Return-Path: Received: from mtain-dd01.r1000.mx.aol.com (mtain-dd01.r1000.mx.aol.com [172.29.64.141]) by air-db02.mail.aol.com (v128.3) with ESMTP id MAILINDB024-86964bd5eba89a; Mon, 26 Apr 2010 15:38:16 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dd01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 37CBA380000E2; Mon, 26 Apr 2010 15:38:15 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1O6U7G-0001Et-Hl for rs_out_1@blacksheep.org; Mon, 26 Apr 2010 20:37:14 +0100 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1O6U7G-0001Ek-3i for rsgb_lf_group@blacksheep.org; Mon, 26 Apr 2010 20:37:14 +0100 Received: from smtp-out12.han.skanova.net ([195.67.226.212]) by relay2.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1O6U7C-0004Jo-E6 for rsgb_lf_group@blacksheep.org; Mon, 26 Apr 2010 20:37:13 +0100 Received: from [127.0.0.1] (81.235.167.68) by smtp-out12.han.skanova.net (8.5.114) (authenticated as u33233109) id 4BC6CFA7003E1DD4 for rsgb_lf_group@blacksheep.org; Mon, 26 Apr 2010 21:37:04 +0200 Message-ID: <4BD5EB5E.6070702@telia.com> Date: Mon, 26 Apr 2010 21:37:02 +0200 From: "Johan H. Bodin" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; sv-SE; rv:1.9.1.9) Gecko/20100317 Thunderbird/3.0.4 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4EB4F8217FCC42CAB07AE666A6AB07B8@AGB> In-Reply-To: <4EB4F8217FCC42CAB07AE666A6AB07B8@AGB> X-Spam-Score: 0.9 (/) X-Spam-Report: autolearn=disabled,AWL=-0.570,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Probably not a new question... Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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: 3039ac1d408d4bd5eba73f19 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) Yes, or building a simple "SoftRock style" direct conversion front end and feed the audio to the soundcard for further processing by Winrad or similar software capable of processing I/Q audio. What you need is some kind of preselection filer, a quadrature mixer (half-complex mixer, "Tayloe mixer") and a pair of good audio preamps. The front end LO can be as simple as an XTAL oscillator followed by a 74HC74 that divides the XTAL frequency by 4 and produces the two 0/90 degree clocks needed by the mixer. A 74HC4052 analog switch works quite well as mixer on LF, this one can be clocked by the 'HC74 mentioned above or any other 2-bit synchronous binary counter clocked by fLO*4. The tuning is done in the software. You can find some ideas at http://yu1lm.qrpradio.com or look at Gerald Youngblood's QEX article series "A Software Defined Radio for the masses" http://www.flex-radio.com/News.aspx?topic=publications 73 de Johan SM6LKM Graham skrev 2010-04-26 20:55: > You may be better building a LF convertor ? > > G .. > > *From:* Daniele Tincani > *Sent:* Monday, April 26, 2010 6:23 PM > *To:* rsgb_lf_group@blacksheep.org > *Subject:* LF: Probably not a new question... > > Hi LF, > among the so-called "communications receivers" (0.1-30MHz, all modes, > well-known brands, etc.) in the "< 300 euros" price range (used, of > course :-)), which models have good characteristics at LF frequencies? > Any recommended models (in the same price range) outside of the "comms > receivers" class? > Many thanks for your feedbacks. > Cheers > D. > > >