Return-Path: Received: (qmail 7173 invoked from network); 4 Jan 2005 20:56:26 -0000 Received: from unknown (HELO ptb-spamcore02.plus.net) (192.168.71.3) by ptb-mailstore01.plus.net with SMTP; 4 Jan 2005 20:56:26 -0000 Received: from mailnull by ptb-spamcore02.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1Clvhm-000FTQ-V5 for dave@picks.force9.co.uk; Tue, 04 Jan 2005 20:55:03 +0000 Received: from [192.168.67.3] (helo=ptb-mxcore03.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.32; FreeBSD) id 1Clvhm-000FT9-De for dave@picks.force9.co.uk; Tue, 04 Jan 2005 20:55:02 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore03.plus.net with esmtp (Exim) id 1Clvj6-000Cyu-LU for dave@picks.force9.co.uk; Tue, 04 Jan 2005 20:56:24 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Clvih-0000gG-Nn for rs_out_1@blacksheep.org; Tue, 04 Jan 2005 20:55:59 +0000 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Clvih-0000g7-9r for rsgb_lf_group@blacksheep.org; Tue, 04 Jan 2005 20:55:59 +0000 Received: from sccrmhc11.comcast.net ([204.127.202.55]) by relay.thorcom.net with esmtp (Exim 4.41) id 1Clvic-00065p-Es for rsgb_lf_group@blacksheep.org; Tue, 04 Jan 2005 20:55:59 +0000 Received: from Charlie_Drake (pcp08521272pcs.lebnon01.pa.comcast.net[69.139.251.25]) by comcast.net (sccrmhc11) with SMTP id <2005010420554201100g79mqe>; Tue, 4 Jan 2005 20:55:47 +0000 From: Steve Dove To: rsgb_lf_group@blacksheep.org Date: Tue, 04 Jan 2005 20:54:01 -0000 X-Priority: 3 (Normal) Organization: d s p In-Reply-To: Message-Id: MIME-Version: 1.0 X-Mailer: Opera 6.04 build 1135 X-SPF-Result: relay.thorcom.net: 204.127.202.55 is neither permitted nor denied by domain of hifidelity.com X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=failed,none Subject: Re: RE: LF: TA 04Jan Content-Type: text/plain; charset=US-ASCII; format=flowed X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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-Spam-Filtered: by PlusNet SpamCORE (v3.00) Content-transfer-encoding: 8bit Hi Joe, Laurence, I have an FT857D (a wattier 817) in my car, and its deafness is of heroic proportions. If I were asked to come up with something that worked so well at HF but so dismally at LF, it'd be a struggle. It can't hear an NDB unless it's within about a hundred yards of it; absolutely amazing. So similarly, I use an Altoids tin containing a 500kHz low-pass filter and two series'd preamps to render it useful. Each preamp's configuration is based on: http://w7iuv.com/preamp.jpg only using FT50-J cores instead. It is broadly similar to a preamp by our very own Mr. Rusgrove, I believe the details of which are on John, W1TAG's site. Cheers, Steve 01/04/05 20:20:04, Joe Craig wrote: >I use a "Burhans" preamp with my FT-817. The measured gain >was 30-35 dB. Like the G0MRF version Laurence is using, >it uses a BJT and FET with a somewhat enigmatic biasing >arrangement for the BJT. > >The 817 is very deaf without a preamp. > >73 >Joe VO1NA > > > >