Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-df06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 76D46380004EA; Tue, 11 Oct 2011 19:06:35 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1RDlNx-0007gv-7p for rs_out_1@blacksheep.org; Wed, 12 Oct 2011 00:05:21 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1RDlNw-0007gm-LR for rsgb_lf_group@blacksheep.org; Wed, 12 Oct 2011 00:05:20 +0100 Received: from nina.ucs.mun.ca ([134.153.232.76]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from <jcraig@mun.ca>) id 1RDlNu-000104-AP for rsgb_lf_group@blacksheep.org; Wed, 12 Oct 2011 00:05:20 +0100 Received: from plato.ucs.mun.ca (plato.ucs.mun.ca [134.153.232.153]) by nina.ucs.mun.ca (8.13.1/8.13.1) with ESMTP id p9BN5ARb032296 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for <rsgb_lf_group@blacksheep.org>; Tue, 11 Oct 2011 20:35:10 -0230 Date: Tue, 11 Oct 2011 20:35:10 -0230 (NDT) From: jcraig@mun.ca X-X-Sender: jcraig@plato.ucs.mun.ca To: rsgb_lf_group@blacksheep.org In-Reply-To: <C141E3F03F9B47FA80F4461CE4B174BC@AGB> Message-ID: <Pine.LNX.4.64.1110112017160.16796@plato.ucs.mun.ca> References: <4E91694C.8060900@orange.fr> <4E9169AD.8090609@wanadoo.fr> <4E918C0E.30401@freenet.de> <4E918FF1.1010407@iup.uni-heidelberg.de> <1318166502.15085.YahooMailNeo@web28106.mail.ukl.yahoo.com> <1849736542-1318171189-cardhu_decombobulator_blackberry.rim.net-208700020-@b1.c11.bise7.blackberry> <FB0006513E634A96AFED8066F7C344C1@JimPC> <4E920BBA.9040200@iup.uni-heidelberg.de> <BA4122BA92D44641A1BE5ED27FD763E5@JimPC> <Pine.LNX.4.64.1110091918360.28918@plato.ucs.mun.ca> <4E934A40.9040204@gmx.de> <Pine.LNX.4.64.1110102003170.6615@plato.ucs.mun.ca> <006c01cc87ab$427234c0$4001a8c0@lark> <Pine.LNX.4.64.1110102222310.10824@plato.ucs.mun.ca> <834DCCD1D3834F4CB4C171B7C30E85B4@AGB> <004801cc8809$63378d50$4001a8c0@lark> <C141E3F03F9B47FA80F4461CE4B174BC@AGB> MIME-Version: 1.0 X-MUN-Disclaimer: http://www.mun.ca/cc/policies/elect_communications_disclaimer_2011.php X-Spam-Score: 0.6 (/) X-Spam-Report: autolearn=disabled,NO_REAL_NAME=0.55 Subject: Re: LF: VX9MRC QRV 507.77 kHz/ Arcing relays &c. Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed 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=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 x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:496342752:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d40da4e94cbfb51aa X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Dear Group, I'd like to thank all those who sent their ideas. DK7FC suggested shunting the LF tuning coil with a series resonant LC, but ON7YD said it could affect bandwidth on 160m. Stefan wondered where the 50 kV was coming from. That was an upper limit guess based on modelling a short monopole. 1000 watts at 50 ohms is 4.47 amps. Feeding this into 3 mH (X=2500 ohm at 137.8 kHz) gives 11.2 kV (17 kV peak) so relays in series as suggested by G8FZK and G3NYK should work well. Alan's idea of 'mechanical amplification' had cross my mind too! I'm puzzled by the 6pf/metre rule for monoploes. It seems the capacitance of the monopole is much higher. Perhaps I've erred again! Please feel free to critique my silly calculations above. The 8 WPM beacon is running on 507.77 kHz now with 80 watts to a vertical located at GN37. 73 and thanks Joe This electronic communication is governed by the terms and conditions at http://www.mun.ca/cc/policies/electronic_communications_disclaimer_2011.php