Return-Path: Received: from mtain-mg07.r1000.mx.aol.com (mtain-mg07.r1000.mx.aol.com [172.29.96.207]) by air-db08.mail.aol.com (v128.1) with ESMTP id MAILINDB082-86224bc71c5a3a0; Thu, 15 Apr 2010 10:02:02 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mg07.r1000.mx.aol.com (Internet Inbound) with ESMTP id 333EC38000084; Thu, 15 Apr 2010 10:01:59 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1O2Pci-0005gr-VE for rs_out_1@blacksheep.org; Thu, 15 Apr 2010 15:00:52 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1O2Pci-0005gi-GK for rsgb_lf_group@blacksheep.org; Thu, 15 Apr 2010 15:00:52 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1O2Pch-0002Qb-Jv for rsgb_lf_group@blacksheep.org; Thu, 15 Apr 2010 15:00:52 +0100 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 o3FE0i2f020675 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 15 Apr 2010 16:00:45 +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 o3FE0onh032664 for ; Thu, 15 Apr 2010 16:00:50 +0200 Message-ID: <4BC71C8D.1000508@iup.uni-heidelberg.de> Date: Thu, 15 Apr 2010 16:02:53 +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: <4D95FB39404AA04CA998E7F63B1A2E5F0432C756@esealmw110.eemea.ericsson.se> In-Reply-To: <4D95FB39404AA04CA998E7F63B1A2E5F0432C756@esealmw110.eemea.ericsson.se> X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Amplifier required for LF DX/weak signals? Content-Type: multipart/alternative; boundary="------------030200040403000503010805" 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: 3039ac1d60cf4bc71c576f72 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --------------030200040403000503010805 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hi Daniele, I mean, it depends on the surroundings and the space you have for an (RX) antenna. If you live in the nature, e.g. in a farmers house without electrical energy except a solar panel, battery and your RX a loop is a good choice. If you live in a noisy city without much space for big antennas and without the chance to get a good distance to all cables and QRM sources, a tiny active E-field antenna, as high as possible above the roof of your house will probably work better. Generally, each amplifier has its own noise level and may even decrease the SNR if not well dimensioned. Normally, each ham QTH is something between perfect and miserable, so in many cases experimenting makes sense :-) There are several LFers with passive RX antennas and very good reception possibilities! 73, Stefan/DK7FC Am 15.04.2010 15:26, schrieb Daniele Tincani: > > Hi LF, > > Quite a general question: is a pre-amplifier needed in your opinion > for listening to LF weak signals (e.g. NDB DX, etc.)? > > I read different opinions in very famous articles on the Web: one > opinion is that a bigger non-amplified loop is better than a smaller > amplified loop and an amplifier should be used only if really > necessary (and only with the strictly required gain). On the contrary, > another famous article says that an antenna pre-amplifier is important > for NDB DX, despite it mentions quite a big loop as the antenna. I'm > just a beginner in LF and NDB listening with quite a simple system. I > tried an homebrew amplifier together with my small loop and it seemed > to me that it did not add anything but loudness to both the signal and > the noise. Basically, no improvements in signal readability. What's > your opinion, in particular when cheap portables (e.g. DE1103) are > involved? > > Best regards > > Daniele > --------------030200040403000503010805 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi Daniele,

I mean, it depends on the surroundings and the space you have for an (RX) antenna. If you live in the nature, e.g. in a farmers house without electrical energy except a solar panel, battery and your RX a loop is a good choice. If you live in a noisy city without much space for big antennas and without the chance to get a good distance to all cables and QRM sources, a tiny active E-field antenna, as high as possible above the roof of your house will probably work better.
Generally, each amplifier has its own noise level and may even decrease the SNR if not well dimensioned.
Normally, each ham QTH is something between perfect and miserable, so in many cases experimenting makes sense :-) There are several LFers with passive RX antennas and very good reception possibilities!

73, Stefan/DK7FC


Am 15.04.2010 15:26, schrieb Daniele Tincani:

Hi LF,

 

Quite a general question: is a pre-amplifier needed in your opinion for listening to LF weak signals (e.g. NDB DX, etc.)?

I read different opinions in very famous articles on the Web: one opinion is that a bigger non-amplified loop is better than a smaller amplified loop and an amplifier should be used only if really necessary (and only with the strictly required gain). On the contrary, another famous article says that an antenna pre-amplifier is important for NDB DX, despite it mentions quite a big loop as the antenna. I’m just a beginner in LF and NDB listening with quite a simple system. I tried an homebrew amplifier together with my small loop and it seemed to me that it did not add anything but loudness to both the signal and the noise. Basically, no improvements in signal readability. What’s your opinion, in particular when cheap portables (e.g. DE1103) are involved?

 

Best regards

Daniele

 

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