Delivered-To: daveyxm@virginmedia.com Received: by 10.50.237.98 with SMTP id vb2csp94642igc; Sun, 19 Jan 2014 13:51:42 -0800 (PST) X-Received: by 10.180.93.196 with SMTP id cw4mr7301782wib.39.1390168301806; Sun, 19 Jan 2014 13:51:41 -0800 (PST) Return-Path: Received: from post.thorcom.com (post.thorcom.com. [195.171.43.25]) by mx.google.com with ESMTP id as2si13456578wjc.137.2014.01.19.13.51.41 for ; Sun, 19 Jan 2014 13:51:41 -0800 (PST) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1W4zon-0005xp-V1 for rs_out_1@blacksheep.org; Sun, 19 Jan 2014 21:22:09 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1W4zon-0005xg-Ef for rsgb_lf_group@blacksheep.org; Sun, 19 Jan 2014 21:22:09 +0000 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1W4zok-0000Kb-W9 for rsgb_lf_group@blacksheep.org; Sun, 19 Jan 2014 21:22:08 +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 s0JLM6bs007730 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 19 Jan 2014 22:22:06 +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 s0JLM696025909 for ; Sun, 19 Jan 2014 22:22:06 +0100 Message-ID: <52DC41F9.7010404@iup.uni-heidelberg.de> Date: Sun, 19 Jan 2014 22:22:01 +0100 From: =?ISO-8859-15?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: <52DBC972.8080200@freenet.de> In-Reply-To: <52DBC972.8080200@freenet.de> X-Spam-Score: -2.8 (--) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Wolf, Thanks, very interesting. Aaah, actually i should finish other projects before starting a new one, but this time it may actually become a short new project ;-) I will try something similar as well :-) An analog filter (without a PC) will allow full-BK CW operation :-) [...] Content analysis details: (-2.8 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [129.206.210.211 listed in list.dnswl.org] -0.5 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: b77892ad90d0261eaf071f4f6cf31464 Subject: Re: LF: 'Ugly weekender' build: passive CW audio filter, used on MF Content-Type: text/plain; charset=ISO-8859-15; format=flowed 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 Hello Wolf, Thanks, very interesting. Aaah, actually i should finish other projects before starting a new one, but this time it may actually become a short new project ;-) I will try something similar as well :-) An analog filter (without a PC) will allow full-BK CW operation :-) 73, Stefan/DK7FC Am 19.01.2014 13:47, schrieb wolf_dl4yhf: > Greetings all, > > I took the opportunity yesterday evening (with lots of stations > crowded within a few hundred Hertz on MF) to test this ridiculously > simple "passive narrow-band audio filter" on air (between RX and > headphone) : > > http://www.qsl.net/dl4yhf/passive_lc_audio_filter/passive_lc_cw_audio_filter.htm > > > (just two LC resonators, one of them adjustable with a 'hex' rotary > switch ie 16 different selectable center frequencies). > > The results were quite stunning, compared with a long FIR filter > (implemented in software), this ugly design helped a lot in the QRM / > QRN .. less 'ringing' than expected from such a simple circuit. > > > 73, > Wolf DL4YHF .