Return-Path: Received: (qmail 8510 invoked from network); 15 Dec 2000 12:27:07 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by 10.226.25.101 with SMTP; 15 Dec 2000 12:27:07 -0000 Received: (qmail 18946 invoked from network); 15 Dec 2000 12:30:09 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 15 Dec 2000 12:30:09 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #1) id 146tqD-0003kG-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 15 Dec 2000 12:20:01 +0000 Received: from fep04.swip.net ([130.244.199.132] helo=fep04-svc.swip.net) by post.thorcom.com with esmtp (Exim 3.16 #1) id 146tqC-0003jo-00 for rsgb_lf_group@blacksheep.org; Fri, 15 Dec 2000 12:20:00 +0000 Received: from oemcomputer ([212.151.103.204]) by fep04-svc.swip.net (InterMail vM.5.01.01.01 201-252-104) with SMTP id <20001215121940.NGGP12128.fep04-svc.swip.net@oemcomputer> for ; Fri, 15 Dec 2000 13:19:40 +0100 Message-ID: <00b801c06691$60a82fe0$ee1197d4@oemcomputer> From: "Johan Bodin" To: rsgb_lf_group@blacksheep.org Subject: SV: LF: PSK sidebands Date: Fri, 15 Dec 2000 13:20:13 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi All, >Class C, D, and E amplifiers are not that hard to modulate. Rather than do >anything so drastic as tinkering with PWM in the RF driver stages, apply PWM >methods to the power supply for the final! Yes! I have tried this with PSK31 (at QRP level) and it works very well. I got my inspiration from Clint Turner and his beacon: http://www.ussc.com/~turner/psk_transmitter.html At higher power levels, more attention must be paid to reduction of sidebands from the finite resolution of the PWM and of course the PWM frequency itself. Good luck with your 340V PWM modulator Andy! Perhaps the explosions can be heard here in Sweden? ;-) 73 Johan SM6LKM