Return-Path: Received: (qmail 11175 invoked from network); 10 Feb 2004 09:36:51 -0000 Received: from unknown (HELO ptb-mxscan01.plus.net) (212.159.14.235) by ptb-mailstore02.plus.net with SMTP; 10 Feb 2004 09:36:51 -0000 Received: (qmail 13937 invoked from network); 10 Feb 2004 09:36:50 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Priority: 3 X-MSMail-Priority: Normal X-Spam-detection-level: 11 Received: from ptb-mxcore01.plus.net (212.159.14.215) by ptb-mxscan01.plus.net with SMTP; 10 Feb 2004 09:36:49 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim 4.30; FreeBSD) id 1AqUK1-0003Ut-NW for dave@picks.force9.co.uk; Tue, 10 Feb 2004 09:36:49 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AqUJ1-0003wu-Fm for rs_out@blacksheep.org; Tue, 10 Feb 2004 09:35:47 +0000 Received: from [192.5.29.49] (helo=relay.dstl.gov.uk) by post.thorcom.com with smtp (Exim 4.14) id 1AqUIz-0003wj-UR for rsgb_lf_group@blacksheep.org; Tue, 10 Feb 2004 09:35:46 +0000 Received: (qmail 5977 invoked from network); 10 Feb 2004 09:35:42 +0000 X-Fake-Domain: unknown Received: from unknown (HELO warlock.dstl.gov.uk) (192.5.29.10) by relay.dera.gov.uk with SMTP; 10 Feb 2004 09:35:42 +0000 Message-ID: <7D653C9C42F5D411A27C00508BF8803D01A9F40F@mail.dstl.gov.uk> From: "Talbot Andrew" To: rsgb_lf_group@blacksheep.org Date: Tue, 10 Feb 2004 09:35:40 -0000 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2657.72) Subject: RE: LF: Timing GPS Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.60 X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-PN-SPAMFiltered: yes X-Spam-Rating: 1 Judging by the lack of replies to this thread - there seems little interest here. A very great pity, as accurate GPS locked timing is the next great improvement we could make to LF signalling. I have been evaluating a lot of low cost GPS receiver modules recently. The Navman Jupiter module (available from www.tdc.co.uk for around £86) has a very useful 10kHz output from it as well as the one pulse per second. Using Argo to look at this 10kHz signal multiplied up to 10MHz, I couldn't detect any 1Hz sidebands on it. If this is really the case, the 10kHz will considerably simplify locked frequency sources as PLL bandwidths can presumably be widened and lock up times reduced. I'm a bit sceptical that the 10kHz signal can have a significantly better short term stability than the 1 PPS, but it is worth testing further. Andy G4JNT -----Original Message----- From: WarmSpgs@aol.com [mailto:WarmSpgs@aol.com] Sent: 2004 February 08 21:23 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Timing GPS In the month since the thread started, interest has picked up on this side of the pond in using GPS to synchronize timing of digital modes. No longer having to hunt and test for bit and frame timing, the efficiency of "classic" LF digital modes like BPSK improves immensely--even without referencing the carrier to GPS. "This e-mail is intended for the recipient only. If you are not the intended recipient you must not use, disclose, distribute, copy, print, or rely upon this e-mail. If an addressing or transmission error has misdirected this e-mail, please notify the author by replying to this e-mail." "Recipients should note that all e-mail traffic on MOD systems is subject to monitoring and auditing."