========================================================================
= Information on NTP Time Servers and Radio Timecode Receivers         =
= This update 3 April 1993, last update 1 March 1993                   =
========================================================================

Note: * indicates change since the previous version of this file.

General Information

This file is provided for information purposes only and represents the
best information available at the date posted above. It does not
represent a commitment to provide connectivity or time service on the
part of the operators involved. Further information of a technical
nature can be obtained from the ntp@ni.umd.edu list. To subscribe to
this list, contact ntp-request@ni.umd.edu (Louie Mamakos).
Alternatively, if possible, please subscribe to the newsgroup
comp.protocols.time.ntp which is gatewayed to the mailing list. Send
corrections or additions to mills@udel.edu (Dave Mills).

Time Servers

As the load on the hosts supporting NTP primary time (stratum 1) service
is heavy and always increasing, clients should avoid using the primary
servers whenever possible. In most cases the accuracy of the secondary
servers is only slightly degraded relative to the primary servers and,
as a group, the secondary servers may be just as reliable. As a general
rule, a client should use a primary server only under the following
conditions:

1.   The server provides synchronization to a sizable population of
     clients on the order of 100 or more.

2.   The server operates with at least two and preferably three other
     servers in a common synchronization subnet designed to provide
     reliable service even if some servers or the lines connecting them
     fail.

3.   The administration(s) that operates the subnet coordinates other
     clients within the region in order to reduce the resources required
     outside that region. Note that at least some interregional
     resources are required in order to ensure reliable service.

In order to ensure reliability, clients should spread their use over
many different servers. As a general rule, no more than two clients per
network should use the same server on another network; however, in order
to simplify management of host configuration tables, many hosts on the
same network may use the same (redundant) servers on the same network.
Further information on client configuration can be found in the
information files in the pub/ntp/doc directory and in the NTP
distributions ntp.3.4 and xntp3 in the pub/ntp directory, both on
louie.udel.edu.

Unix users are strongly encouraged to adopt the latest NTP Version 3
software in the compressed tar distribution of xntp3.tar.Z in the
pub/ntp directory on louie.udel.edu. Besides providing more accurate,
reliable service, this version automatically increases the polling
intervals for all peer associations, but without sacrificing
performance. This can significantly reduce network loads, as well as the
loads on the busy primary servers, some of which have over 250 clients.

Following is a list of NTP primary and secondary time servers known to
be connected to the Internet and may be available for external access.
Each entry gives the host name, Internet address, approximate location
and geographic coordinates, if available, synchronization source
(stratum, type of radio or satellite receiver and host type), suggested
service area, access policy (as notified) and contact name and e-mail
address. Those servers known to be running NTP Version 3 are indicated
as well. It is always wise to consult the DNS to verify host addresses,
which are changed from time to time. When more than one address is
given, preference should given to each in order. All servers are
equipped with uncompensated crystal-stabilized timebases, unless
indicated otherwise.

The contact person should always be notified upon establishment of
regular operations with servers listed as open access. Please respect
the access policy as stated by the contact person. Servers listed as
closed access should NOT be used without prior permission, since this
may disrupt ongoing research in which these servers are involved.

Primary Servers
---------------

apple.com (130.43.2.2)
Location: Apple Computer, Cupertino, CA
Synchronization: NTP primary (WWV clock), VAX/Unix
Service area: NSFNET, BARR region, CSNET
Access policy: open access
Contact: Erik Fair (timekeeper@apple.com)

bitsy.mit.edu (18.72.0.3)
Location: MIT Information Systems, Cambridge, MA
Geographic Coordinates: 42:21:36N, 71:05:24W
Synchronization: NTP primary (WWV clock), VAX/Unix
Service area: NSFNET, NEARnet area
Access policy: open access
Contact: Jeff Schiller (jis@mit.edu)

chantry.hawaii.net (128.171.1.1, 132.160.1.4)
Location: University of Hawaii, Honolulu, HI
Synchronization: NTP primary (WWV/H clock), Sun/Unix
Service area: PACCOM region
Contact: Kevin Mayeshiro (kevin@hawaii.edu)

churchy.udel.edu (128.4.1.5)
Location: University of Delaware, Newark, DE
Geographic Coordinates: 39:40:48.184N, 75:45:3.067W (GPS WGS84)
Synchronization: NTP primary (GPS clock) Bancomm bc700LAN
Service area: NSFNET, SURA region
Access policy: closed access, except for stratum-2 servers providing
synchronization to local networks of ten or more hosts
Contact: Dave Mills (mills@udel.edu)
Note: This server temporarily out of service until further notice.

* clepsydra.dec.com (16.1.0.22)
Location: DEC Western Research Laboratory, Palo Alto, CA
Synchronization: NTP V3 primary (GOES clock), VAX/Ultrix
Service area: NSFNET, BARR region
Access policy: open access
Contact: Jeff Mogul (mogul@decwrl.dec.com)
Note: The host name is an alias used only for time service.

clock.llnl.gov (128.115.14.97)
Location: Lawrence Livermore National Laboratory, Livermore, CA
Synchronization: NTP V3 primary (WWVB clock), Sun 3/60
Service area: BARRNet, ESNet
Access policy: open access
Contact: Joe Carlson (carlson@lll-winken.llnl.gov)

clock.osf.org (130.105.1.156)
Location: Open Software Foundation, Boston, MA
Synchronization: NTP primary (WWV clock), PMAX/Unix
Service area: NSFNET, NEARnet region
Access policy: open access
Contact: Paul Groff (groff@osf.com)
Note: prior permission to access required

flash.bellcore.com (128.96.32.20) changed to pi.bellcore.com

fordgw.srl.ford.com (128.5.192.1)
Location: Ford Scientific Research Laboratory, Dearborn, MI
Synchronization: NTP V3 primary (GOES clock), Fuzzball
Service area: NSFNET, MERIT region
Access policy: closed access; for use only by prior arrangement
Contact: Fred Ball (fball@smail.srl.ford.com)

fuzz.sdsc.edu (132.249.16.1)
Geographic Coordinates: 32:53:7N, 117:14:20W
Location: SDSC Supercomputer Center, San Diego, CA
Synchronization: NTP V3 primary (WWVB clock), Fuzzball
Service area: NSFNET, SDSC region
Access policy: open access
Contact: Gerard K. Newman (gkn@sds.sdsc.edu)

hp850.mbari.org (134.89.2.200)
Location: Monterey Bay Aquarium Research Institute, Pacific Grove, CA
Synchronization: NTP primary (WWV clock), HP/Unix
Service area: NSFNET, BARR region
Access policy: closed access; for use only by prior arrangement
Contact: Bob Herlien (hebo@hp850.mbari.org)

lerc-dns.lerc.nasa.gov (128.156.1.43)
Location: NASA Lewis Research Center, Cleveland, OH
Synchronization: NTP Primary (WWVB clock), Sun/Unix
Service Area: NSFNET, OARNET
Access Policy: open access
Contact: Joe Rossoll (yyjer@scivax.lerc.nasa.gov)

ncarfuzz.ucar.edu (192.43.244.9)
Location: NCAR Supercomputer Center, Boulder, CO
Synchronization: NTP V3 primary (WWVB clock), Fuzzball
Service area: NSFNET, USAN region
Access policy: open access
Contact: Don Morris (morris@windom.ucar.edu)
Note: This server temporarily out of service until further notice.

