Return-Path: <owner-rsgb_lf_group@blacksheep.org> Received: (qmail 3498 invoked from network); 5 Feb 2004 21:52:16 -0000 Received: from unknown (HELO ptb-mxscan02.plus.net) (212.159.14.236) by ptb-mailstore01.plus.net with SMTP; 5 Feb 2004 21:52:16 -0000 Received: (qmail 63826 invoked from network); 5 Feb 2004 21:52:34 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Priority: 3 X-MSMail-Priority: Normal X-Spam-detection-level: 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from ptb-mxcore02.plus.net (212.159.14.216) by ptb-mxscan02.plus.net with SMTP; 5 Feb 2004 21:52:33 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore02.plus.net with esmtp (Exim) id 1AorQH-000GTW-7B for dave@picks.force9.co.uk; Thu, 05 Feb 2004 21:52:33 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AorPh-0002U0-Oy for rs_out@blacksheep.org; Thu, 05 Feb 2004 21:51:57 +0000 Received: from [64.12.136.7] (helo=imo-m04.mx.aol.com) by post.thorcom.com with esmtp (Exim 4.14) id 1AorPh-0002Tr-1U for rsgb_lf_group@blacksheep.org; Thu, 05 Feb 2004 21:51:57 +0000 X-Fake-Domain: G0MRF@aol.com Received: from G0MRF@aol.com by imo-m04.mx.aol.com (mail_out_v36_r4.12.) id l.8d.2a72ee9 (3699) for <rsgb_lf_group@blacksheep.org>; Thu, 5 Feb 2004 16:51:17 -0500 (EST) From: G0MRF@aol.com Message-ID: <8d.2a72ee9.2d5414d5@aol.com> Date: Thu, 5 Feb 2004 16:51:17 EST To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 X-Mailer: 8.0 for Windows sub 670 Subject: Re: LF: RE: G0MRF 300w Tx & DDS VFO 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-Status: No, hits=0.7 required=5.0 tests=HTML_MESSAGE,HTML_TAG_BALANCE_HTML,NO_REAL_NAME autolearn=no version=2.60 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@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-PN-SPAMFiltered: yes X-Spam-Rating: 1 Content-transfer-encoding: 8bit <HTML><FONT FACE=arial,helvetica><HTML><FONT SIZE=2 PTSIZE=10 FAMILY="SANSSERIF" FACE="Arial" LANG="0">In a message dated 2/5/04 9:45:06 PM GMT Standard Time, g4wgt@talkgas.net writes:<BR> <BR> <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Thanks for the very useful data Jim, I did in fact get a reply from the<BR> organiser of the kit/project &he has stated that several builders have<BR> experienced the same low output &have diagnosed a faulty modamp, I have<BR> doubly checked for the sort of error you suggest &that seems ok, also there<BR> is some gain thro' the ERA-1SM. Now that I have some figures to refer to I<BR> can have another look at the signal path etc. From memory I don't believe<BR> that I am getting anywere near 250mV p-p from the DDS IC before any<BR> amplification takes place.<BR> <BR> </BLOCKQUOTE><BR> <BR> There have been some problems with the ERA series of Mod-amps. Even the older MAR series has encountered problems after a change from Silicon to a Silicon/Germanium production process.<BR> <BR> Some of the Modamps have a white dot marking the input, others have a dot on the output lead. However, all have the input lead clipped at a 45 degree angle.<BR> <BR> Correct operation can usually assessed by the voltage on the output lead.<BR> <BR> Any short, even for a fraction of a second, on the input lead removes the bias from the FETs and destroys the device.<BR> <BR> 73<BR> <BR> David </FONT></HTML>