X-GM-THRID: 1232930756099789616 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.115.73.3 with SMTP id a3cs293877wal; Thu, 5 Apr 2007 16:06:36 -0700 (PDT) Received: by 10.67.29.12 with SMTP id g12mr2522493ugj.1175814395959; Thu, 05 Apr 2007 16:06:35 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id j3si3362412ugd.2007.04.05.16.06.32; Thu, 05 Apr 2007 16:06:35 -0700 (PDT) Received-SPF: neutral (google.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1HZayR-00012x-HX for rs_out_1@blacksheep.org; Fri, 06 Apr 2007 00:02:35 +0100 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1HZayR-00012o-1F for rsgb_lf_group@blacksheep.org; Fri, 06 Apr 2007 00:02:35 +0100 Received: from imo-d21.mx.aol.com ([205.188.144.207]) by relay2.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1HZayP-0007Fy-1U for rsgb_lf_group@blacksheep.org; Fri, 06 Apr 2007 00:02:34 +0100 Received: from G0MRF@aol.com by imo-d21.mx.aol.com (mail_out_v38_r8.1.) id l.cf4.9ea6232 (40520) for ; Thu, 5 Apr 2007 19:02:21 -0400 (EDT) From: G0MRF@aol.com Message-ID: Date: Thu, 5 Apr 2007 19:02:21 EDT To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 X-Mailer: 9.0 SE for Windows sub 5014 X-Spam-Flag: NO X-Spam-Score: -0.2 (/) X-Spam-Report: autolearn=disabled,AWL=-0.763,HTML_MESSAGE=0.001,NO_REAL_NAME=0.55 Subject: LF: [500] Low pass filtering Content-Type: multipart/alternative; boundary="-----------------------------1175814140" 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_40_50,HTML_MESSAGE, NO_REAL_NAME 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 Status: O X-Status: X-Keywords: X-UID: 5362 -------------------------------1175814140 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Hi all. I've had a couple of mails asking about harmonic filters for 500kHz transmitters. I sat down today and built a 7 element Chebyshev low pass. It seems quite forgiving on components and gives -41dB at 2nd harmonic and -66dB at the third. Details at: _www.g0mrf.freeserve.co.uk/lpf.htm_ (http://www.g0mrf.freeserve.co.uk/lpf.htm) Thanks David G0MRF -------------------------------1175814140 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Hi all.

I've had a couple of mails asking about harmonic filters for 500kHz=20 transmitters.

I sat down today and built a 7 element Chebyshev low pass.

It seems quite forgiving on components and gives -41dB at 2nd harmonic=20= and=20 -66dB at the third.

Details at: www.g0mrf.freeserve.co.uk/= lpf.htm

Thanks

David G0MRF

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