Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id x1PGN7SZ024986 for ; Mon, 25 Feb 2019 17:23:08 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1gyIvS-0003Z0-44 for rs_out_1@blacksheep.org; Mon, 25 Feb 2019 16:16:18 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1gyIt0-0003Yn-59 for rsgb_lf_group@blacksheep.org; Mon, 25 Feb 2019 16:13:46 +0000 Received: from 576e.8172.0000.0000.0210.4001.0d0f.7062.ip6.static.sl-reverse.com ([2607:f0d0:1004:120::2718:e675] helo=mx1.lylix.net) by relay1.thorcom.net with esmtp (Exim 4.91) (envelope-from ) id 1gyIss-0006Jo-LR for rsgb_lf_group@blacksheep.org; Mon, 25 Feb 2019 16:13:40 +0000 Received: from no3m.local (dynamic-acs-24-144-206-160.zoominternet.net [24.144.206.160]) (Authenticated sender: eric@lylix.net) by mx1.lylix.net (Postfix) with ESMTPSA id A7D131A4000D for ; Mon, 25 Feb 2019 11:13:35 -0500 (EST) To: rsgb_lf_group@blacksheep.org References: <043bec62-8144-5ff3-98a6-9f04699f6a4c@no3m.net> <5C73F86B.8080201@posteo.de> <1551107358099.3307@kuleuven.be> <1516612920.20190225154808@gmail.com> From: Eric NO3M Message-ID: <363e53a6-6235-9041-6db2-c9c163bb3df3@no3m.net> Date: Mon, 25 Feb 2019 11:13:34 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.3 MIME-Version: 1.0 In-Reply-To: <1516612920.20190225154808@gmail.com> Content-Language: en-US X-Spam-Score: 2.0 (++) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Chris, et.al. N1BUG relayed the same information regarding the U3S and class-D amp behavior, so your observation is not a one off... > > I have a series of scope captures from my W1VD amp showing huge > voltage spikes on the FET drains at the end of WSPR and especially > OPERA TX sequences. I suspected inductance was the cause. In [...] Content analysis details: (2.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record 2.0 KHOP_DYNAMIC Relay looks like a dynamic address X-Scan-Signature: 0b2d339ae1d48966556dfb6ad64e2bce Subject: Re: LF: Class D current spikes Content-Type: text/plain; charset=utf-8; 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 Chris, et.al. N1BUG relayed the same information regarding the U3S and class-D amp behavior, so your observation is not a one off... > > I have a series of scope captures from my W1VD amp showing huge > voltage spikes on the FET drains at the end of WSPR and especially > OPERA TX sequences. I suspected inductance was the cause. In fact I > try not use OPERA at high power as i am pretty sure to kill a FET > after a few sessions... Oddly (although I hope msomeone more > knowlegeable has the answer), using WSPR from my U3S direct from CLK0 > of th Si535a or whatever it is never causes these spikes... Or at > least they are well contained. >