Return-Path: Received: (qmail 2052 invoked from network); 18 Jan 2002 11:21:36 -0000 Received: from unknown (HELO warrior.services.quay.plus.net) (212.159.14.227) by excalibur-qfe1-smtp-plusnet.harl.plus.net with SMTP; 18 Jan 2002 11:21:36 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 16485 invoked from network); 18 Jan 2002 11:21:34 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior.services.quay.plus.net with SMTP; 18 Jan 2002 11:21:34 -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 16RX2z-00041m-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 18 Jan 2002 11:19:01 +0000 Received: from bob.dera.gov.uk ([192.5.29.90]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16RX2y-00041h-00 for rsgb_lf_group@blacksheep.org; Fri, 18 Jan 2002 11:19:00 +0000 Received: by bob.dera.gov.uk; (8.8.8/1.3/10May95) id LAA30727; Fri, 18 Jan 2002 11:28:00 GMT Received: (qmail 16059 invoked from network); 18 Jan 2002 12:07:02 -0000 Received: from gauntlet.mail.dstl.gov.uk (192.168.9.10) by baton.dstl.gov.uk with SMTP; 18 Jan 2002 12:07:02 -0000 Received: by gauntlet.mail.dstl.gov.uk; id LAA04148; Fri, 18 Jan 2002 11:36:21 GMT Received: from unknown(172.17.128.171) by gauntlet.mail.dstl.gov.uk via smap (3.2) id xma004134; Fri, 18 Jan 02 11:35:53 GMT Received: from FRN-MAIL-R3.dstl.gov.uk (unverified) by mailguard.dstl.gov.uk (Content Technologies SMTPRS 4.1.5) with ESMTP id for ; Fri, 18 Jan 2002 11:24:20 +0000 Received: by frn-mail-r3.dstl.gov.uk with Internet Mail Service (5.5.2650.21) id ; Fri, 18 Jan 2002 11:17:44 -0000 Message-ID: <7D653C9C42F5D411A27C00508BF8803DCB995A@pdw-mail-r1.dstl.gov.uk> From: "Talbot Andrew" To: rsgb_lf_group@blacksheep.org Subject: RE: LF: G0MRF/SM6LKM DDS VFO and Jason Date: Fri, 18 Jan 2002 11:17:35 -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: >OK. It looks like we already have a standard. Andy, can you describe your protocol? I'll send it out under separate cover. >If we all clock our DDS chips with 5 or 10MHz from frequency standards, we >will have common "channels" although the numbers will not be nice (a lot of This is too prescriptive. For instance, I am looking at a simple GPS locking scheme that will allow any frequency that is a multiple of 1Hz to be locked giving very good long term stability, but poor short term over a few seconds - suitable for long duration signalling purposes. Using a 4.194304MHz is perfect for DDS synths as 'nice' frequencies occur automatically. The step is 1/1024Hz so 1Hz steps and its subdivisions are exact >It is probably a good idea to make soft phase >transitions considering the huge reactive power that is circulating in the >antenna circuits at the QRO stations. Swiching phase 180 degrees >instantaneously in such a setup would be like throwing in the reverse gear >when driving forward at 100 MPH... A Tx with a guard circuit such as the Decca one can survive such abuse - the only real problems is an ethical one of switching sidebands - but a spike of a few 100s of microseconds, a function of the antenna bandwidth, every few 10s of seconds isn't going to annoy too many people. BTW, What's MPH in Sweden - or any other country outside the US/UK for that matter ;-) 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.