Return-Path: Received: from rly-da08.mx.aol.com (rly-da08.mail.aol.com [172.19.129.82]) by air-da03.mail.aol.com (v123.4) with ESMTP id MAILINDA034-a8349ca4780296; Wed, 25 Mar 2009 11:02:43 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-da08.mx.aol.com (v123.4) with ESMTP id MAILRELAYINDA083-a8349ca4780296; Wed, 25 Mar 2009 11:02:25 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LmUcH-0000Em-4w for rs_out_1@blacksheep.org; Wed, 25 Mar 2009 15:02:05 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LmUcG-0000Ed-OZ for rsgb_lf_group@blacksheep.org; Wed, 25 Mar 2009 15:02:04 +0000 Received: from relay.pcl-ipout01.plus.net ([212.159.7.99]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1LmUcF-0007Ot-Hm for rsgb_lf_group@blacksheep.org; Wed, 25 Mar 2009 15:02:04 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AjQOAAvkyUnUnw6S/2dsb2JhbACBSoheg2vEM4N1Bg Received: from ptb-relay02.plus.net ([212.159.14.146]) by relay.pcl-ipout01.plus.net with ESMTP; 25 Mar 2009 15:00:58 +0000 Received: from [212.159.90.113] (helo=Hugh) by ptb-relay02.plus.net with smtp (Exim) id 1LmUbB-0007uu-Hd for rsgb_lf_group@blacksheep.org; Wed, 25 Mar 2009 15:00:57 +0000 Message-ID: <86B4F549F8F247DDA470143B3BE77364@Hugh> From: "Hugh_m0wye" To: References: Date: Wed, 25 Mar 2009 15:00:50 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Plusnet-Relay: 23843678ecf466f75e4f9af95ab5e3cd X-Spam-Score: 3.4 (+++) X-Spam-Report: autolearn=disabled,FORGED_MUA_OUTLOOK=3.36 Subject: LF: Re: TDA2003, TDA2030 for PA? Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.6 required=5.0 tests=FORGED_MUA_OUTLOOK 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 X-AOL-IP: 193.82.116.20 I successfully made a TDA2030 amplifier which i used for all my intial experimenting on 137kHz Photo http://www.m0wye.radiouk.com/lfamp.jpg The data sheet for this IC claims a bandwidth of 140kHz so it won't work on 500kHz. I think I got about 6Watts out. Not all the audio ICs have as much bandwidth as this. You need a matching circuit on the output to convert the low impedance of the amp to 50 ohms - or whatever your antenna system uses. 73 Hugh M0WYE ----- Original Message ----- From: "Petr Malư" To: Sent: Wednesday, March 25, 2009 1:38 PM Subject: LF: TDA2003, TDA2030 for PA? Hi all, My intention is to build a small transmitter up to some 10W for 136 and 505 kHz, this time not the D class, but B or AB class. I think of employing AF amplifiers such as TDA2003, TDA2030, or similar. Of course, mainly 505 kHz is rather out of range so that nothing is guaranteed. This is why I ask before experimenting. Did anybody try to use these for 136/505 kHz? Tks, 73, Petr, OK!FIG http://ok1fig.nagano.cz