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 vAAM2JAw024854 for ; Fri, 10 Nov 2017 23:02:20 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1eDHJX-0003wd-Rx for rs_out_1@blacksheep.org; Fri, 10 Nov 2017 21:58:15 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1eDHJX-0003wT-Ih for rsgb_lf_group@blacksheep.org; Fri, 10 Nov 2017 21:58:15 +0000 Received: from mout.perfora.net ([74.208.4.196]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1eDHJT-0005o6-KC for rsgb_lf_group@blacksheep.org; Fri, 10 Nov 2017 21:58:14 +0000 Received: from [192.168.1.125] ([72.224.254.201]) by mrelay.perfora.net (mreueus002 [74.208.5.2]) with ESMTPA (Nemesis) id 0MC2JK-1eM2jo3eyG-008rXy for ; Fri, 10 Nov 2017 22:58:09 +0100 To: rsgb_lf_group@blacksheep.org References: <22d6c712-43af-3a5d-099e-adb285f086a1@n1bug.com> <7d1279b6d1a84b692d281d48901f2b23@xs4all.nl> <5A03089B.6060600@posteo.de> <1510345776321.99412@kuleuven.be> From: N1BUG Message-ID: Date: Fri, 10 Nov 2017 16:58:07 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1510345776321.99412@kuleuven.be> Content-Language: en-US X-Provags-ID: V03:K0:IP1elVt93y8irfbwCNREX5/lxpR7U8oWXEbsV7agtr8Ojf49FPT Ce14jAYIySCNAqdC9pmMN/J4G8/7/QOlxMIDfU674zPmxhgZi3JqqCFTKkdYjPDsJXIIlzH WSNErar7dKqBrDPcoKwL6UDoxgPR1vA11UNaI8vhf4O4RkGmJG4dNQfJhcnlQpKCd3xRX0E nPtmkyzyQZD5jdtGTKGSA== X-UI-Out-Filterresults: notjunk:1;V01:K0:m7tuSLDftEw=:BwzmhIUOlhWvW+LBnZmPnY LYywU8nOc7OV3i1BCaF3YEWwJ3yTLy9UetUWkUhIwKspA4MLwOgOaonWVbyGWco6zZ0OMr1HK +OL/IMZXLGj/ofK8q4RfXowl5obKwMq6NVv7wX73zTPdlOkkmn8RjUytxpQ2WOr8E2pvaIL4p bMJ+TvFcES6hvv+aUo1iRNB7uHKHImlUfERpjv5ctdnXzwOD4ekerofiKZtNAvJv03PCyfQL7 P+T6BiIKLdPNWFLBA4CU5NfrIfHYcWKoh2lDgaAzxJxUex8TcwCA2Be3TubwARrDugIV+OWRu pDSrX+nztqQqJyyry/wWIK9IQZOk6kF05YELBy00/bkb+7RKnk3XWy/iAGxIXxKCSkzTGdFPV 4rJ5Ufv//7DMsTaSp3CvmPglGZ5MoL8xf53LsksfeOmBKtxRWlJNh2aHK/IfOaAqO+GZ0BFj9 +nW0I6JIMHK0rpo2qFWMuhshiuAv89IrUiXqyEd6dO6xZ2CSTNaeQmhw3sFuVq5uvvh1eGDjU 6zBoKd2SW/Z4cNwzu/3vOw9TCFpD94mO1ryE59lgPe0wu8RZYOWcJrcftfiAzdEmbG2MDI5Jy 3jJqNVlGgMvIhPmHF/5ZKfeiLDmh+Yh5SvuGiS9DeRlEcjRVgBshDtb01oiKP6uJFeNliy70x KSQ877TyqnGRi9ClQyVfSC7SH/8XkGV8ZzTSlPma50RsRmiKNMsDQw57MiRjYe4y2cXrK7Sx4 uHptRvAtum7neN3S5YJ0wUPj+wMu6zdG3NuevDeWej2OjigTvNLOLnhpmi4= X-Spam-Score: 0.0 (/) 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: Hello Rik, Thanks for the good suggestion. I tried it on a battery removed from my lawn mower. I won't be needing the lawn mower for some months! Running it from the battery does not significantly reduce the RF I see on the amplifier +DC input lead. I can clean it up (mostly) by putting a 100 uF bypass capacitor at that point. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- X-Scan-Signature: e90dcb17768c7e768f13e0721cc1c0c7 Subject: Re: LF: PA problem 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 Hello Rik, Thanks for the good suggestion. I tried it on a battery removed from my lawn mower. I won't be needing the lawn mower for some months! Running it from the battery does not significantly reduce the RF I see on the amplifier +DC input lead. I can clean it up (mostly) by putting a 100 uF bypass capacitor at that point. 73, Paul N1BUG On 11/10/2017 03:30 PM, Rik Strobbe wrote: > Hello Paul, > > I just had a look at the circuit (http://qrp-labs.com/ultimate3/u3mods/lfamp.html). > One end of the output transformer connected is to the +13.8V should be "cold" (no RF). > As already mentioned regulated power supplies often behave strange to reverse (RF) currents. > To rule out any hickups of the power supply I would suggest to run the PA on a large (car) battery or an unregulated power supply (just transformer + rectifier + large C of at least 10000uF). Now the voltage at one end of the output transformer should be (almost) pure DC. > If the PA run fine (expected output power and efficiency) now you should focus on AC decoupling the power supply (proper shoke with serveral uF of good caps at both ends). > > 73, Rik ON7YD - OR7T