Return-Path: Received: from rly-md08.mx.aol.com (rly-md08.mail.aol.com [172.20.29.146]) by air-md09.mail.aol.com (v125.7) with ESMTP id MAILINMD091-91a4aa1303f377; Fri, 04 Sep 2009 11:20:44 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-md08.mx.aol.com (v125.7) with ESMTP id MAILRELAYINMD082-91a4aa1303f377; Fri, 04 Sep 2009 11:20:32 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1MjaZL-0002f5-4p for rs_out_1@blacksheep.org; Fri, 04 Sep 2009 16:19:19 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1MjaZK-0002ew-5g for rsgb_lf_group@blacksheep.org; Fri, 04 Sep 2009 16:19:18 +0100 Received: from idcmail-mo1so.shaw.ca ([24.71.223.10]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1MjaYO-000551-Jy for rsgb_lf_group@blacksheep.org; Fri, 04 Sep 2009 16:18:21 +0100 Received: from pd2ml1so-ssvc.prod.shaw.ca ([10.0.141.139]) by pd3mo1so-svcs.prod.shaw.ca with ESMTP; 04 Sep 2009 09:19:01 -0600 X-Cloudmark-SP-Filtered: true X-Cloudmark-SP-Result: v=1.0 c=1 a=9hEPxwfszBkA:10 a=hpRB0Fap9I/LtfPfVks2Bw==:17 a=F3M5lZpKAAAA:8 a=s5CBfqyokMi0TwTWq-wA:9 a=juD93u2M4GWDmm1hsH_XbqEn9REA:4 a=wk6s2zzMB60A:10 a=sLtajfu03cwsXFjy:21 a=dbpY1j5KH77iZXSj:21 Received: from unknown (HELO NIS942960248) ([68.147.17.149]) by pd2ml1so-dmz.prod.shaw.ca with SMTP; 04 Sep 2009 09:19:01 -0600 Message-ID: From: "Jordan" To: References: <9afca2640908261406r3ced27fr31bbca942848a291@mail.gmail.com> <005701ca2707$438a4570$0301a8c0@mal769a60aa920> <9afca2640908270502q3136dd1cjf52d2666eedeed94@mail.gmail.com> <009c01ca2731$2d5e0e60$0301a8c0@mal769a60aa920> <9afca2640908271133v7eea7f18r7855a822514399a4@mail.gmail.com> <847F3A04E31C413A81AD022BDC11AD46@JimPC> <5CA746FC83614040A4C4D8B6F9F2519E@NIS942960248> <200909041044070836.0E08CA55@smtp2.numeo.fr> Date: Fri, 4 Sep 2009 09:19:01 -0600 Organization: VE6ZT MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Karma: unknown: X-Spam-Score: 3.4 (+++) X-Spam-Report: autolearn=disabled,FORGED_MUA_OUTLOOK=3.36 Subject: Re: LF: Low frequency preselectors? Content-Type: text/plain; format=flowed; charset="iso-8859-15"; 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=2.5 required=5.0 tests=FORGED_MUA_OUTLOOK, FROM_ENDS_IN_NUMS 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 Thanks Roelof..! It looks like a fairly narrow band preamp with good Q...I guess it depends on the Q of the inductors...I'll put the design to good use..! 73...Jordan.... ----- Original Message ----- From: "Roelof Bakker" To: Sent: Friday, September 04, 2009 3:54 AM Subject: Re: LF: Low frequency preselectors? > Hello Jordan, > > Sorry for the delay, I just forgot to answer your question. > > In the attachment you will find the circuit diagram of a tuneable > pre-amplifier. > I have build several of these and the frequency response is quite narrow. > The circuit has ample gain and using the rf-gain control, the tuned > circuit is "damped", which broadens the response. The gain is realised by > the impedance transformation of the tuned circuit, which results in > considerable voltage gain. The amplifier is a voltage follower with an > output impedance of 50 ohm. > > Best regards, > Roelof Bakker, pa0rdt