X-GM-THRID: 1202122608845734752 X-Gmail-Labels: rsgb lf X-Gmail-Received: 99d0f719591937089c2fe3fcbf98893cfc2a3336 Delivered-To: daveyxm@gmail.com Received: by 10.54.72.15 with SMTP id u15cs34wra; Mon, 1 May 2006 01:15:57 -0700 (PDT) Received: by 10.49.38.13 with SMTP id q13mr79280nfj; Mon, 01 May 2006 01:15:57 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.gmail.com with ESMTP id m16si976515nfc.2006.05.01.01.15.56; Mon, 01 May 2006 01:15:57 -0700 (PDT) Received-SPF: neutral (gmail.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 1FaTXQ-0006aj-6M for rs_out_1@blacksheep.org; Mon, 01 May 2006 09:13:48 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1FaTXP-0006aa-Py for rsgb_lf_group@blacksheep.org; Mon, 01 May 2006 09:13:47 +0100 Received: from outbound02.telus.net ([199.185.220.221] helo=priv-edtnes09.telusplanet.net) by relay1.thorcom.net with esmtp (Exim 4.51) id 1FaVOG-0000zy-09 for rsgb_lf_group@blacksheep.org; Mon, 01 May 2006 11:12:44 +0100 Received: from priv-edtnaa06.telusplanet.net ([64.180.173.28]) by priv-edtnes09.telusplanet.net (InterMail vM.6.01.05.04 201-2131-123-105-20051025) with ESMTP id <20060501081324.KORK26243.priv-edtnes09.telusplanet.net@priv-edtnaa06.telusplanet.net> for ; Mon, 1 May 2006 02:13:24 -0600 Received: from [192.168.1.1] (d64-180-173-28.bchsia.telus.net [64.180.173.28]) by priv-edtnaa06.telusplanet.net (BorderWare MXtreme Infinity Mail Firewall) with ESMTP id 3198XNWKDH for ; Mon, 1 May 2006 02:13:24 -0600 (MDT) Message-ID: <4455C323.6020600@telus.net> Date: Mon, 01 May 2006 01:13:23 -0700 From: Scott Tilley User-Agent: Thunderbird 1.5.0.2 (Windows/20060308) MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <3e6.11ff519.31871463@aol.com> In-Reply-To: <3e6.11ff519.31871463@aol.com> X-Spam-Score: -0.7 (/) X-Spam-Report: autolearn=disabled,AWL=-1.240,FORGED_RCVD_HELO=0.05,FROM_ENDS_IN_NUMS=0.516 Subject: Re: LF: RE: pictures of my new 136kHz stn Content-Type: text/plain; charset=ISO-8859-1; 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=1.9 required=5.0 tests=FROM_ENDS_IN_NUMS, MAILTO_TO_SPAM_ADDR 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: 5682 Dick, Dave and LF Group Using a design here with 4 FETs (W34NB20) in a module with the two pairs combined this nets about 900W with 37V input. Now on the MO_ALFA we have 8 FETs in two modules of 4 arranged in pairs of 2 combined for 2KW and when loafing on the 'stun' setting we're able to get 1200W+ without much heating at all, in fact she runs very cool(much more efficient then a single module running balls to the wall)... At 2KW forced air is a must... Nothing paralleled and no traditional LPF required as the Wilkinson does the job and provides some port to port isolation. We could push for maybe 3KW as the 8x400W PSUs are loafing still... But after the Tesla display when we commissioned it at 2KW in my backyard cooler heads prevailed...! The highest voltage we can reliably push out a signal with without 'strange' events is 41V. However, I run lower at 37V as a nominal safe choice. I found the W34NB20 better in my application then the IRFP450... 73 Scott VE7TIL G0MRF@aol.com wrote: > In a message dated 30/04/2006 21:43:09 GMT Standard Time, > ganymede444@btopenworld.com writes: > > Hi Dick, LF Group, > > What power supply voltage will you be using for your new TX, and > what RF power do you hope to get out with 4 times IRFP450? > > 73, Dave G3WCB IO91RM > > Hi Dave / Dick. > > If it helps: I converted on of my 250W linear amplifiers which used 4 > IRFP450s to class D(ish) The power output went to 700W on 136kHz. I > just replaced the input phase splitting transformer with the normal > class D 4426 driver chip. > I also used the same amp in Scotland at 300W on 73kHz to work Jim > M0BMU and Derek G3GRO who were nr Lands End. PSU was adjustable 35 to 48V. > > Thanks > > David G0MRF