ncnoc.concert.net (192.101.21.1)
Location: CONCERT Network NOC, Research Triangle Park, NC
Synchronization: NTP V2 primary (WWVB clock), Sun 4, SunOS 4.1.1
Service area: CONCERT region
Access Policy: CONCERT region, other use by prior arrangement
Contact: Joe Ragland (jrr@concert.net)

norad.arc.nasa.gov (192.52.195.10, 128.102.16.10)
Location: NASA Ames Research Center, Moffett Field, CA
Synchronization: NTP primary (WWV clock), Sun/Unix
Service area: NSFNET, BARR region, NASA NSN, DOE ESNET, DDN
Access policy: open access
Contact: Milo Medin (medin@nsipo.arc.nasa.gov)

ntps1-0.uni-erlangen.de (131.188.1.40)
Location: University Erlangen-Nuernberg, D-W8520 Erlangen, FRG
Synchronization: NTP V3 primary (DCF77 PZF receiver (<50us)), Sun
SS2/Unix SunOS 4.1.3
Service area: Germany/Europe
Access policy: open access, pick one of ntps1-*.uni-erlangen.de
Contact: Frank Kardel, Rainer Pruy (time@informatik.uni-erlangen.de)
ntps1-1.uni-erlangen.de (131.188.1.45)
Location: University Erlangen-Nuernberg, D-W8520 Erlangen, FRG
Synchronization: NTP V3 primary (DCF77 PZF receiver (<50us)), Sun
4/490/SunOS 4.1.3
Service area: Germany/Europe
Access policy: open access, pick one of ntps1-*.uni-erlangen.de
Contact: Frank Kardel, Rainer Pruy (time@informatik.uni-erlangen.de)

otc1.psu.edu (128.118.46.3)
Location: Penn State University, University Park, PA
Synchronization: NTP primary (WWV clock), Sun/Unix
Service area: NSFNET, PREPNET, JvNCnet
Access policy: open access
Contact: John Balogh (jdb@ecl.psu.edu)

pi.bellcore.com (128.96.60.5)
Location: Bell Communications Research, Morristown NJ
Synchronization: NTP primary (WWVB clock), DECstation/Ultrix
Service area: JvNCnet
Access policy: open access
Contact: Dan Strick (timekeeper@bellcore.com)

rackety.udel.edu (128.4.1.1)
Location: University of Delaware, Newark, DE
Geographic Coordinates: 39:40:48.184N, 75:45:3.067W (GPS WGS84)
Synchronization: NTP V3 primary (GPS clock), Sun IPC/SunOS 4.1.1
Service area: NSFNET, SURA region
Access policy: closed access, except for stratum-2 servers providing
synchronization to local networks of ten or more hosts
Contact: Dave Mills (mills@udel.edu)

shorty.chpc.utexas.edu (129.116.3.5)
Location: UT SYSTEM CHPC, Austin, TX
Synchronization: NTP V3 primary (WWV clock), Sun IPC/SunOS 4.1.1
Service area: NSFNET, THENET region
Access policy: open access
Contact: William L. Jones (jones@chpc.utexas.edu)

suzuki.ccie.utoronto.ca (128.100.49.105) deleted

swisstime.ethz.ch (129.132.1.160)
Location: Swiss Fed. Inst. of Technology, CH 8092 Zurich, Switzerland
Geographic Coordinates: 47:23N, 8:32E
Synchronization: NTP primary (DCF77 clock), DS5500/Unix
Service area: Switzerland/Europe
Access policy: open access
Contact: Adam Feigin (time@swisstime.ethz.ch)

tick.usask.ca (128.233.3.100)
Location: University of Saskatchewan, Saskatoon, SK, Canada
Geographic Coordinates: 52:08:01N, 106:38:11W
Synchronization: NTP V3 Primary (GOES clock), VAX/Unix
Service area: SASK#net, CA*net, Canada
Access policy: open access, prior arrangment required
Contact: Glenn Hollinger (glenn@herald.usask.ca)
Note: priority to local regional sites
Note: tick.usask.ca and tock.usask.ca share a single GOES receiver

timer.nta.no (128.39.1.149)
Location: The Research Department of the Norwegian Telecommunications
Administration (NTA-RD), Kjeller, Norway
Synchronization: NTP primary, (NTP clock), Fuzzball (LORAN-C timebase)
Service area: Norway
Access policy: closed access; for use only by prior arrangement
Contact: Terje Hammer (ham@tor.nta.no)

timer.unik.no (128.39.10.149)
Location: UNIK (University Department at Kjeller), Kjeller, Norway
Synchronization: NTP V3 primary, (NTP clock), Fuzzball (cecium timebase)
Service area: Norway
Access policy: open access
Contact: Paal Spilling (paal@tor.nta.no)

tock.usask.ca (128.233.3.101)
Location: University of Saskatchewan, Saskatoon, SK, Canada
Geographic Coordinates: 52:08:01N, 106:38:11W
Synchronization: NTP V3 Primary (GOES clock), VAX/Unix
Service area: SASK#net, CA*net, Canada
Access policy: open access, prior arrangment required
Contact: Glenn Hollinger (glenn@herald.usask.ca)
Note: priority to local regional sites
Note: tick.usask.ca and tock.usask.ca share a single GOES receiver

truechimer.cso.uiuc.edu (192.17.2.40)
Location: University of Illinois, Champaign, IL
Synchronization: NTP V3 primary (WWVB clock), Fuzzball
Service area: CICNET, NSFNET, NCSA region
Access policy: open access, please send a message to notify.
Contact: Paul Pomes (paul-pomes@uiuc.edu)

umd1.umd.edu (128.8.10.1)
Location: University of Maryland, College Park, MD
Synchronization: NTP V3 primary (WWVB clock), Fuzzball
Service area: NSFNET, SURA region
Access policy: closed access, except for stratum-2 servers providing
synchronization to local networks of ten or more hosts
Contact: Louie Mamakos (louie@trantor.umd.edu)

vecrhc1.hpl.hp.com (15.255.60.3)
Location: Hewlett-Packard Laboratorites, Bristol, UK
Synchronization: NTP primary (MSF clock), HP/Unix
Service area: HP corporate
Access policy: closed access; for use only by prior arrangement
Contact: Robert Cole (rhc@hplb.hp.com)

