Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-de06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 9394E3800009C; Wed, 8 Aug 2012 18:31:49 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SzEmH-0004zR-CG for rs_out_1@blacksheep.org; Wed, 08 Aug 2012 23:30:57 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SzEmG-0004zI-Un for rsgb_lf_group@blacksheep.org; Wed, 08 Aug 2012 23:30:56 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1SzEmF-0003xm-C2 for rsgb_lf_group@blacksheep.org; Wed, 08 Aug 2012 23:30:55 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id q78MUshX029183 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 9 Aug 2012 00:30:54 +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 q78MUs9v007670 for ; Thu, 9 Aug 2012 00:30:54 +0200 Message-ID: <5022E802.30404@iup.uni-heidelberg.de> Date: Thu, 09 Aug 2012 00:28:18 +0200 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: In-Reply-To: X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id q78MUshX029183 X-Spam-Score: -0.7 (/) 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 Dimitris, Am 09.08.2012 00:03, schrieb Dimitrios Tsifakis: > Hello LF group, > > I am building a 200 W Class-E transmitter for LF but keep killing the > capacitors in the output circuit (both C1 and C2 according to the > schematic in Sokal's QST article). I have used a mixture WIMA > polypropylene MKP10, MKP4 and FKP1 caps and I haven't damaged any FKP > ones so far. Should I not bother with MKP and use only FKP caps or is > there any other type of capacitor what will do the job? After all tests i have done with high RF power and caps, i can say that the FKP-1 caps perform excellent. They are cheap and easy available, at least here. I heared much about the silver mica caps but can't find them anywhere. [...] Content analysis details: (-0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [129.206.100.212 listed in list.dnswl.org] -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: 046f068074e745d5c60ca47deee9b503 Subject: Re: LF: Caps for Class-E amp Content-Type: text/plain; charset=ISO-8859-1; 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=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: 0:2:464782528:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d40ce5022e8d53ba9 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hello Dimitris, Am 09.08.2012 00:03, schrieb Dimitrios Tsifakis: > Hello LF group, > > I am building a 200 W Class-E transmitter for LF but keep killing the > capacitors in the output circuit (both C1 and C2 according to the > schematic in Sokal's QST article). I have used a mixture WIMA > polypropylene MKP10, MKP4 and FKP1 caps and I haven't damaged any FKP > ones so far. Should I not bother with MKP and use only FKP caps or is > there any other type of capacitor what will do the job? After all tests i have done with high RF power and caps, i can say that=20 the FKP-1 caps perform excellent. They are cheap and easy available, at=20 least here. I heared much about the silver mica caps but can't find them=20 anywhere. I'm using FKP-1 caps in a 1 kW cl=F6ass E PA running at 80V DC, without=20 any problems! > I need a > couple of hundred of nanofarads. So the supply voltage is 12V? > The voltage rating of the caps I > destroyed was 400 VDC or 250 VAC. I can see that these caps have a > decreasing AC rating as the frequency goes up, but that's what I had > in the junk box at the time... > > The mode of failure of these MKP10 0.1 400 VDC caps is interesting > too, they seem to go down in capacitance as the damage progresses. > =20 Coming from the self healing effect... GL! 73, Stefan/DK7FC > Any advice is appreciated. > > 73, Dimitris VK1SV/SV1DET > =20