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 vAAJfRMF024456 for ; Fri, 10 Nov 2017 20:41:30 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1eDF5l-0003X3-MA for rs_out_1@blacksheep.org; Fri, 10 Nov 2017 19:35:53 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1eDF5k-0003Wu-UQ for rsgb_lf_group@blacksheep.org; Fri, 10 Nov 2017 19:35:52 +0000 Received: from mout02.posteo.de ([185.67.36.66]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1eDF5i-0005A1-Ak for rsgb_lf_group@blacksheep.org; Fri, 10 Nov 2017 19:35:51 +0000 Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id 5AA4A20A9C for ; Fri, 10 Nov 2017 20:35:46 +0100 (CET) Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 3yYVcx3cZ1zytZ for ; Fri, 10 Nov 2017 20:35:45 +0100 (CET) Message-ID: <5A05FF90.6000106@posteo.de> Date: Fri, 10 Nov 2017 20:35:44 +0100 From: DK7FC 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: <22d6c712-43af-3a5d-099e-adb285f086a1@n1bug.com> <7d1279b6d1a84b692d281d48901f2b23@xs4all.nl> <5A03089B.6060600@posteo.de> In-Reply-To: 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: Am 10.11.2017 19:44, schrieb N1BUG: > I see a nice clean sine wave at the other side of the LPF. With a good LPF, the output often looks quite good on a scope, even with massively distorted input signals. > But I see a lot of RF (36 volts peak to peak) at the +13.8V power > connection to the PA! Yes and your power supply doesn't like it, it can be damaged from the high RF peak currents. Or the voltage regulator can do crazy things. And BTW the current measurement is likely to be totally wrong with such an AC component. With the coil you can decouple the AC component from the supply, at least most of it. Just take a piece of enameled cu wire, 1mm diameter, and wind a coul with 15 turns on something with 15mm diameter. Or use a T106-2 core for example. Of course the big C is needed as well. For the 1 uF cap i would use WIMA MKP-10 or so. Without calculating i would say that this improves things significantly. [...] Content analysis details: (-0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: 7aa9ad08848e488e22e0ff1d71f4ef1d 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 Am 10.11.2017 19:44, schrieb N1BUG: > I see a nice clean sine wave at the other side of the LPF. With a good LPF, the output often looks quite good on a scope, even with massively distorted input signals. > But I see a lot of RF (36 volts peak to peak) at the +13.8V power > connection to the PA! Yes and your power supply doesn't like it, it can be damaged from the high RF peak currents. Or the voltage regulator can do crazy things. And BTW the current measurement is likely to be totally wrong with such an AC component. With the coil you can decouple the AC component from the supply, at least most of it. Just take a piece of enameled cu wire, 1mm diameter, and wind a coul with 15 turns on something with 15mm diameter. Or use a T106-2 core for example. Of course the big C is needed as well. For the 1 uF cap i would use WIMA MKP-10 or so. Without calculating i would say that this improves things significantly. 73 and have fun, Stefan