wwvb.isi.edu (128.9.2.129)
Location: USC Information Sciences Institute, Marina del Rey, CA
Geographic Coordinates: 33:58:49N, 118:26:20W (USGS map NAD27)
Synchronization: NTP V3 primary (WWVB clock), Fuzzball
Service area: NSFNET, Los Nettos region
Access policy: open access
Contact: Steve Casner (casner@isi.edu)

wwvb.erg.sri.com (128.18.{3,4,5,6,200}.39)
Location: SRI International, Menlo Park, CA
Synchronization: NTP primary (WWVB clock) Sun/Unix
Service area: NSFNET, BARR Region
Access policy: open access
Contact: Bryan McDonald (bigmac@erg.sri.com)
Note: wwvb.erg.sri.com is a CNAME for (presently) sparkyfs.erg.sri.com

wwvb.sdd.hp.com (15.255.160.64)
Location: Hewlett Packard Co., San Diego, CA
Synchronization: NTP V3 primary (WWVB clock), HP-UX/Unix
Service area: NSFNET, BARR region
Access policy: semi-open access, prior arrangment required
Contact: Ken Stone (timekeeper@sdd.hp.com)
Note: Used for code development

Secondary Servers
-----------------
ashe.cs.tcd.ie (134.226.32.17)
Location: Trinity College, Dublin, Ireland
Synchronisation: NTP secondary (stratum 2), DEC5810
Service area: Ireland, UK
Access policy: open access
Contact: time@maths.tcd.ie
Note: salmon.maths.tcd.ie (134.226.81.11), ashe.cs.tcd.ie
(134.226.32.17) and lib1.tcd.ie (134.226.1.24)peer together over local
area net, and one or more usually run at stratum 2. It is normally
sufficient just to pick one machine to peer with.

augean.ua.oz.au (129.127.4.2)
Location: University of Adelaide, South Australia
Synchronization: NTP secondary (stratum 2), Vax-11/780/Unix
Service area: AARNet
Access policy: open access
Contact: Tarmo Rohtla (tarmo@augean.ua.oz.au)

beno.css.gov (140.162.1.5)
Location: Center for Seismic Studies, Arlington, VA
Geographic Coordinates: 38:53:50N, 77:04:34W
Synchronization: NTP V3 secondary (stratum 2), Sun-4/260
Service area: NSFNET, SURA region
Access policy: open access
Contact: David S. Comay (dsc@seismo.css.gov)

beowulf.ucsd.edu (132.239.51.6)
Location: UCSD Computer Science & Engineering Department, San Diego, CA
Synchronization: NTP secondary (stratum 2), Sun/Unix
Service area: CERFNET; NSFNET, SDSC region
Access policy: open access, please send a message to notify.
Contact: timekeeper@cs.ucsd.edu

bernina.ethz.ch (129.132.1.170)
Location: Swiss Fed. Inst. of Technology, CH 8092 Zurich, Switzerland
Geographic Coordinates: 47:23N, 8:32E
Synchronization: NTP secondary (stratum 2), DS5840/Unix
Service area: Switzerland/Europe
Access policy: open access
Contact: Peter Lamb/Andy Karrer (time@iis.ethz.ch)

chime1.surfnet.nl (192.65.81.6)
Location: SURFnet bv, Utrecht, The Netherlands
Synchronisation: NTP secondary (Stratum 2), Sun Sparc
Service area: The Netherlands
Access policy: open access
Contact: netmaster@surfnet.nl
Note: Chime1.surfnet.nl is peering with chime2.surfnet.nl (192.87.36.2),
which is located in Delft, The Netherlands. Please notify
netmaster@surfnet.nl in case you will start chiming us, so we can put
you on the email notification list, for outages, IP address changes,
becoming a Stratum 1, etc..

clock.bme.unc.edu (152.2.100.32)
Location: University of North Carolina-Chapel Hill, Chapel Hill, NC
Geographic Coordinates: 35:54:19N, 79:03:10W
Synchronization: NTP secondary (stratum 2), DECstation 5000/Ultrix/xntpd
Service area: networks part of the CONCERT regional network
Access policy: open access in service area, others by arrangement
Contact: Christopher Woodbury (woodbury@bmc.unc.edu)
Note: Networks of hosts outside the service area accessing
this system without prior arrangement will be ignored.

clock.psu.edu (128.118.25.3)
Location: Penn State University, University Park, PA
Synchronization: NTP secondary (stratum 2), Sun/Unix
Service area: PREPNET, JvNCnet, PSC region
Access policy: open access
Contact: John Balogh (jdb@ecl.psu.edu)

clock.tricity.wsu.edu (192.31.216.5)
Location: Washington State University Tri-Cities, Richland, Wa
Synchronization: NTP secondary (stratum 2), DS5100/Unix
Service area: NSFNET, NorthWestNet
Access policy: open access
Contact: David Miller (dmiller@dragon.tricity.wsu.edu)
Note: clock.tricity.wsu.edu is a CNAME for meson.tricity.wsu.edu

* delphi.cs.ucla.edu (131.179.128.36)
Location: UCLA Computer Science Department, Los Angeles, CA
Geographic Coordinates: 34:04:08N, 118:26:31W
Synchronization: NTP secondary (stratum 2), Sun/SunOS
Service area: NSFNET, SDSC region
Access policy: open access
Contact: Chinson Yi (chinson@cs.ucla.edu)

constellation.ecn.uoknor.edu (129.15.22.8)
Location: University of Oklahoma, Norman, Oklahoma, USA
Synchronization: NTP secondary (stratum 2), Mac Quadra 700/A/UX 3.0
Service Area: Midnet
Access policy: open access
Contact: Robert Shull (rob@mailhost.ecn.uoknor.edu)

eagle.tamu.edu (128.194.3.93)
Location: Texas A&M Academic Computing Services, College Station, TX
Synchronization: NTP secondary (stratum 2, ver. 3), DECstation 5000-
133/Ultrix
Service area: NSFNET, SESQUI region, THEnet
Access policy: open access
Contact: Bryan A. Ignatow, Academic Computing Services, ignatow@tamu.edu

falcon.tamu.edu (128.194.3.100) deleted; see eagle.tamu.edu
(128.194.3.93), zeus.tamu.edu (128.194.3.85)

fartein.ifi.uio.no (129.240.102.2)
Location: University of Oslo, Norway
Geographic Coordinates: 59:56:32N, 10:43:22E
Synchronization: NTP secondary (stratum 2), VAXstation/Ultrix
Service area: NORDUnet
Access policy: open access
Contact: Anders Ellefsrud, Ole Bjorn Hessen (timekeeper@ifi.uio.no)
Note: Other stratum 2 servers in the Oslo area available on request

fuzz.psc.edu (192.5.146.42)
Location: PSC Supercomputer Center, Pittsburgh, PA
Synchronization: NTP V3 secondary (stratum 2), Fuzzball
Service area: NSFNET, PSC region
Access policy: open access
Contact: Eugene Hastings (hastings@morgul.psc.edu)

