Return-Path: Received: (qmail 51844 invoked from network); 2 Mar 2005 10:50:01 -0000 Received: from unknown (HELO ptb-spamcore02.plus.net) (192.168.71.3) by ptb-mailstore02.plus.net with SMTP; 2 Mar 2005 10:50:01 -0000 Received: from mailnull by ptb-spamcore02.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1D6RSS-000LGP-U3 for dave@picks.force9.co.uk; Wed, 02 Mar 2005 10:52:01 +0000 Received: from [192.168.67.2] (helo=ptb-mxcore02.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.32; FreeBSD) id 1D6RSS-000LGM-Qw for dave@picks.force9.co.uk; Wed, 02 Mar 2005 10:52:00 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore02.plus.net with esmtp (Exim) id 1D6RQW-000GhA-ML for dave@picks.force9.co.uk; Wed, 02 Mar 2005 10:50:00 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1D6RQH-0007Lu-Uu for rs_out_1@blacksheep.org; Wed, 02 Mar 2005 10:49:45 +0000 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1D6RQF-0007K5-CO for rsgb_lf_group@blacksheep.org; Wed, 02 Mar 2005 10:49:43 +0000 Received: from smarthost0.mail.uk.easynet.net ([212.135.6.10]) by relay.thorcom.net with esmtp (Exim 4.43) id 1D6RQD-0007ar-HZ for rsgb_lf_group@blacksheep.org; Wed, 02 Mar 2005 10:49:42 +0000 Received: from tnt-1-77.easynet.co.uk ([195.40.206.77] helo=erica) by smarthost0.mail.uk.easynet.net with smtp (Exim 4.10) id 1D6RQ7-0002ul-00 for rsgb_lf_group@blacksheep.org; Wed, 02 Mar 2005 10:49:36 +0000 Message-ID: <000001c51ef7$8f8d88a0$4dce28c3@erica> From: "g3ldo" To: rsgb_lf_group@blacksheep.org References: Date: Tue, 1 Mar 2005 17:57:54 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 X-SPF-Result: relay.thorcom.net: 212.135.6.10 is neither permitted nor denied by domain of ukonline.co.uk X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=failed,none Subject: LF: Re: Big Bad Amps Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.4 required=5.0 tests=DATE_IN_PAST_12_24 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) Dave G3WCB said: > Hi, Scott. > > If you're into Big Bad Amps, you should check out G4FTC's site > http://www.qsl.net/g4ftc/amplifiers/136khz/home.htm He describes a 3kW LF > amp. that uses 8 x IRFP450's in a bridge arrangement. Biggest PA I've seen > so far! The LF Experimenters Source Book (second edition, now out of print), forerunner of The Low Frequency Experimenters Handbook, describes a 3kW transmitter using a QY5-3000A tube in class AB1 with a plate voltage of 4kV. This design by Tony Preedy, G3LNP used hardware from a salvaged Band II TV transmitter. The limiting factor was the power available from a single phase 240VAC supply via a 13 amp socket! Peter G3LDO