Return-Path: X-Spam-DCC: paranoid 1233; Body=3 Fuz1=3 Fuz2=3 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.5 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,RATWARE_GECKO_BUILD autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id tANJqj2v018078 for ; Mon, 23 Nov 2015 20:52:45 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1a0x6w-000360-St for rs_out_1@blacksheep.org; Mon, 23 Nov 2015 19:49:14 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1a0x6w-00035r-IF for rsgb_lf_group@blacksheep.org; Mon, 23 Nov 2015 19:49:14 +0000 Received: from parrot.netcom.co.uk ([217.72.171.49]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1a0x5t-0006Ym-Ns for rsgb_lf_group@blacksheep.org; Mon, 23 Nov 2015 19:49:13 +0000 Received: from sb.abelian.org (i-194-106-52-83.freedom2surf.net [194.106.52.83]) by parrot.netcom.co.uk (Postfix) with ESMTP id 461463273F4 for ; Mon, 23 Nov 2015 19:39:08 +0000 (GMT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by sb.abelian.org (Postfix) with ESMTP id B15D828A0031 for ; Mon, 23 Nov 2015 19:47:53 +0000 (UTC) Message-ID: <56536D69.1090800@abelian.org> Date: Mon, 23 Nov 2015 19:47:53 +0000 From: Paul Nicholson User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <56522D9D.7090800@abelian.org> <8D2F388A81E77FB-14CC-CB81B@webmail-vd017.sysops.aol.com> In-Reply-To: <8D2F388A81E77FB-14CC-CB81B@webmail-vd017.sysops.aol.com> X-Scan-Signature: 2e2f7cbbe9f38dd7bf3fac4fc012e6fc Subject: Re: LF: EbNaut LF test from iz7slz Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 5278 Markus wrote: > a 0.5 mHz (not Hz) hourly drift won't affect decoding much. > The difficulty is only that the actual center frequency is > not easily predictable, You're right. It's impractical to search for. The only way is to prefix the message with a spell of carrier long enough to measure F. But strictly speaking that carrier should be included in the overall Eb/N0 budget - it will raise the average Eb and knock about 3dB off the performance. Here I've been testing a Trimble 57963 GPS with PPS and 10MHz DOCXO and it works quite well. Plenty available on ebay. Not quite plug and play because it uses an undocumented RS232 protocol which I've pretty much figured out now. Will have to modify gpsd so that it can work with it. It could become the timer/oscillator for a proper LF receiver. Three MC1496 are staring at me from the junk box. -- Paul Nicholson --