Return-Path: Received: (qmail 94628 invoked from network); 28 Aug 2004 17:23:51 -0000 Received: from unknown (HELO ptb-spamcore01.plus.net) (192.168.71.1) by ptb-mailstore01.plus.net with SMTP; 28 Aug 2004 17:23:51 -0000 Received: from mailnull by ptb-spamcore01.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1C171P-000OXg-Al for dave@picks.force9.co.uk; Sat, 28 Aug 2004 18:29:47 +0100 Received: from [192.168.67.1] (helo=ptb-mxcore01.plus.net) by ptb-spamcore01.plus.net with esmtp (Exim 4.32; FreeBSD) id 1C171P-000OXd-7o for dave@picks.force9.co.uk; Sat, 28 Aug 2004 18:29:47 +0100 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim 4.30; FreeBSD) id 1C16ve-000C0b-Pz for dave@picks.force9.co.uk; Sat, 28 Aug 2004 17:23:50 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1C16v0-0004bi-9W for rs_out_1@blacksheep.org; Sat, 28 Aug 2004 18:23:10 +0100 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1C16uz-0004bZ-TO for rsgb_lf_group@blacksheep.org; Sat, 28 Aug 2004 18:23:09 +0100 Received: from cas-mta3-fe.casema.nl ([83.80.1.28] helo=mta.casema.nl) by relay.thorcom.net with esmtp (Exim 4.41) id 1C16ux-0005Co-3x for rsgb_lf_group@blacksheep.org; Sat, 28 Aug 2004 18:23:09 +0100 Received: from pcprive (535582D3.cable.casema.nl [83.85.130.211]) by cas-mta3.mgmt.casema.nl (iPlanet Messaging Server 5.2 HotFix 1.21 (built Sep 8 2003)) with SMTP id <0I3600IFG2YB83@cas-mta3.mgmt.casema.nl> for rsgb_lf_group@blacksheep.org; Sat, 28 Aug 2004 19:22:59 +0200 (CEST) Date: Sat, 28 Aug 2004 19:22:49 +0200 From: haagrimbergen To: rsgb_lf_group@blacksheep.org Message-id: <003401c48d23$a4cd3460$d3825553@pcprive> MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V5.00.2615.200 X-Mailer: Microsoft Outlook Express 5.00.2615.200 X-Priority: 3 X-MSMail-priority: Normal X-SPF-Result: relay.thorcom.net: 83.80.1.28 is neither permitted nor denied by domain of casema.nl X-Spam-Score: 0.5 (/) X-Spam-Report: autolearn=no,HTML_20_30=0.474,HTML_MESSAGE=0.001 Subject: LF: RE key clicks Content-type: text/html; charset=windows-1252 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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-Spam-Filtered: by PlusNet SpamCORE (v3.00) Content-transfer-encoding: 8bit

Dear Jim, LF group,

The average LF aerial together with losses of the tuner coil and ground loss poses a Q of about 100. It means, that after putting RF on the aerial the RF amplitude will rise to 90 percent of its end-value after about 1.6 msec. Also by switching -off RF power 10 percent remains after 1.6 msec.

This gives a ==natural==albeit insufficient limitation of the radiated bandwidth.

By using an active opamp lowpass clickfilter designed for optimally flat phase response with a -3dB cut-off freq. of 25 Hz rise and fall times of about 30msec are obtained. This is pretty well for 15wpm CW speed. With a much smaller bandwidth the signal sounds ==woolly== and is difficult to copy.

The radiated RF bandwidth is then about 160 Hz for keyng components stronger than -40 dB below fundamental.

I think it is good enough for practical use.

73's de Harry, PA0LQ.