Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dc01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 119B838000083; Mon, 12 Nov 2012 11:10:04 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TXwYw-0006j3-Pq for rs_out_1@blacksheep.org; Mon, 12 Nov 2012 16:08:38 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TXwYw-0006iu-9r for rsgb_lf_group@blacksheep.org; Mon, 12 Nov 2012 16:08:38 +0000 Received: from nina.ucs.mun.ca ([134.153.232.76]) by relay1.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1TXwYu-00066q-6G for rsgb_lf_group@blacksheep.org; Mon, 12 Nov 2012 16:08:37 +0000 Received: from plato.ucs.mun.ca (plato.ucs.mun.ca [134.153.232.153]) by nina.ucs.mun.ca (8.13.1/8.13.1) with ESMTP id qACG8WXU030662 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 12 Nov 2012 12:38:32 -0330 Date: Mon, 12 Nov 2012 12:38:32 -0330 (NST) From: jcraig@mun.ca X-X-Sender: jcraig@plato.ucs.mun.ca To: rsgb_lf_group@blacksheep.org In-Reply-To: <50A10F79.7080806@iup.uni-heidelberg.de> Message-ID: References: <3816C61C35B545F7A7A7E8A1BD2A7CAF@GaryAsus> <50A10F79.7080806@iup.uni-heidelberg.de> MIME-Version: 1.0 X-MUN-Disclaimer: http://www.mun.ca/cc/policies/elect_communications_disclaimer_2012.php X-Spam-Score: 1.1 (+) 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 Stefan, Thank-you for the tip. The totem pole worked well for me (thanks to Alan G3NYK) but the waveform was a bit mushy and I suspect it may have contributed to the demise of many FETS as a result of operator incompetence (High SWR, etc). [...] Content analysis details: (1.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.2 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 1.3 GAPPY_SUBJECT Subject: contains G.a.p.p.y-T.e.x.t X-Scan-Signature: ac0f6ff1af52b6036ac1f4fe0c2bd52c Subject: Re: [O_P_E_R_A_] Re: LF: VO1NA OP32 137.777 kHz Content-Type: TEXT/PLAIN; charset=X-UNKNOWN; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.6 required=5.0 tests=GAPPY_SUBJECT,NO_REAL_NAME 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: 3039ac1d408150a11f5c5c57 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hi Stefan, Thank-you for the tip. The totem pole worked well for me (thanks to Alan G3NYK) but the waveform was a bit mushy and I suspect it may have contributed to the demise of many FETS as a result of operator incompetence (High SWR, etc). Could you provide more details on your class E for 1820 kHz? Are key-clicks a problem on top band? 73 Joe On Mon, 12 Nov 2012, Stefan Sch=E4fer wrote: > Hello Joe (VO1NA), > > If you're doing modifications on your PA FETs, try the IXDD614CI=20 > MO= SFET=20 > driver. I can assure you that gate drive problems are gone then! I use a= =20 > single IXDD614CI to drive 4x IRFP260N (gates in parallel) in a 1820 kHz c= lass=20 > E PA without any problem :-) > > 73, Stefan/DK7FC > > Am 12.11.2012 11:19, schrieb jcraig@mun.ca: >> GM Gary and Group, >>=20 >> 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= =20 >> 4427 driver and IRFP260 hexfet was tried. It seems this FET had too muc= h=20 >> gate capacitance for the totem pole driver, hence the 4427. The gate=20 >> waveform looks a lot better and the heatsink was cool this morning,=20 >> presumably >> because the RDS was lower than that for the IRF640. >>=20 >> The Decca is on standby after a heart-breaking experience. More on that >> later... >>=20 >> Thanks to you Gary and the others who operate the grabber services. >>=20 >> 73 >> Joe VO1NA >>=20 >>=20 >> This electronic communication is governed by the terms and conditions at >> http://www.mun.ca/cc/policies/electronic_communications_disclaimer_2012.= php=20 > This electronic communication is governed by the terms and conditions at http://www.mun.ca/cc/policies/electronic_communications_disclaimer_2012.php