fuzz.sura.net (192.80.214.42)
Location: SURAnet, College Park, MD
Synchronization: NTP V3 secondary (stratum 2), Fuzzball
Service area: NSFNET, SURAnet region
Access policy: open access
Contact: Brad Passwaters (timekeeper@sura.net)
Note: formerly known as clock.umd.edu (192.41.177.92); fuzz.sura.net has
a CNAME of clock.sura.net

gazette.bcm.tmc.edu (128.249.2.2)
Location: Baylor College of Medicine, Houston, Tx
Synchronization: NTP secondary (stratum 2), Solbourne-OS/MP 4.0C
Service area: NSFNET, SESQUI region
Access policy: open access
Contact: Stan Barber (sob@tmc.edu)

george.jpl.nasa.gov (128.149.2.1)
Location: Jet Propulsion Laboratory, Pasadena, CA
Synchronization: NTP secondary (stratum 2), Sun/SunOS 4.1
Service area: NSFNET, Los Nettos region, NASA NSN
Access policy: open access
Contact: Steve Groom (stevo@elroy.jpl.nasa.gov)
Note: select one of (george.jpl.nasa.gov, jane.jpl.nasa.gov) to equalize
load

gus.ecn.purdue.edu (128.46.129.79)
Location: Purdue University Engineering Computer Network, West
Lafayette, IN
Synchronization: NTP secondary (stratum 2), Sun/Unix
Service area: NSFNET, CICNET area
Access policy: open access
Contact: Jeff Schwab (jrs@ecn.purdue.edu)

gweedo.tamu.edu (128.194.3.112) deleted; see eagle.tamu.edu
(128.194.3.93), zeus.tamu.edu (128.194.3.85)

heechee.meediv.lanl.gov (128.165.196.2)
Location: Los Alamos National Laboratory, Los Alamos, NM
Synchronization: NTP secondary (stratum 2), VAXStation 4000-VLC
VMS+Multinet
Service area: ESNET, TECHNET area
Access policy: open access
Contact: Jim A. Whitfill whitfill@meediv.lanl.gov

jane.jpl.nasa.gov (128.149.2.7)
Location: Jet Propulsion Laboratory, Pasadena, CA
Synchronization: NTP secondary (stratum 2), Sun/SunOS 4.1
Service area: NSFNET, Los Nettos region, NASA NSN
Access policy: open access
Contact: Steve Groom (stevo@elroy.jpl.nasa.gov)
Note: select one of (george.jpl.nasa.gov, jane.jpl.nasa.gov) to equalize
load

kuhub.cc.ukans.edu (129.237.32.1)
Location: Kansas University Computer Center, Lawrence, Kansas 66047, USA
Geographic Coordinates: 39:56N, 95:14W
Synchronization: NTP secondary (stratum 2), VAX 9210/VMS
Service Area: Midnet, NSFnet
Access policy: open access
Contact: Craig Paul (paul@kuhub.cc.ukans.edu)

lane.cc.ukans.edu (129.237.32.2)
Location: Kansas University Computer Center, Lawrence, Kansas 66047, USA
Geographic Coordinates: 39:56N, 95:14W
Synchronization: NTP secondary (stratum 2), VAXstation 3100/VMS
Service Area: Midnet, NSFnet
Access policy: open access
Contact: Craig Paul (paul@lane.cc.ukans.edu)

larry.mcrcim.mcgill.edu (132.206.1.1)
Location: McGill RCIM, Montreal, QC, Canada
Synchronization: NTP secondary (stratum 2), VAX-11/750/4.3BSD
Service area: CAnet, RISQ region
Access policy: open access
Contact: Mike Parker (mouse@larry.mcrcim.mcgill.edu)

lib1.tcd.ie (134.226.1.24)
Location: Trinity College, Dublin, Ireland
Synchronisation: NTP secondary (stratum 2), DEC5000/200
Service area: Ireland, UK
Access policy: open access
Contact: time@maths.tcd.ie
Note: salmon.maths.tcd.ie (134.226.81.11), ashe.cs.tcd.ie
(134.226.32.17) and lib1.tcd.ie (134.226.1.24)peer together over local
area net, and one or more usually run at stratum 2. It is normally
sufficient just to pick one machine to peer with.

libra.rice.edu (128.42.1.64)
Location: Rice University, Houston, TX
Synchronization: NTP secondary (stratum 2), Fuzzball
Service area: NSFNET, SESQUI region
Access policy: open access
Contact: Farrell Gerbode (gerbode@rice.edu)
Note: this server has not been heard from for many months [dlm]

nic.near.net (192.52.71.4)Location: Cambridge, MA
Synchronization: NTP secondary (stratum 2), Sun/Unix
Service area: NEARnet
Access policy: open access
Contact: NEARnet Operations (nearnet-ops@nic.near.net

noc.near.net (192.52.71.21)
Location: Cambridge, MA
Synchronization: NTP secondary (stratum 2), Sun/Unix
Service area: NEARnet
Access policy: open access
Contact: NEARnet Operations (nearnet-ops@nic.near.net

ntp.olivetti.com (129.189.134.11, 129.189.134.6)
Location: Olivetti ATC, Cupertino, CA
Synchronization: NTP secondary (stratum 2), VAX/Unix
Service area: Alternet
Access policy: open access
Contact: Jerry Aguirre (jerry@olivetti.com)

ntp.univ-lyon1.fr (134.214.100.25)
Location: INSA/GRASP, Lyon, France
Synchronization: NTP V3 secondary (stratum 2), IBM RS/6000
Service area: France, Switzerland, Italy, Europe
Access policy: open access
Contact: Christophe.Wolfhugel@grasp.insa-lyon.fr
Note: consult DNS to get host address, ntp is an alias.
Note: we would appreciate getting a little note if you make regular use
of this server, so that we can put you on our NTP mailing-list.

ntp0.cornell.edu (192.35.82.50)
Location: Cornell University, Ithaca, NY
Synchronization: NTP secondary (stratum 2), Sun/Unix
Service area: NSFNET, NYSER region
Access policy: open access
Contact: Donald Redick <dredick@nmc.cit.cornell.edu>

* ntp1.cs.ucla.edu (131.179.128.2) deleted; see delphi.cs.ucla.edu

* ntp2.cs.ucla.edu (131.179.128.5) deleted; see delphi.cs.ucla.edu

louie.udel.edu (128.175.1.3)
Location: University of Delaware, Newark, DE
Synchronization: NTP V3 secondary (stratum 2), Vax-11/780/Unix
Service area: NSFNET, SURA region
Access policy: open access
Contact: Dave Mills (mills@udel.edu)

meevax.meediv.lanl.gov (128.165.196.1)
Location: Los Alamos National Laboratory - Los Alamos, NM
Synchronization: NTP secondary (stratum 2), VAX 6320/VMS
Service area: ESNET, TECHNET area
Access policy: open access
Contact: Jim A. Whitfill whitfill@meediv.lanl.gov

molecules.ecn.purdue.edu (128.46.129.82)
Location: Purdue University Engineering Computer Network, West
Lafayette, IN
Synchronization: NTP secondary (stratum 2), Sun/Unix
Service area: NSFNET, CICNET area
Access policy: open access
Contact: Jeff Schwab (jrs@ecn.purdue.edu)

