Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mb05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 91B5A3800009E; Mon, 12 Nov 2012 10:03:58 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TXvX0-0006YF-4t for rs_out_1@blacksheep.org; Mon, 12 Nov 2012 15:02:34 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TXvWz-0006Y5-MI for rsgb_lf_group@blacksheep.org; Mon, 12 Nov 2012 15:02:33 +0000 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 1TXvWq-0005q7-KE for rsgb_lf_group@blacksheep.org; Mon, 12 Nov 2012 15:02:32 +0000 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 qACF2M8p021600 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 12 Nov 2012 16:02:23 +0100 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 qACF2MDi015430 for ; Mon, 12 Nov 2012 16:02:22 +0100 Message-ID: <50A10F79.7080806@iup.uni-heidelberg.de> Date: Mon, 12 Nov 2012 16:02:17 +0100 From: =?ISO-8859-1?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 References: <3816C61C35B545F7A7A7E8A1BD2A7CAF@GaryAsus> In-Reply-To: X-Spam-Score: -1.2 (-) 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: Hello Joe (VO1NA), If you're doing modifications on your PA FETs, try the IXDD614CI MOSFET driver. I can assure you that gate drive problems are gone then! I use a single IXDD614CI to drive 4x IRFP260N (gates in parallel) in a 1820 kHz class E PA without any problem :-) [...] Content analysis details: (-1.2 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] -0.2 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message 1.3 GAPPY_SUBJECT Subject: contains G.a.p.p.y-T.e.x.t X-Scan-Signature: e4d79cc1e5beb0f7c63f6aa3ce129e10 Subject: Re: [O_P_E_R_A_] Re: LF: VO1NA OP32 137.777 kHz Content-Type: multipart/alternative; boundary="------------050703050605020407020105" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.8 required=5.0 tests=GAPPY_SUBJECT,HTML_20_30, HTML_MESSAGE 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: 3039ac1d601950a10fde3c62 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------050703050605020407020105 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hello Joe (VO1NA), If you're doing modifications on your PA FETs, try the IXDD614CI MOSFET driver. I can assure you that gate drive problems are gone then! I use a single IXDD614CI to drive 4x IRFP260N (gates in parallel) in a 1820 kHz class E PA without any problem :-) 73, Stefan/DK7FC Am 12.11.2012 11:19, schrieb jcraig@mun.ca: > GM Gary and Group, > > Thank-you for the report. The TX was the original 100 watt unit (Jul '05 > QST) somewhat modified. After frying many FETS over the past decade, > a 4427 driver and IRFP260 hexfet was tried. It seems this FET had too > much gate capacitance for the totem pole driver, hence the 4427. The > gate waveform looks a lot better and the heatsink was cool this > morning, presumably > because the RDS was lower than that for the IRF640. > > The Decca is on standby after a heart-breaking experience. More on that > later... > > Thanks to you Gary and the others who operate the grabber services. > > 73 > Joe VO1NA > > > This electronic communication is governed by the terms and conditions at > http://www.mun.ca/cc/policies/electronic_communications_disclaimer_2012.php > --------------050703050605020407020105 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hello Joe (VO1NA),

If you're doing modifications on your PA FETs, try the IXDD614CI MOSFET driver. I can assure you that gate drive problems are gone then! I use a single IXDD614CI to drive 4x IRFP260N (gates in parallel) in a 1820 kHz class E PA without any problem :-)

73, Stefan/DK7FC

Am 12.11.2012 11:19, schrieb jcraig@mun.ca:
GM Gary and Group,

Thank-you for the report.  The TX was the original 100 watt unit (Jul '05
QST) somewhat modified.  After frying many FETS over the past decade, a 4427 driver and IRFP260 hexfet was tried.  It seems this FET had too much gate  capacitance for the totem pole driver, hence the 4427. The gate waveform looks a lot better and the heatsink was cool this morning, presumably
because the RDS was lower than that for the IRF640.

The Decca is on standby after a  heart-breaking experience.  More on that
later...

Thanks to you Gary and the others who operate the grabber services.

73
Joe VO1NA


This electronic communication is governed by the terms and conditions at
http://www.mun.ca/cc/policies/electronic_communications_disclaimer_2012.php
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