Return-Path: Received: from mtain-dc10.r1000.mx.aol.com (mtain-dc10.r1000.mx.aol.com [172.29.64.138]) by air-df07.mail.aol.com (v128.1) with ESMTP id MAILINDF074-5efd4bc72228171; Thu, 15 Apr 2010 10:26:48 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dc10.r1000.mx.aol.com (Internet Inbound) with ESMTP id 3A6DB38000270; Thu, 15 Apr 2010 10:26:41 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1O2Q0q-0000Kz-2X for rs_out_1@blacksheep.org; Thu, 15 Apr 2010 15:25:48 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1O2Q0p-0000Kq-Hd for rsgb_lf_group@blacksheep.org; Thu, 15 Apr 2010 15:25:47 +0100 Received: from mailgw9.se.ericsson.net ([193.180.251.57]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1O2Q0o-0004Ck-EF for rsgb_lf_group@blacksheep.org; Thu, 15 Apr 2010 15:25:47 +0100 X-AuditID: c1b4fb39-b7b85ae000005cbc-d2-4bc721e96179 Received: from esealmw126.eemea.ericsson.se (Unknown_Domain [153.88.253.124]) by mailgw9.se.ericsson.net (Symantec Brightmail Gateway) with SMTP id F9.96.23740.9E127CB4; Thu, 15 Apr 2010 16:25:45 +0200 (CEST) Received: from esealmw110.eemea.ericsson.se ([153.88.200.78]) by esealmw126.eemea.ericsson.se with Microsoft SMTPSVC(6.0.3790.3959); Thu, 15 Apr 2010 16:25:44 +0200 X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Date: Thu, 15 Apr 2010 16:25:31 +0200 Message-ID: <4D95FB39404AA04CA998E7F63B1A2E5F0432C7CF@esealmw110.eemea.ericsson.se> In-Reply-To: <4BC71C8D.1000508@iup.uni-heidelberg.de> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: LF: Amplifier required for LF DX/weak signals? Thread-Index: AcrcpLy0MgmhRqgDQsaCpgi8OapBlwAAPI7w References: <4D95FB39404AA04CA998E7F63B1A2E5F0432C756@esealmw110.eemea.ericsson.se> <4BC71C8D.1000508@iup.uni-heidelberg.de> From: "Daniele Tincani" To: X-OriginalArrivalTime: 15 Apr 2010 14:25:44.0845 (UTC) FILETIME=[88EE53D0:01CADCA7] X-Brightmail-Tracker: AAAAAA== X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CADCA7.81D5FB2C" Subject: RE: LF: Amplifier required for LF DX/weak signals? X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.3 required=5.0 tests=HTML_50_60, HTML_FONTCOLOR_UNKNOWN,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: 3039ac1d408a4bc7222111b4 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) ------_=_NextPart_001_01CADCA7.81D5FB2C Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Stefan, Understood and I would like to try an active E-probe soon. I also believe= that I have experienced the amusing side of homebrewing enough and now I= think I will choose a more reliable way to get some results, even with le= ss fun :-). So could you kindly suggest any ready-to-use E-probe to buy (a= t a reasonable price)? BTW, any near-future plans for new trials on 9KHz? Cheers D. =20 ________________________________ From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@black= sheep.org] On Behalf Of Stefan Sch=E4fer Sent: gioved=EC 15 aprile 2010 16.03 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Amplifier required for LF DX/weak signals? =20 Hi Daniele,=20 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 elect= rical energy except a solar panel, battery and your RX a loop is a good ch= oice. 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 th= e SNR if not well dimensioned.=20 Normally, each ham QTH is something between perfect and miserable, so in= many cases experimenting makes sense :-) There are several LFers with pas= sive RX antennas and very good reception possibilities! 73, Stefan/DK7FC Am 15.04.2010 15:26, schrieb Daniele Tincani:=20 Hi LF, =20 Quite a general question: is a pre-amplifier needed in your opinion for li= stening 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 lo= op 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 mention= s quite a big loop as the antenna. I'm just a beginner in LF and NDB liste= ning with quite a simple system. I tried an homebrew amplifier together wi= th my small loop and it seemed to me that it did not add anything but loud= ness to both the signal and the noise. Basically, no improvements in signa= l readability. What's your opinion, in particular when cheap portables (e.= g. DE1103) are involved? =20 Best regards Daniele =20 ------_=_NextPart_001_01CADCA7.81D5FB2C Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Hi Stefan,<= /span>

Understood and I would= like to try an active E-probe soon. I also believe that I have experienced the amusing si= de of homebrewing enough and now I think I will choose a more reliable way to ge= t some results, even with less fun J. So could= you kindly suggest any ready-to-use E-probe to buy (at a reasonable price)?

BTW, any near-future= plans for new trials on 9KHz?

Cheers

D.

 

From:= owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Stefan Sch=E4fer
Sent: gioved=EC 15 aprile= 2010 16.03
To: rsgb_lf_group@blackshee= p.org
Subject: Re: LF: Amplifier required for LF DX/weak signals?

 

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 electr= ical 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-fiel= d antenna, as high as possible above the roof of your house will probably wo= rk better.
Generally, each amplifier has its own noise level and may even decrease th= e 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 ver= y 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 nece= ssary (and only with the strictly required gain). On the contrary, another famou= s article says that an antenna pre-amplifier is important for NDB DX, despit= e 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 anythi= ng 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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