* ntp.cox.smu.edu (129.119.80.126)
Location: Cox School of Business, Southern Methodist University, Dallas,
TX
Synchronization: NTP V3 secondary (stratum 2), DECstation 5000/125-
Ultrix 4.3
Service Area: NSFNET, SESQUI region
Access policy: open access
Contact: John Meaders (johnm@mail.cox.smu.edu)
Note: Please send e-mail letting us know you will be using
ntp.cox.smu.edu. ntp.cox.smu.edu is a CNAME for nyse.cox.smu.edu.

ntp.adelaide.edu.au (129.127.40.3)
Location: University of Adelaide, South Australia
Synchronization: NTP V3 secondary (stratum 2), DECsystem 5000/25 Unix
Service area: AARNet
Access policy: open access
Contact: Mark Prior (mrp@itd.adelaide.edu.au)

ntps2-0.uni-erlangen.de (131.188.31.1)
Location: University Erlangen-Nuernberg, D-W8520 Erlangen, FRG
Synchronization: NTP V3 secondary (stratum 2), Sun 4/470/SunOS4.1.1
Service area: Germany/Europe
Access policy: open access
Contact: Frank Kardel, Rainer Pruy (time@informatik.uni-erlangen.de)

ntp-0.cso.uiuc.edu (128.174.5.50)
Location: Champaign, IL
Synchronization: NTP secondary (stratum 2), VAX-3500/Unix
Service area: CICNET, NSFNET, NCSA region
Access policy: open access, please send a message to notify.
Contact: Paul Pomes (paul-pomes@uiuc.edu)
Note: select one of (ntp-0.cso.uiuc.edu, ntp-1.cso.uiuc.edu, ntp-
2.cso.uiuc.edu) to equalize load
Note: consult DNS to verify host address

ntp-1.cso.uiuc.edu (128.174.5.3)
Location: Champaign, IL
Synchronization: NTP secondary (stratum 2), IBM-RS6000/540
Service area: CICNET, NSFNET, NCSA region
Access policy: open access, please send a message to notify.
Contact: Paul Pomes (paul-pomes@uiuc.edu)
Note: select one of (ntp-0.cso.uiuc.edu, ntp-1.cso.uiuc.edu, ntp-
2.cso.uiuc.edu) to equalize load

ntp-2.cso.uiuc.edu (128.174.5.58)
Location: Champaign, IL
Synchronization: NTP secondary (stratum 2), VAX-3500/Unix
Service area: CICNET, NSFNET, NCSA region
Access policy: open access, please send a message to notify.
Contact: Paul Pomes (paul-pomes@uiuc.edu)
Note: select one of (ntp-0.cso.uiuc.edu, ntp-1.cso.uiuc.edu, ntp-
2.cso.uiuc.edu) to equalize load

orion.ecn.uoknor.edu (129.15.24.31) changed to
constellation.ecn.uoknor.edu

salmon.maths.tcd.ie (134.226.81.11)
Location: Trinity College, Dublin, Ireland
Synchronisation: NTP secondary (stratum 2), MIPS Magnum
Service area: Ireland, UK
Access policy: open access
Contact: time@maths.tcd.ie
Note: salmon.maths.tcd.ie (134.226.81.11), ashe.cs.tcd.ie
(134.226.32.17) and lib1.tcd.ie (134.226.1.24)peer together over local
area net, and one or more usually run at stratum 2. It is normally
sufficient just to pick one machine to peer with.

simvax.meediv.lanl.gov (128.165.196.2) changed to
heechee.meediv.lanl.gov

* sundial.columbia.edu (128.59.40.142)
Location: Morningside Campus, Columbia University, New York, NY
Synchronization: NTP V3 secondary (stratum 2), Sun4/75
Service area: PSInet
Access policy: open access
Contact: Margarita Suarez <marg@columbia.edu>

sirius.ucs.adelaide.edu.au (129.127.40.3) changed to ntp.adelaide.edu.au

tick.cs.unlv.edu (131.216.16.9)
Location: UNLV Computer Science Department, Las Vegas, NV
Synchronization: NTP V3 secondary (stratum 2), Mips/Unix
Service area: NSFNET, SDSC region
Access policy: open access
Contact: Greg Wohletz <greg@cs.unlv.edu>
Note: select one of (tick.cs.unlv.edu, tock.cs.unlv.edu) to equalize
load
Note: tick.cs.unlv.edu is a CNAME for (currently) elmore.cs.unlv.edu

* timeserver.cs.umb.edu (158.121.104.2)
Location: University of Massachusetts, Boston, MA
Synchronization: NTP secondary (stratum 2), Dec/Ultrix
Service area: NEARNET, (and anyone else who would like it)
Access policy: open access
Primary Contact: John Rouillard (rouilj@cs.umb.edu)
Secondary Contact: Rick Martin (rickm@cs.umb.edu)

timeserver.cs.umb.edu (192.12.26.23)
Location: University of Massachusetts, Boston, MA
Synchronization: NTP secondary (stratum 2), Sun/Unix
Service area: NEARNET (and anyone else who would like it)
Access policy: open access
Primary Contact: John Rouillard (rouilj@cs.umb.edu)
Secondary Contact: Rick Martin (rickm@cs.umb.edu)

timex.cs.columbia.edu (128.59.16.20)
Location: Columbia University Computer Science Department, New York
City, NY
Synchronization: NTP secondary (stratum 2), Sun/Unix
Service area: PSINET; NSFNET, NYSER region
Access policy: open access, authenticated NTP (DES/MD5) available
Contact: Alexander Dupuy <timekeeper@cs.columbia.edu>
Note: IP addresses are subject to change; please use DNS

tmc.edu (128.249.1.1)
Location: Baylor College of Medicine, Houston, Tx
Synchronization: NTP secondary (stratum 2), Sun/SunOS 4.1
Service area: NSFNET, SESQUI region
Access policy: open access
Contact: Stan Barber (sob@tmc.edu)

tock.cs.unlv.edu (131.216.18.4)
Location: UNLV Computer Science Department, Las Vegas, NV
Synchronization: NTP V3 secondary (stratum 2), NeXT/Mach
Service area: NSFNET, SDSC region
Access policy: open access
Contact: Greg Wohletz <greg@cs.unlv.edu>
Note: select one of (tick.cs.unlv.edu, tock.cs.unlv.edu) to equalize
load
Note: tock.cs.unlv.edu is a CNAME for (currently) little-
walter.cs.unlv.edu

wuarchive.wustl.edu (128.252.135.4)
Location: Washington University, St. Louis, Missouri, USA
Synchronization: NTP secondary (stratum 2), DECstation 5000/Ultrix
Service Area: Midnet
Access policy: open access
Contact: Chris Myers (chris@wupost.wustl.edu)

yoyo.aarnet.edu.au (129.127.40.4)
Location: The University of Adelaide, Adelaide, South AUSTRALIA
Synchronization: NTP secondary (stratum 2), Sun-3/60/Unix
Service Area: AARNet
Access policy: open access
Contact: Mark Prior <mrp@itd.adelaide.edu.au>

zeus.tamu.edu (128.194.3.85)
Location: Texas A&M Academic Computing Services, College Station, TX
Synchronization: NTP secondary (stratum 2, ver. 1), VAX 9000-210/VMS
Service area: NSFNET, SESQUI region, THEnet
Access policy: open access
Contact: Bryan A. Ignatow, Academic Computing Services, ignatow@tamu.edu

