Return-Path: Received: (qmail 12910 invoked from network); 12 Jul 2002 07:59:35 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 12 Jul 2002 07:59:35 -0000 Received: (qmail 29562 invoked from network); 12 Jul 2002 07:58:43 -0000 X-MSMail-Priority: High Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 12 Jul 2002 07:58:43 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 17SvGt-0007X2-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 12 Jul 2002 08:55:23 +0100 Received: from smtp-1.visp.telinco.net ([212.1.130.1]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 17SvGs-0007Wx-00 for rsgb_lf_group@blacksheep.org; Fri, 12 Jul 2002 08:55:23 +0100 Received: from [212.1.154.245] (helo=standalone) by smtp-1.visp.telinco.net with smtp (Exim 3.32 #1) id 17SvER-0001po-00 for rsgb_lf_group@blacksheep.org; Fri, 12 Jul 2002 08:52:52 +0100 Received: by localhost with Microsoft MAPI; Fri, 12 Jul 2002 08:54:31 +0100 Message-ID: <01C22981.BCD4AE10.g4jnt@thersgb.net> From: "Andy talbot" To: rsgb_lf_group@blacksheep.org Subject: RE: LF: WWVB Date: Fri, 12 Jul 2002 08:54:25 +0100 Importance: high X-Priority: 1 X-Mailer: Microsoft Internet E-mail/MAPI - 8.0.0.4211 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: If WWVB is 2800km from us, then the signal takes 9ms to get here. Assuming the shape of the pulses is the same as for MSF ie a carrier break for 100 - 300ms timed to start exactly at the UTC second , then there will be a period from UTC +0 to UTC + 9ms when it ought to be possible to receive WWVB during the MSF off period. By gating out the received signal and coherently averaging, we can now have .009 / 1s worth of WWVB data, ie a signal strength 20dB below what would otherwise be possible. With GPS based timing, deriving this gating period is trivial, but even witout GPS, MSF can probably be used itself to generate the timing I'm not proposing to do this, just throwing an idea into the ring ;-) but know how you like to take on challenges Jim. Andy G4JNT In the UK we have MSF, also on 60kHz, which is a big signal here (several millivolts/metre) - so I am unlikely to ever hear WWVB at my QTH! RX antennas are a variety of tuned wires and loops, usually whatever is giving the lowest level of mains-bourne noise at that particular frequency and time.