Return-Path: Received: (qmail 18588 invoked from network); 13 Apr 2001 12:05:44 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 13 Apr 2001 12:05:44 -0000 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit Received: (qmail 25256 invoked from network); 13 Apr 2001 12:05:35 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 13 Apr 2001 12:05:35 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 14o2De-0002FV-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 13 Apr 2001 12:58:30 +0100 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from tele-post-20.mail.demon.net ([194.217.242.20]) by post.thorcom.com with esmtp (Exim 3.16 #2) id 14o2De-0002FQ-00 for rsgb_lf_group@blacksheep.org; Fri, 13 Apr 2001 12:58:30 +0100 Received: from telemetry.demon.co.uk ([194.222.19.114]) by tele-post-20.mail.demon.net with smtp (Exim 2.12 #2) id 14o2DD-0003yY-0K for rsgb_lf_group@blacksheep.org; Fri, 13 Apr 2001 11:58:04 +0000 Message-ID: Date: Fri, 13 Apr 2001 12:56:58 +0100 To: rsgb_lf_group@blacksheep.org From: "Tom Boucher" Subject: LF: Re: Diplexer In-reply-to: <002801c0c37d$cf6365a0$3d44073e@default> MIME-Version: 1.0 X-Mailer: Turnpike (32) Trial Version 3.05 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Thanks Alan for the direct e-mails. I use a driver transformer wound on a chunky ferrite tube with 5 wire ribbon cable, one primary and 4 secondaries, instead of the H bridge driver chip. Seems to work OK although Bob ZL2CA's comments are worth looking into regarding the not-so-good waveform shape but it is running extremely cool at 500/600 watts. Jim, I'm going to try the series resonant tank again without the secondary 'guard' circuit to see what it buys me. I'll let you know when the first set of STW20NB50 FETs blows! Christer tells me that Johan SM6LKM is also building a bridge PA - be interested to know how he gets on. 73, Tom G3OLB.