Return-Path: Received: from mtain-dh11.r1000.mx.aol.com (mtain-dh11.r1000.mx.aol.com [172.29.65.31]) by air-da08.mail.aol.com (v128.1) with ESMTP id MAILINDA082-86184bafa2993e0; Sun, 28 Mar 2010 14:40:25 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dh11.r1000.mx.aol.com (Internet Inbound) with ESMTP id 7308538000181; Sun, 28 Mar 2010 14:40:23 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NvxNz-0004WI-NC for rs_out_1@blacksheep.org; Sun, 28 Mar 2010 19:38:59 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NvxNz-0004W9-6u for rsgb_lf_group@blacksheep.org; Sun, 28 Mar 2010 19:38:59 +0100 Received: from smtp815.mail.ukl.yahoo.com ([217.12.12.244]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1NvxNx-000116-Dy for rsgb_lf_group@blacksheep.org; Sun, 28 Mar 2010 19:38:59 +0100 Received: (qmail 70306 invoked from network); 28 Mar 2010 18:38:51 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=IyhuGgNkMW+WJ91DHuCMJwwjrkk12H8015G70GyK3MBaXm2PQ7rU0mDIr5FboJ9Z3pYgKAKfud4xSZEpUL6SmR5X5mr53vMmqTOfriFV4JwDmI6KSmaubfwMIo7iK1WRKW3F4xasXp4+aZH6adTNLs2d6C6+rQ66tfvulMPjzBI= ; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btopenworld.com; s=s1024; t=1269801531; bh=EFTTBpYpPDa+6E5vzzHoZQtYB64gCTghD6uJ67bxytc=; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=l4RH4F7Fv0wMojysLgMhficOZrTmMMrTgRPUYhYD4Jme72lNCbikAv2xPycG2wVG0GP8PtknWWBWWPTlCZU8oFVBLYMqGGbe7EMSajZdgfxiEn4+C8XB2TNsrB6gmalH1HsHLnjnDC9BGDbaxQUVK07IyucPxrM051xz5zeGaD4= Received: from JimPC (james.moritz@86.180.204.156 with login) by smtp815.mail.ukl.yahoo.com with SMTP; 28 Mar 2010 18:38:51 +0000 GMT X-Yahoo-SMTP: Cxhli3eswBD1ozmtAojhjrja86kWx0Qm9tycD5QR1DKWrOLgjJcXkw-- X-YMail-OSG: jkm7vEwVM1mH0xBbgudJTJlVbFDZFw8LaLRR0rK2xW_M8.3slCMgNw0oNO3.6JvG74AlOwFZVNNfEF5v8THWZKtJQgRiTiYXY6X1BEOfLTWfHxL4xbcPWRL6vPe6lBPZy3rOrujmmt.SJ4DmtyvkrDrVUZwXDwKE1F60FCLpfxeO.tt8ShFuwZm1Io1JAhym1bhswdGwBCCdrHvzRauUVYs7_5O9LmXSjpw3tzRFKxQrC_.zpwSvI0PwUgDHAEbfnilQn.odb0vcz8USvRpnXLMu5qtIBgTqBw-- X-Yahoo-Newman-Property: ymail-3 Message-ID: From: "James Moritz" To: References: <20100324105125.4F2CC31E703@smtps01.kuleuven.be> <9afca2641003281040g1748a9c3lc4a20004327085ae@mail.gmail.com> In-Reply-To: <9afca2641003281040g1748a9c3lc4a20004327085ae@mail.gmail.com> Date: Sun, 28 Mar 2010 19:38:51 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18005 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18005 DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,UNPARSEABLE_RELAY=0.001 Subject: LF: Re: DK7FC's 3rd VLF transmission Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.1 required=5.0 tests=MISSING_OUTLOOK_NAME 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-global-disposition: G X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d274.2 ; domain : btopenworld.com DKIM : fail x-aol-sid: 3039ac1d411f4bafa2973a3a X-AOL-IP: 193.82.116.20 Dear Roger, LF Group, The ZTX690B is in current production, and is available from suppliers like RS components, Farnell, Rapid in the UK, or Digi-Key and so on. In this particular application, with this source impedance and bias current, etc., I found the BC337 and 2N2222A performed almost as well, as probably will many other "switching" and "driver" transistors rated at several hundred mA Ic and with high beta. At lower source impedance levels in other circuits I have designed, such as the bandpass loop preamp, the ZTX690B performs significantly better as a low noise preamp. Cheers, Jim Moritz 73 de M0BMU ----- Original Message ----- From: "Roger Lapthorn" To: Sent: Sunday, March 28, 2010 6:40 PM Subject: Re: Re: LF: Re: DK7FC's 3rd VLF transmission *Jim,* Thanks for the updated preamp schematic. What would you recommend as a suitable alternative to the ZTX690B device in your 8.97kHz preamp as I don't think these are available nowadays?