Return-Path: Received: (qmail 5063 invoked from network); 19 Feb 2002 10:04:18 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by excalibur-qfe1-smtp-plusnet.harl.plus.net with SMTP; 19 Feb 2002 10:04:18 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 4863 invoked from network); 19 Feb 2002 10:04:18 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 19 Feb 2002 10:04:18 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16d8Ws-00080U-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 19 Feb 2002 11:33:50 +0000 Received: from bob.dera.gov.uk ([192.5.29.90]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16d8Wr-00080P-00 for rsgb_lf_group@blacksheep.org; Tue, 19 Feb 2002 11:33:49 +0000 Received: by bob.dera.gov.uk; (8.8.8/1.3/10May95) id KAA31037; Tue, 19 Feb 2002 10:06:22 GMT Received: (qmail 23854 invoked from network); 19 Feb 2002 10:43:18 -0000 Received: from gauntlet.mail.dstl.gov.uk (192.168.9.10) by baton.dstl.gov.uk with SMTP; 19 Feb 2002 10:43:18 -0000 Received: by gauntlet.mail.dstl.gov.uk; id KAA00244; Tue, 19 Feb 2002 10:10:00 GMT Received: from unknown(172.17.128.171) by gauntlet.mail.dstl.gov.uk via smap (3.2) id xma000215; Tue, 19 Feb 02 10:09:48 GMT Received: from FRN-MAIL-R3 (unverified) by mailguard.dstl.gov.uk (Content Technologies SMTPRS 4.1.5) with ESMTP id for ; Tue, 19 Feb 2002 10:03:25 +0000 Received: by FRN-MAIL-R3 with Internet Mail Service (5.5.2650.21) id ; Tue, 19 Feb 2002 09:55:30 -0000 Message-ID: <7D653C9C42F5D411A27C00508BF8803DCB99CC@pdw-mail-r1.dstl.gov.uk> From: "Talbot Andrew" To: rsgb_lf_group@blacksheep.org Subject: LF: PSK08 and Jims Vectorscope Date: Tue, 19 Feb 2002 09:55:23 -0000 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset=iso-8859-1; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Firstly, Jim, can you send me a copy of your vectorscope circuit please - it may be a case of "Coals to Newcastle" but I'm intrigued ! Now, how about the next version, a direct conversion receiver generating quadrature signals at 137kHz then having masses of low frequency gain before the X/Y plot ? .......... Secondly, referring to Wolf's and others earlier postings. I believe linear modes such as PSK08 are probably of little value on this band for weak signal working. PSK31 (and hence ..08, ..01 etc) have been heavily optimised for bandwidth reduction at the expense of signalling efficiency, and result in a minor degradation compared with harder switched PSK modes. Where bit symbols approach one second, we need to decide if the key clicks really are a problem - at 1 symbol per second I doubt very much anyone is going to notice them. For PSK31 itself, which is a lot faster and slightly better than 18WPM CW in signalling performance, this argument probably is not true though. As the spectrum from overdriven transmitters often shows ! The complexities and inefficieny of using a linear Tx, just to keep the bandwidth down for PSK08 and ..01 when hardly anyone one will notice is mainly one of conscience I guess ! Andy G4JNT -- The Information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful.