Return-Path: Received: (qmail 25482 invoked from network); 1 Dec 2002 00:13:20 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 1 Dec 2002 00:13:20 -0000 Received: (qmail 18410 invoked from network); 1 Dec 2002 00:13:08 -0000 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 1 Dec 2002 00:13:08 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18IHiB-00053c-00 for rsgb_lf_group-outgoing@blacksheep.org; Sun, 01 Dec 2002 00:11:51 +0000 Received: from [165.254.158.18] (helo=mail.mcf.com) by post.thorcom.com with esmtp (Exim 4.10) id 18IHiB-00053T-00 for rsgb_lf_group@blacksheep.org; Sun, 01 Dec 2002 00:11:51 +0000 Received: from parissn2 (213.41.137.138) by mail.mcf.com with ESMTP (Eudora Internet Mail Server 3.2b2) for ; Sat, 30 Nov 2002 19:11:52 -0500 Message-ID: <007101c298ce$4ee04240$0700000a@parissn2> From: "Stewart Nelson" To: rsgb_lf_group@blacksheep.org References: <002001c298a4$647bf920$9eb901d5@main> Date: Sun, 1 Dec 2002 01:12:15 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: LF: Re: Frequency Standards..... Content-Type: text/plain; charset=Windows-1252; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=-0.6 required=5.0tests=QUOTED_EMAIL_TEXT,REFERENCES,SPAM_PHRASE_01_02, USER_AGENT_OEversion=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Hi Alan and all, Thanks for the link. Another fascinating read, with some awesome charts, is David Allan's "The Science of Timekeeping", which can be downloaded (PDF, 1.13 MB) at http://www.allanstime.com/Publications/DWA/Science_Timekeeping/ 73, Stewart KK7KA > Hi all, ever wondered what a Cesium Clock was...... or how a Rubidium > standard worked.....why do crystals "age"..... ?? > It's all explained now....I found an old copy of an NBS Tutorial (dated > 1977) which covers all these and many more interesting facets of Time and > Frequency standards. I have scanned it and made it available as a .PDF file > in two parts, which can be downloaded from the index page of my web site. It > even covers the 2003 "must have" the Hydrogen Maser....anyone for parts in > 10^13 ?? > > Cheers de Alan G3NYK > alan.melia@btinternet.com > http://www.alan.melia.btinternet.co.uk