Return-Path: Received: from mtain-dg04.r1000.mx.aol.com (mtain-dg04.r1000.mx.aol.com [172.29.65.12]) by air-dd03.mail.aol.com (v129.4) with ESMTP id MAILINDD033-86594d2209eb193; Mon, 03 Jan 2011 12:39:55 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dg04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 37302380000E2; Mon, 3 Jan 2011 12:39:53 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PZoN8-0006E7-Cn for rs_out_1@blacksheep.org; Mon, 03 Jan 2011 17:39:06 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PZoN7-0006Dy-Sf for rsgb_lf_group@blacksheep.org; Mon, 03 Jan 2011 17:39:05 +0000 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PZoN6-0006c0-Kz for rsgb_lf_group@blacksheep.org; Mon, 03 Jan 2011 17:39:05 +0000 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay2.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id p03Hd4FA003057 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 3 Jan 2011 18:39:04 +0100 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id p03Hd4Xd029063 for ; Mon, 3 Jan 2011 18:39:04 +0100 Message-ID: <4D2208ED.8010406@iup.uni-heidelberg.de> Date: Mon, 03 Jan 2011 18:35:41 +0100 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: <4D1B7B17.2040007@iup.uni-heidelberg.de> <775D0BEF3A4B453EA682B574FFDB58E3@lindavideo> In-Reply-To: <775D0BEF3A4B453EA682B574FFDB58E3@lindavideo> X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: DK7FC's VLF Active Antenna Content-Type: multipart/alternative; boundary="------------010307040203040304030804" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_40_50,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: 3039ac1d410c4d2209e90265 X-AOL-IP: 195.171.43.25 X-Mailer: Unknown (No Version) --------------010307040203040304030804 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay2.uni-heidelberg.de id p03Hd4FA003057 Hi Ken, Am 03.01.2011 10:07, schrieb Ken: > Hi Stefan. > I have just completed your VLF Active Antenna except for the 4:1=20 > transformer Fine! You can try to run the antenna without the transformer. Just add=20 it later and see if there is an improvement! Compare it to the antenna=20 you used befor and see if there is a significant difference. Find a=20 suitable location and reduce the mains hum. This is essential for proper= =20 working! > , considering all my previous correspondence regarding sound card=20 > microphone input impedances being anywhere between 4k ohms and 10k=20 > ohms, are you using this as a step - up or step - down transformer, I am using it as a step down transformer. > and which sound card input are you using mic or line input? I only have one input on all the 6 PCs i currently know/use. This is a=20 microphone input i assume. > I will be using Winrad 1.32, and was hoping to complete in order to=20 > look for Chris G3XIZ today as his QTH is 20km from my self. > Wishing you good luck with you sub9kHz work in 2011. TNX! Good luck and all the best for 2011!! 73, Stefan > 73s. > Ken > M0KHW > ----- Original Message ----- > > *From:* Stefan Sch=E4fer > *To:* rsgb_lf_group@blacksheep.org > > *Sent:* Wednesday, December 29, 2010 6:16 PM > *Subject:* Re: LF: DK7FC's VLF Active Antenna > > Hi Ken, > > I have not tested other JFETs so far. Is it just because of the > SMD housing? I don't use a SMD PCB but a "free air" soldering. So > if this is the problem, just solder the FETs legs directly on the > next part, e.g. solder the drain directly on the 390 Ohm resistor. > Attached you find a picture that shows how my current used VLF > grabber antenna looks inside. Don't be shocked ;-) > > If you anyway want an alternative, the _J310_ or the (2SK170) > should be possible. There are some parameters like the noise and > the gain and the input capacitance which are affecting the > performance but this is all not so critical on VLF. > > 73, Stefan/DK7FC > > > > Am 29.12.2010 17:58, schrieb Ken: >> Stefan. >> Could you please recommend an equivalent to to BF862 which is not >> Surface Mount for use in this circuit. >> 73s >> Ken >> M0KHW > --------------010307040203040304030804 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi Ken,

Am 03.01.2011 10:07, schrieb Ken:
Hi Stefan.
I have just completed your VLF Active Antenna except for the 4:1 transformer
Fine! You can try to run the antenna without the transformer. Just add it later and see if there is an improvement! Compare it to the antenna you used befor and see if there is a significant difference. Find a suitable location and reduce the mains hum. This is essential for proper working!
, considering all my previous correspondence regarding sound card microphone input impedances being anywhere between 4k ohms and 10k ohms, are you using this as a step - up or step - down transformer,
I am using it as a step down transformer.
and which sound card input are you using mic or line input?
I only have one input on all the 6 PCs i currently know/use. This is a microphone input i assume.
I will be using Winrad 1.32, and was hoping to complete in order to look for Chris G3XIZ today as his QTH is 20km from my self.
Wishing you good luck with you sub9kHz work in 2011.
TNX! Good luck and all the best for 2011!!

73, Stefan
 
73s.
Ken
M0KHW
 
----- Original Message -----
Sent: Wednesday, December 29, 2010 6:16 PM
Subject: Re: LF: DK7FC's VLF Active Antenna

Hi Ken,

I have not tested other JFETs so far. Is it just because of the SMD housing? I don't use a SMD PCB but a "free air" soldering. So if this is the problem, just solder the FETs legs directly on the next part, e.g. solder the drain directly on the 390 Ohm resistor. Attached you find a picture that shows how my current used VLF grabber antenna looks inside. Don't be shocked ;-)

If you anyway want an alternative, the J310 or the (2SK170) should be possible. There are some parameters like the noise and the gain and the input capacitance which are affecting the performance but this is all not so critical on VLF.

73, Stefan/DK7FC



Am 29.12.2010 17:58, schrieb Ken:
Stefan.
Could you please recommend an equivalent to to BF862 which is not Surface Mount for use in this circuit.
73s
Ken
M0KHW
--------------010307040203040304030804--