Return-Path: Received: (qmail 5390 invoked from network); 29 Sep 1999 21:13:27 +0100 Received: from unknown (HELO magnet.force9.net) (195.166.128.26) by guiness.force9.net with SMTP; 29 Sep 1999 21:13:27 +0100 Received: (qmail 27070 invoked from network); 29 Sep 1999 20:18:53 -0000 Content-Transfer-Encoding: 8bit Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnet.plus.net.uk with SMTP; 29 Sep 1999 20:18:53 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 11WPwL-0000hF-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 29 Sep 1999 21:03:01 +0100 X-Priority: 3 X-MSMail-Priority: Normal Received: from premium.inrete.it ([194.116.9.4] helo=mailer.inrete.it ident=root) by post.thorcom.com with esmtp (Exim 3.02 #1) id 11WPwK-0000hA-00 for rsgb_lf_group@blacksheep.org; Wed, 29 Sep 1999 21:03:00 +0100 Received: from cel266 (pool17-011.dialup.alpcom.it [194.116.17.11]) by mailer.inrete.it (8.8.8/8.8.8) with SMTP id WAA00341 for ; Wed, 29 Sep 1999 22:02:54 +0200 Message-ID: <3.0.3.32.19990929220150.00881ca0@mailer.inrete.it> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Sender: spin@mailer.inrete.it X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.3 (32) Date: Wed, 29 Sep 1999 22:01:50 +0100 To: rsgb_lf_group@blacksheep.org From: "M. Bruno" Subject: LF: 136kHz receivers In-reply-to: <3.0.1.16.19990929131638.1e37bd9e@mail.cc.kuleuven.ac.be> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi all, I agree with Toni observing that a 500 Hz filter is too wide for serious weak signal work. I use a Racal 1792, modified with 300 Hz and 100 Hz filters, followed by an audio (analogic) filter. The 100 Hz one, if well designed (no appreciable ringing) helps a lot. I also tried an attenuator in front of the RA1792. In my location I have no need for it; I prefer to reduce the IF gain. The first mixer seems tough enough (103 dB 3' order IMD measured). Vaino, are you sure those RX are not designed for weak signal work? In my opinion it is VERY good. I also tried many others, and I keep the RA1792 as my main RX. 73 - Marco IK1ODO spin@inrete.it Rivalta, ITALY JN35SA (N 45 01' 25.6", E 7 31' 09.4")