========================================================================

Serial Timecode Formats

Following are examples of the serial timecode formats used by the
various manufacturers as given in the instruction manauals. These
examples are intended only for illustration and not as the basis of
system design. The following symbols are used to identify the timecode
character that begins a subfield. The values given after this symbol
represent the character offset from the beginning of the timecode
string.

C    on-time character (start bit)
T    time of day
D    day of year or month/day
A    alarm indicator (format specific)
Q    quality indicator (format specific)

In order to promote uniform behavior in the various implementations, it
is useful to have a common interpretation of alarm conditions and signal
quality. When the alarm indicator it on, the receiver is not operating
correctly or has never synchronized to the broadcast signal. When the
alarm indicator is off and the quality indicator is on, the receiver has
synchronized to the broadcast signal, then lost the signal and is
coasting on its internal oscillator.

Spectracom 8170 and Netclock/2 WWV Synchonized Clock (format 0)
"<cr><lf>i  ddd hh:mm:ss  TZ=zz<cr><lf>"
 C       A  D   T

     poll: "T"; offsets: T = 7, D = 3, A = 0, Q = none
     i = synchronization flag (" " = in synch, "?" = out synch)
     ddd = day of year
     hh:mm:ss = hours, minutes, seconds
     zz = timezone offset (hours from UTC)

     note: alarm condition is indicated by other than " " at A, which
     occurs during initial synchronization and when received signal has
     been lost for about ten hours

     example: "   216 15:36:43  TZ=0"
               A  D   T

Netclock/2 WWV Synchonized Clock (format 2)

"<cr><lf>iqyy ddd hh:mm:ss.fff ld"
 C       AQD      T

     poll: "T"; offsets: T = 9, D = 2, A = 0, Q = 1
     i = synchronization flag (" " = in synch, "?" = out synch)
     q = quality indicator (" " = locked, "A"..."D" = unlocked)
     yy = year (as broadcast)
     ddd = day of year
     hh:mm:ss.fff = hours, minutes, seconds, milliseconds
     l = leap-second warning ("L" indicates leap at end of month)
     d = daylight time indicator (see manual)

     note: alarm condition is indicated by other than " " at A, which
     occurs during initial synchronization and when received signal has
     been lost for about ten hours; unlock condition is indicated by
     other than " " at Q

     example: "   216 15:36:43.640 D"
               AQ D   T

TrueTime 468-DC Satellite Synchronized Clock

"<cr><lf><^a>ddd:hh:mm:ssq<cr>"
            D   T       QC

     poll: none; offsets: T = 4, D = 0, A = 12, Q = 12
     hh:mm:ss = hours, minutes, seconds
     q = quality/alarm indicator (" " = locked, "?" = alarm)

     note: alarm condition is indicated by "?" at A, which occurs during
     initial synchronization and when received signal is lost for an
     extended period; unlock condition is indicated by other than " " at
     Q

     example: "216:15:36:43 "
               D   T       Q

Heath GC-1000 Most Accurate Clock (WWV/H)

"<cr>hh:mm:ss.f     dd/mm/yy<cr>"
 C   T        A     D

     poll: none; offsets: T = 0, D = 15, A = 9, Q = none
     hh:mm:ss = hours, minutes, seconds
     f = deciseconds ("?" when out of spec)
     dd/mm = day, month
     yy = year (from DIPswitches)
     note: 0?:??:??.? is displayed before synch is first established and
     hh:mm:ss.? once synch is established and then lost again for about
     a day

     example: "15:36:43.6     04/08/91"
          T        A     D

PST/Traconex 1020 Time Source (WWV/H) (firmware revision V4.01)

"ahh:mm:ss.fffs<cr>" "yy/dd/mm/ddd<cr>" "frdzycchhSSFTttttuuxx<cr>"
  T            C                D                   A   Q

     poll: "QTQDQM"; offsets: T = 1, D = 24, Q = 41, A = 37
     a = AM/PM indicator (" " for 24-hour mode)
     hh:mm:ss.fff = hours, minutes, seconds, milliseconds
     s = daylight-saving indicator (" " for 24-hour mode)
     yy = year (from DIPswitches)
     dd/mm/ddd = day of month, month, day of year
     f = frequency enable (O = all frequencies enabled)
     r = baud rate (3 = 1200, 6 = 9600)
     d = features indicator (@ = month/day display enabled)
     z = time zone (0 = UTC)
     y = year (5 = 91)
     cc = WWV propagation delay (52 = 22 ms)
     hh = WWVH propagation delay (81 = 33 ms)
     SS = status (80 or 82 = operating correctly)
     F = current receive frequency (4 = 15 MHz)
     T = transmitter (C = WWV, H = WWVH)
     tttt = time since last update (0000 = minutes)
     uu = flush character (03 = ^c)
     xx = 94 (unknown) (firmware revision X4.01.999 only)

     note: alarm condition is indicated by other than "8" at A, which
     occurs during initial synchronization and when received signal is
     lost for an extended periodunlock condition is indicated by other
     than "0000" in the tttt subfield at Q

     example: " 15:36:43.640  91/08/04/216 O3@055281824C00000394"

========================================================================

Timecode Receivers

Following is a list of radio timecode receivers currently on the market.
These devices are attached via a serial asynchronous line, which is used
to send poll messages and receive responses. Unless indicated otherwise,
the accuracy of these receivers is in the range of a millisecond or two
relative to UTC when corrected for the receiver internal delay and
signal propagation delay from the transmitter to the receiver. Prices
are taken from the manufacturer's current literature.

* Model 2201 GPS Receiver Mainframe with Output Interface Option and
RS232 I/O Interface Option (incl. antenna) ($12,240)
Austron, Inc.
P.O. Box 14766
Austin, TX 78761
(512) 251-2313

     This is a UHF receiver and decoder for satellites of the Global
     Positioning System. It provides complete decoding of the navigation
     message, together with an accuracy of 100 ns relative to UTC(GPS)
     at the 1-pps output. This receiver provides the year as broadcast
     (using special commands), but no leap-second warning. The antena
     may be mounted up to several hundred feet from the receiver. Note:
     There are serious deficiencies in the design of early production
     models which preclude reliable computer control of this radio. The
     manufacturer has upgraded to the 2201A model.

