Return-Path: Received: (qmail 6224 invoked from network); 23 Jan 2004 16:45:53 -0000 Received: from unknown (HELO ptb-mxscan01.plus.net) (212.159.14.235) by ptb-mailstore02.plus.net with SMTP; 23 Jan 2004 16:45:53 -0000 Received: (qmail 12718 invoked from network); 23 Jan 2004 16:45:53 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from ptb-mxcore01.plus.net (212.159.14.215) by ptb-mxscan01.plus.net with SMTP; 23 Jan 2004 16:45:46 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim) id 1Ak4RF-0002r6-JZ for dave@picks.force9.co.uk; Fri, 23 Jan 2004 16:45:45 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Ak4Po-00084K-9g for rs_out@blacksheep.org; Fri, 23 Jan 2004 16:44:16 +0000 Received: from [62.253.164.44] (helo=mta4-svc.business.ntl.com) by post.thorcom.com with esmtp (Exim 4.14) id 1Ak4Pn-00084B-LF for rsgb_lf_group@blacksheep.org; Fri, 23 Jan 2004 16:44:15 +0000 X-Fake-Domain: l8p8y6 Received: from l8p8y6 ([62.252.229.64]) by mta4-svc.business.ntl.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with SMTP id <20040123164413.JYCO13664.mta4-svc.business.ntl.com@l8p8y6> for ; Fri, 23 Jan 2004 16:44:13 +0000 X-Bad-Message-ID: no DNS (l8p8y6) Message-ID: <000201c3e18c$03c4b540$40e5fc3e@l8p8y6> From: "hamilton mal" To: rsgb_lf_group@blacksheep.org References: <000c01c3e02e$600a21a0$01eafc3e@l8p8y6> <001501c3e058$ba617980$2102000a@ibm> <002501c3e121$12a54fe0$2102000a@ibm> Date: Fri, 23 Jan 2004 03:54:33 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4807.1700 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: LF: Re: 136kHz project cancelled Content-Type: text/html; charset=windows-1252 X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.9 required=5.0 tests=DATE_IN_PAST_12_24,HTML_40_50,HTML_MESSAGE,MAILTO_TO_SPAM_ADDR autolearn=no version=2.60 X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-PN-SPAMFiltered: yes X-Spam-Rating: 2 Content-transfer-encoding: 8bit
 
----- Original Message -----
From: Dick
Sent: Thursday, January 22, 2004 7:44 PM
Subject: LF: 136kHz project cancelled

 
Hi Dick
Get rid of your troubles immediately by building the G3YXM or G0MRF designed 137 khz transmitters/amplifiers.
I have used a modified YXM design for years and it has proved very reliable. There is no point re-inventing the WHEEL
The components including chips are cheap. I have replaced the output transformer 3C85 core with an old TV line output core and it works just as well, I cannot detect any difference in RF output or heat etc. I have always used a fan blowing across this transformer and the LPF inductors plus another fan blowing across the MOSFET heatsink compartment.
The amplifier runs very COOL, heatsink just warm and the output transformer and LFP cold.
I use an ICOM 706 on 13.7 mhz and divide down to the required 137 khz frequency.
I use 4 mosfets 75N10 type and with a suitable PSU these are capable of nearly 1KW output. It depends what you have available but try 12 - 20 Volts, the current could be up to 50 plus amps !!!!!!!.
Good Luck and be careful AVOID smoke
de Mal/G3KEV