Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-md06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 33A1438000089; Wed, 27 Jun 2012 18:36:20 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Sk0pR-0003YX-RI for rs_out_1@blacksheep.org; Wed, 27 Jun 2012 23:35:17 +0100 Received: from [195.171.43.34] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Sk0pR-0003YO-8Y for rsgb_lf_group@blacksheep.org; Wed, 27 Jun 2012 23:35:17 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay2.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1Sk0pO-0001HI-PE for rsgb_lf_group@blacksheep.org; Wed, 27 Jun 2012 23:35:15 +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 q5RMZCtv016722 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 28 Jun 2012 00:35:12 +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 q5RMZClS025405 for ; Thu, 28 Jun 2012 00:35:12 +0200 Message-ID: <4FEB8A2F.3030504@iup.uni-heidelberg.de> Date: Thu, 28 Jun 2012 00:33:19 +0200 From: =?ISO-8859-15?Q?Stefan_Sch=E4fer?= 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 X-Spam-Score: -2.3 (--) X-Spam-Report: Spam detection software, running on the system "relay2.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: MF, For the homebrewers, here is my prototype of a MF class D PA that operates at 12 V DC. Input frequency is divided by 4, so a normal HF TRX can be used (set to 160m / 1.9 MHz) to drive the PA. The input power must not exceed the range of 1...4 watts. The output power can be switched in 2 steps between ~15W and up to 100W, depending on the output impedance and input voltage (10...15V). The output impedance is not so critical, Z=R may be in the range of 30 Ohm to infinity. The FETs are IRFZ48N types, the driver is a ICL7667CPA. The transformer uses RF litz wire, 30x0.1mm diameter. I didn't spend to much effort for optimising the efficiency, not at this power level. During a CW QSO or longer calls at 50 W RF power the heat sink (which is just a 3mm thick Al plate) becomes hand warm. The measured efficiency is 88 % at 18W RF power and 80% at 50W RF power. The needed power for the driver circuitry is included in this measurement. [...] Content analysis details: (-2.3 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] -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: e90dcb17768c7e768f13e0721cc1c0c7 Subject: LF: 472 kHz PA running at 12 VDC Content-Type: text/plain; charset=ISO-8859-15; 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-SCOLL-SCORE: 0:2:443685632:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d605a4feb8ae306b3 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none MF, For the homebrewers, here is my prototype of a MF class D PA that operates at 12 V DC. Input frequency is divided by 4, so a normal HF TRX can be used (set to 160m / 1.9 MHz) to drive the PA. The input power must not exceed the range of 1...4 watts. The output power can be switched in 2 steps between ~15W and up to 100W, depending on the output impedance and input voltage (10...15V). The output impedance is not so critical, Z=R may be in the range of 30 Ohm to infinity. The FETs are IRFZ48N types, the driver is a ICL7667CPA. The transformer uses RF litz wire, 30x0.1mm diameter. I didn't spend to much effort for optimising the efficiency, not at this power level. During a CW QSO or longer calls at 50 W RF power the heat sink (which is just a 3mm thick Al plate) becomes hand warm. The measured efficiency is 88 % at 18W RF power and 80% at 50W RF power. The needed power for the driver circuitry is included in this measurement. If someone is interested i may convert the circuit from my mind into a schematic as a png file. 73, Stefan/DK7FC https://dl.dropbox.com/u/19882028/MF/DK7FC%20472%20kHz%20PA%2015W%2B100W.JPG