impedance=20 level is just necessary if you want to filter your signal wi= th a=20 precise dimensioned low pass filter that properly works at= 50 Ohm=20 input and output impedance (in my opinion). Essential is, th= at the=20 power is pushed into the antenna! ;-)

73, Stefan
<= BR>PS: On=20 an earth antenna, which is not resonated (!), you just have= to apply a=20 proper output voltage to the antenna that causes the DC inpu= t power at=20 the PA that you want to generate.


Am 17.08.2010= 12:51,=20 schrieb mal hamilton:=20 
Stefan
What method do u use to couple the amplifier to the electrodes? Is the=
 amp
output impedence 8 ohms.
My method for my antenna using an audio amp would be to use a ferrite
transformer to step up the 8  ohms to 50 ohms (x 6.250) turns Prim 8=
 and
Secondary 20 turns. This way I can use my existing test equipment for=
 swr
etc.
mal/g3kev

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