Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 2750C380000AA; Tue, 11 Sep 2012 08:04:58 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TBPBp-0008L0-MH for rs_out_1@blacksheep.org; Tue, 11 Sep 2012 13:03:37 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TBPBp-0008Kr-1f for rsgb_lf_group@blacksheep.org; Tue, 11 Sep 2012 13:03:37 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1TBPBn-0006TG-AG for rsgb_lf_group@blacksheep.org; Tue, 11 Sep 2012 13:03:35 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay2.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id q8BC3Y6a007159 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 11 Sep 2012 14:03:34 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id q8BC3YBt020096 for ; Tue, 11 Sep 2012 14:03:34 +0200 Message-ID: <504F27D5.8040305@iup.uni-heidelberg.de> Date: Tue, 11 Sep 2012 14:00:21 +0200 From: =?UTF-8?B?U3RlZmFuIFNjaMOkZmVy?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: In-Reply-To: X-Spam-Score: -2.6 (--) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hi Christian, > -------- Originalnachricht -------- > Betreff: Re: LF: MF PA > Von: "C. Groeger" > An: rsgb_lf_group@blacksheep.org > Cc: > > Hi Stefan, > Thanks for these infos! > This is always helpful because I'm not a really good technican. Everything I built was a mixtiure of my ideas and stuff from the net... > Output power is 100 w, measured with a 100 w bulb, matched to 50 ohms via transformer. Thus efficiency is ok, I think. > The overall setup is: > Vxo/xo 10 mc/10.24 mc, mixer, Fd, > PreDriver 2n2219, Driver irf640, pa 2 x irf 540. > I have attached a foto... > 73, df5qg > [...] Content analysis details: (-2.6 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [129.206.210.211 listed in list.dnswl.org] -0.3 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: a6b6ffaf48fdddf1ed5c25dc4bf03ee1 Subject: Re: LF: MF PA Content-Type: text/plain; charset=UTF-8; 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=0.0 required=5.0 tests=none 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-sid: 3039ac1d600a504f28ea1e31 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hi Christian, > -------- Originalnachricht -------- > Betreff: Re: LF: MF PA > Von: "C. Groeger" > An: rsgb_lf_group@blacksheep.org > Cc: > > Hi Stefan, > Thanks for these infos! > This is always helpful because I'm not a really good technican. Everything I built was a mixtiure of my ideas and stuff from the net... > Output power is 100 w, measured with a 100 w bulb, matched to 50 ohms via transformer. Thus efficiency is ok, I think. > The overall setup is: > Vxo/xo 10 mc/10.24 mc, mixer, Fd, > PreDriver 2n2219, Driver irf640, pa 2 x irf 540. > I have attached a foto... > 73, df5qg > There is no photo attached. Note that attachments on this reflector must not exceed 400 kB (or so). Otherwiese the email is rejected. Better use a dropbox link for large attachments, so people can decide if they want to have a look at it before downloading all the stuff. Well, 100W out at 120W in is 83% efficiency. And 20W losses can't be a problem for 2 TO-220 FETs as long as you use a suitable heat sink and reasonable thermal coupling. But i'm not sure how you measure 100W RF power with a 100W bulb. Is there no reactive component of the impedance of that bulb when running at 475 kHz? Take a look to the gate voltage, be sure that it is a real rectangular wave. Also run the PA in CW-key-down without connecting a load or a low pass filter and check if the output transformer becomes warm or hot. Maybe the core material is not suitable or the number of primary turns is to low? I don't expect overvoltage problems from a 100V FET at 12V DC supply voltage. Just some ideas... 73, Stefan/DK7FC