Return-Path: Received: from mtain-dj07.r1000.mx.aol.com (mtain-dj07.r1000.mail.aol.com [172.19.187.143]) by air-mb07.mail.aol.com (v129.4) with ESMTP id MAILINMB073-a7a34be85633192; Mon, 10 May 2010 14:53:39 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dj07.r1000.mx.aol.com (Internet Inbound) with ESMTP id DC45F380000BF; Mon, 10 May 2010 14:53:37 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OBY5r-0003LJ-Sj for rs_out_1@blacksheep.org; Mon, 10 May 2010 19:52:43 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OBY5r-0003LA-CL for rsgb_lf_group@blacksheep.org; Mon, 10 May 2010 19:52:43 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OBY5q-0007ze-9k for rsgb_lf_group@blacksheep.org; Mon, 10 May 2010 19:52:43 +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 o4AIqSsY004972 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 10 May 2010 20:52:28 +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 o4AIqeoT022875 for ; Mon, 10 May 2010 20:52:40 +0200 Message-ID: <4BE855F1.9050909@iup.uni-heidelberg.de> Date: Mon, 10 May 2010 20:52:33 +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: In-Reply-To: X-Spam-Score: 1.7 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,MAILTO_TO_SPAM_ADDR=0.276,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: RE: 8,97 kHz active antenna circuit and pictures Content-Type: multipart/alternative; boundary="------------070404010203070500040801" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.2 required=5.0 tests=HTML_20_30,HTML_FONTCOLOR_BLUE, HTML_MESSAGE,HTML_TITLE_EMPTY,MAILTO_TO_SPAM_ADDR 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: 3039cdbc9d0c4be856314f12 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --------------070404010203070500040801 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id o4AIqSsY004972 Hello Victor, LF, It took a little bit to reply to your answer. You have been absolutely=20 right! DLF(153kHz) is here just some 10km away and the strong french LF=20 broadcast station on 162kHz has caused the nonlinear working of my first= =20 stage i assume. Yesterday i talked with Markus/DF6NM and he gave me the=20 very useful hint to add a C between drain and gnd of the first stage=20 (what forms a low pass with the drain R). Before some minutes i added a=20 100nF capacitor, so the edge frequency should be about 15kHz. Before=20 that, i have looked on a second experimental active E field antenna how=20 it influences the gain on the dreamers band (almost no difference). But=20 see the S/N improvement NOW on my grabber=20 (http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber.html)!=20 What a big difference!!! :-))))) So happy about that! :-) Tnx to Markus and you, Victor! 73, Stefan/DK7FC PS: I have built a small TX antenna at my new home QTH in Heidelberg.=20 With a TV transformer and my 300W PA (running at 15W DC input) i apply=20 about 2kV rms on a 10m horizontal wire, about 3m above gnd. The distance= =20 to the grabber here is 1,1km. Hopefully i can see something, at least in= =20 DFCW-600... Am 28.04.2010 15:51, schrieb victor13@online.nl: > Hi Stefan, > looks nice but I suspect you have some im problem in your first stage= =20 > because off the strong line at 9 KHz,Maby it's better to use a filter=20 > at the input.... > 73 > Victor > > -----Oorspronkelijk bericht----- > *Van:* Stefan Sch=E4fer > [mailto:owner-rsgb_lf_group@blacksheep.org]*Namens *Stefan Sch=E4fer > *Verzonden:* woensdag 28 april 2010 12:50 > *Aan:* rsgb_lf_group@blacksheep.org > *Onderwerp:* VLF: 8,97 kHz active antenna circuit and pictures > > Dear LF, > > Daniele and others asked for the circuit of my active E field > antenna that i am using for my grabber. Now i have created a pdf > file where you can find the circuit and a picture of the > arrangement and a spectrogram of the currently working circuit. > > http://www.iup.uni-heidelberg.de/schaefer_vlf/8,97kHz%20active%20E%2= 0field%20antenna%20by%20DK7FC.pdf > > So, if you are interested or want to get some ideas for your own > circuit, take a look on it. I hope the link works. > > So, best 73 and maybe cu this evening there, dreamers. > > Stefan/DK7FC > --------------070404010203070500040801 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hello Victor, LF,

It took a little bit to reply to your answer. You have been absolutely right! DLF(153kHz) is here just some 10km away and the strong french LF broadcast station on 162kHz has caused the nonlinear working of my first stage i assume. Yesterday i talked with Markus/DF6NM and he gave me the very useful hint to add a C between drain and gnd of the first stage (what forms a low pass with the drain R). Before some minutes i added a 100nF capacitor, so the edge frequency should be about 15kHz. Before that, i have looked on a second experimental active E field antenna how it influences the gain on the dreamers band (almost no difference). But see the S/N improvement NOW on my grabber (http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber.html)! What a big difference!!! :-)))))
So happy about that! :-)
Tnx to Markus and you, Victor!

73, Stefan/DK7FC

PS: I have built a small TX antenna at my new home QTH in Heidelberg. With a TV transformer and my 300W PA (running at 15W DC input) i apply about 2kV rms on a 10m horizontal wire, about 3m above gnd. The distance to the grabber here is 1,1km. Hopefully i can see something, at least in DFCW-600...




Am 28.04.2010 15:51, schrieb victor13@online.nl:
Hi Stefan,
 
looks nice but I suspect you  have some im problem in your first stage because off the strong line at 9 KHz,Maby it's better to use a filter at the input....
 
73
 
Victor
-----Oorspronkelijk bericht-----
Van: Stefan Schäfer [mailto:owner-rsgb_lf_group@blacksheep.org]Namens Stefan Schäfer
Verzonden: woensdag 28 april 2010 12:50
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: VLF: 8,97 kHz active antenna circuit and pictures

Dear LF,

Daniele and others asked for the circuit of my active E field antenna that i am using for my grabber. Now i have created a pdf file where you can find the circuit and a picture of the arrangement and a spectrogram of the currently working circuit.

http://www.iup.uni-heidelberg.de/schaefer_vlf/8,97kHz%20active%20E%20field%20antenna%20by%20DK7FC.pdf

So, if you are interested or want to get some ideas for your own circuit, take a look on it. I hope the link works.

So, best 73 and maybe cu this evening there, dreamers.

Stefan/DK7FC

--------------070404010203070500040801--