Envelope-to: dave@picks.force9.co.uk Delivery-date: Wed, 28 Sep 2005 10:45:03 +0100 Received: by pih-mxcore12.plus.net with spam-scanned (PlusNet MXCore v2.00) id 1EKYUm-0000lp-Gj for dave@picks.force9.co.uk; Wed, 28 Sep 2005 10:45:02 +0100 Received: from post.thorcom.com ([193.82.116.20]) by pih-mxcore12.plus.net with esmtp (PlusNet MXCore v2.00) id 1EKYUl-0000gY-K2 for dave@picks.force9.co.uk; Wed, 28 Sep 2005 10:45:00 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1EKYTd-0004Q5-40 for rs_out_1@blacksheep.org; Wed, 28 Sep 2005 10:43:49 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1EKYTc-0004Pw-M2 for rsgb_lf_group@blacksheep.org; Wed, 28 Sep 2005 10:43:48 +0100 Received: from [194.203.13.70] (helo=viruswall.astrium.eads.net) by relay1.thorcom.net with esmtp (Exim 4.51) id 1EKZ2A-0006m9-C1 for rsgb_lf_group@blacksheep.org; Wed, 28 Sep 2005 11:19:34 +0100 Received: from mms12031.pth.uk.astrium.corp ([194.35.68.222]) by viruswall.astrium.eads.net with InterScan Messaging Security Suite; Wed, 28 Sep 2005 10:43:33 +0100 Received: by mms12031.pth.uk.astrium.corp with Internet Mail Service (5.5.2650.21) id ; Wed, 28 Sep 2005 10:43:35 +0100 Message-ID: From: "OSBORN, Chris" To: "LF Group (E-mail)" Date: Wed, 28 Sep 2005 10:43:34 +0100 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Subject: LF: Advice will be gratefully received Content-Type: text/plain; charset=iso-8859-1; format=flowed 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-PN-SpamFiltered: by PlusNet MXCore (v2.00) Content-transfer-encoding: 8bit The PA FET's in my new home brew transmitter keep exploding ! I'm using push-pull IRF520's rated at 100 V Vds and my supply is 30 volts. I am careful not to exceed the V gs. The gates are driven with a toroidal transformer and the whole circuit is just a scaled up version of my original TX, which works fine. It generates healthy power into a 50 ohm dummy load but on connection to the aerial circuit - bang ! The aerial system is identical to that used with the old TX ! Has anyone any ideas on what's causing the problem and how to cure it ? I'm running out of FET's and my nerves are somewhat frayed (shell shock!) 73 Chris G3XIZ This email is for the intended addressee only. If you have received it in error then you must not use, retain, disseminate or otherwise deal with it. Please notify the sender by return email. The views of the author may not necessarily constitute the views of EADS Astrium Limited. Nothing in this email shall bind EADS Astrium Limited in any contract or obligation. EADS Astrium Limited, Registered in England and Wales No. 2449259 Registered Office: Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2AS, England