* Model bc700LAN GPS Time Server (price unknown)
Bancomm Division of Datum, Inc.
6541 Via del Oro
San Jose, CA 95119
(408) 578-4161 FAX (408) 578-4165

     This is a UHF receiver and decoder for satellites of the Global
     Positioning System. It provides an accuracy of 100 ns relative to
     UTC(GPS) at the 1-pps output and an NTP accuracy of 1 ms. It
     consists of a GPS receiver and NTP server integrated in a single
     suitcase-size package. This receiver provides the year as broadcast
     (using special commands), but no leap-second warning. The antenna
     may be mounted up to 50' from the receiver. Note: This receiver may
     no longer be in production. See the following entry for an
     alternative.

* Model TYMESERVE 2000 LAN Time Server (incl. antenna) ($8000)
Bancomm Division of Datum, Inc.
6541 Via del Oro
San Jose, CA 95119
(408) 578-4161 FAX (408) 578-4165

     This is an integrated NTP time server and reference timing source
     for use on an Ethernet. It can be configured to operate with a GPS
     receiver, ACTS telephone or external IRIG-B source. It produces
     IRIG-B, 1-pps and selectable standard frequency outputs. The GPS
     receiver operates with satellites of the Global Positioning System
     and provides a timing accuracy of one millisecond at the Ethernet
     connection. This receiver provides the year as broadcast (using
     special commands), but no leap-second warning. The antenna may be
     mounted up to 1000' from the receiver.

Model ? MSF Synchronized Clock (price unknown)
European Electric Systems, Ltd.
Woodham Mortimer Place, Rectory Lane
Woodham Mortimer, Maldon, Essex. CM9 6SW, United Kingdom
+44 24541 5785, (FAX) +44 24541 5785

     This is a LF receiver for the MSF (Rugby, UK) station. It is
     reported they manufacture a US version for the WWVB station. No
     further information is available.

Model GC-1000 Most Accurate Clock ($350)
Heath Company
Benton Harbor, MI 49022
(616) 925-6000
Note: The Heath Company is no longer in business; however, sombody might
buy the patent and reinvent the beast.

     This is an HF receiver and decoder for the WWV/WWVH stations. It is
     supported (reluctantly) in the Fuzzball operating system. This
     receiver provides the year (from internal DIPswitches), but no
     leap-second warning.

Model GPStar Time and Frequency System ($3,995 incl. antenna)
Odetics Precision Time Division
1515 South Manchester Avenue
Anaheim, CA 92802
(714) 758-0400 FAX (714) 758-8463

     This is a UHF receiver and decoder for satellites of the Global
     Positioning System. It provides an output at 1 pps plus adjustable
     time and frequency outputs. This receiver provides the year as
     broadcast (using special commands), but no leap-second warning. The
     antena may be mounted up to several hundred feet from the receiver.

Model NETCLOCK/2 Computer Clock (incl. 8208 antenna ($1,550)
Spectracom Corporation
101 Despatch Drive
East Rochester, NY 14445
(716) 381-4827

     This is an LF receiver and decoder for the WWVB station and
     replaces the Model 8170 WWVB Synchronized Clock, which sold for
     $2,500. A model for the MSF station is also available. Both are
     supported in the Fuzzball operating system and Unix operating
     system (xntpd). For expected accuracies less than +-10 ms, the 1-
     pps output must be used to fine-tune the indication. This receiver
     provides both the year and leap-second warning as broadcast.

Model 1020 Integrated Time Source ($1,500)
Traconex Corporation
Mike Gerado (213) 724-0450 or Bob Young (714) 632-9510
1140 N. Kramer Blvd., Unit G
Aneheim, CA  92806
(714) 632-9510

     This is an HF receiver and decoder for the WWV/WWVH stations. It is
     supported in the Fuzzball operating system and Unix operating
     system (xntpd). Version 4.01 or later of the clock firmware is
     required. This receiver, formerly marketed by Precision Standard
     Time, is now being marketed by the Traconex Corporation. It is
     reported their assets have been purchased by Meyers Electric. This
     receiver provides the year (from internal DIPswitches), but no
     leap-second warning.

Model 8810 GPS Station Clock (under $10,000)
Trak Systems Division
4726 Eisenhower Blvd.
Tampa, FL 33634-6391
(813) 884-1411 ext 248

     This is a UHF receiver and decoder for satellites of the Global
     Positioning System. It provides RS232 remote control and time
     output accurate to 100 ns. Further information is available from
     the manufacturer.

Model GPS-DC GPS Synchronized Clock MK III (incl. antenna) ($9,750)
TrueTime Division, Kinemetrics
3243 Santa Rosa Avenue, Santa Rosa, CA 95407
(707) 528-1230

     This is a UHF receiver and decoder for satellites of the Global
     Positioning System and replaces the original Model GPS-DC GPS
     Synchronized Clock, which sold for $12,500. It provides complete
     decoding of the navigation message, together with an accuracy of
     250 ns relative to UTC(GPS) at the 1-pps output. TrueTime decoder
     formats are supported in the Fuzzball operating system and Unix
     operating system (xntpd). This receiver provides the year as
     broadcast (using special commands), but no leap-second warning.

Model GPS-PC PC Card GPS Synchronized Generator ($3,400 incl. antenna)
TrueTime Division, Kinemetrics
3243 Santa Rosa Avenue, Santa Rosa, CA 95407
(707) 528-1230

     This is a plug-in card for the IBM PC and compatibles. It provides
     time in milliseconds through days in parallel BCD format.

Model 468-DC MK III GOES Satellite Synchronized Clock ($4,925) TrueTime
Division, Kinemetrics
3243 Santa Rosa Avenue, Santa Rosa, CA 95407
(707) 528-1230

     This is a UHF receiver and decoder for the GOES satellite and
     replaces the original Model GPS-DC GPS Synchronized Clock, which
     sold for $5,800 (incl. antenna). TrueTime decoder formats are
     supported in the Fuzzball operating system and Unix operating
     system (xntpd). This receiver provides neither the year nor leap-
     second warning.

Model 60-DC WWVB Synchronized Clock (incl. antenna) ($2,625)
TrueTime Division, Kinemetrics
3243 Santa Rosa Avenue, Santa Rosa, CA 95407
(707) 528-1230

     This is an LF receiver and decoder for the WWVB station. TrueTime
     decoder formats are supported in the Fuzzball operating system and
     Unix operating system (xntpd). This receiver provides neither the
     year nor leap-second warning.

Model LF-DC MSF/DCF77 Synchronized Clock (incl. antenna) ($3,100)
TrueTime Division, Kinemetrics
3243 Santa Rosa Avenue, Santa Rosa, CA 95407
(707) 528-1230

     This is an LF receiver and decoder for the MSF station (Rugby, UK)
     and DCF77 station (Mainflingen, Germany). TrueTime decoder formats
     are supported in the Fuzzball operating system and Unix operating
     system (xntpd). This receiver provides neither the year nor leap-
     second warning.

Model OM-DC OMEGA Synchronized Clock (incl. antenna and preamp) ($3,900)
TrueTime Division, Kinemetrics
3243 Santa Rosa Avenue, Santa Rosa, CA 95407
(707) 528-1230

     This is a VLF receiver and decoder for the OMEGA stations. TrueTime
     decoder formats are supported in the Fuzzball operating system and
     Unix operating system (xntpd). This receiver provides neither the
     year nor leap-second warning.

8101 Automated Computer Time Service (ACTS)
Time and Frequency Division, National Bureau of Standards
US Department of Commerce, Gaithersburg, MD 20899

     This is a package of C software on diskette for the IBM Personal
     Computer. It can be used to call a special NBS number using either
     300-Hz or 1200-Hz modem and set the computer clock. The latest
     version has been adapted to run on Sun/Unix workstations. This
     service provides the year and leap-second warning.

========================================================================

* Precision Oscillators and Timing Receivers

For accuracies better than a millisecond or two, a precision oscillator
and means of calibration relative to UTC are usually required. This can
be accomplished with a cesium or rubidium standard, which is
periodically calibrated with a portable standard or physically moved to
a source of standard time, such as U.S. Naval Observatory in Washington,
DC, or NIST in Boulder, CO.

Between calibrations it is usually necessary to use some kind of radio
or satellite service, such as LORAN-C or GPS, to monitor the oscillator
and calibrate its particular inherent frequency offet. None of the
devices listed produce a serial timecode which can be read by a
computer, but all provide outputs that can be used with appropriate
computer interfaces to fine-tune the indication from a timecode
receiver.

Note that, although several Fuzzball time servers continue to operate in
the Internet, that operating system should be considered obsolete. The
newer refinements of the NTP Version 3 daemon xntp3 include provisions
to discipline the onboard frequency source to an external source of
seconds pulses such as produced by most of the following devices.

* Model 5071A Cesium Beam Standard ($55,100 with clock and power supply)
Hewlett Packard, Co.
19310 Pruneridge Avenue
Cupertino, CA 95014

     This is a cesium-beam primary standard oscillator/clock with long-
     term stability better than 7x10^-13 (about 60 ns per day). It
     produces various outputs which can be used to provide a precise
     frequency and time reference when used in conjunction with a
     timecode receiver. Used to stabilize frequency with the NTP local-
     clock algorithms, a time server will ensure accuracy to a
     millisecond even after all contact with a reference source has been
     lost well over the expected life of the beam tube, which is about
     ten years. The frequency and time outputs of this device are
     supported in the Fuzzball operating system and xntp3 distribution.

* Model 5065A Rubidium Frequency Standard ($49,000 with clock and power
supply)
Hewlett Packard, Co.
19310 Pruneridge Avenue
Cupertino, CA 95014

     This is a rubidium-vapor resonance cell secondary standard
     oscillator/clock with long-term stability better than 2x10^-12
     (about 170 ns per day). It produces various outputs which can be
     used to provide a precise frequency and time reference when used in
     conjunction with a timecode receiver. Used to stabilize frequency
     with the NTP local-clock algorithms, a time server will ensure
     accuracy to a millisecond even after all contact with a reference
     source has been lost well over a year. The frequency and time
     outputs of this device are supported in the Fuzzball operating
     system and xntp3 distribution.

* Model 105B Quartz Oscillator ($9,050)
Hewlett Packard, Co.
19310 Pruneridge Avenue
Cupertino, CA 95014

     This is an oven-stabilized quartz oscillator with stability better
     than 1x10^-10 (about 9 us per day). It produces various outputs
     which can be used to provide a precise frequency reference when
     used in conjunction with a timecode receiver. Used to stabilize
     frequency with the NTP local-clock algorithms, a time server will
     ensure accuracy to a millisecond even after all contact with a
     reference source has been lost over three months. The frequency
     output of this device is supported in the Fuzzball operating system
     and xntp3 distribution.

Model OCXO-107 Oven-Compensated Quartz Oscillator ($700)
ISOTEMP Research, Inc.
Charlottesville, VA

     This is an oven-stabilized quartz oscillator with stability better
     than 1x10^-8 (about 0.9 ms per day). It produces a 5-MHz output
     which can be used to provide a precise frequency reference when
     used in conjunction with a timecode receiver. Used to stabilize
     frequency with the NTP local-clock algorithms, a time server will
     ensure accuracy to a millisecond even after all contact with a
     reference source has been lost over one day. The frequency output
     of this device is supported in the Fuzzball operating system.

* Model 2000 LORAN-C Timing Receiver ($20,000)
Austron, Inc.
P.O. Box 14766
Austin, TX 78761
(512) 251-2313

     This is a LORAN-C receiver with stability and accuracy determined
     by the propagation characteristics of the LORAN-C signal. It
     produces various outputs which can be used to provide a precise
     frequency and time reference when used in conjunction with a
     timecode receiver. When used with domestic U.S. LORAN-C chains, it
     provides accuracies in the order of 100 ns. The frequency and time
     outputs of this device are supported in the Fuzzball operating
     system and xntp3 distribution.

========================================================================

Timecode Transmitters, Frequencies and Geographic Coordinates

Call   Location          Frequencies         Coordinates
------------------------------------------------------------------------
WWV  Ft. Collins, CO     2.5/5/10/15/20 MHz  40:40:49.0N 105:02:27.0W
WWVB Ft. Collins, CO     60 kHz              40:40:28.3N 105:02:39.5W
WWVL Ft. Collins, CO     20 kHz (silent key) 40:40:51.3N 105:03:00.0W
WWVH Kauai, HI           2.5/5/10/15 MHz     21:59:26.0N 159:46:00.0W
CHU  Ottawa, CA          3330/7335/14670 kHz 45:18N 75:45N
DCF77 Mainflingen, DE    77.5 kHz            50:01N 9:00E
MSF  Rugby, UK           60 kHz              52:22N 1:11W
TDF  Allouis, FR         162 kHz             47:10N, 2:12E

Oddball coordinates (note that one second of latitude is about 31
meters)

Newark Hall         39:40:40N, 75:44:57W (survey NAD27)
121 Evans Hall      39:40:48.184N, 75:45:03.067W (GPS WGS84)
121 Evans Hall      39:40:48.462N, 75:45:04.334W (GPS WGS84)
Christiana Commons  39:41:26N, 75:45:23W (survey NAD27)
W3HCF Backroom      39:42:00N, 75:46:55W (USGS map NAD27)
Marina del Rey, CA  33:58:49N, 118:26:20W

Control Point

NAD27     39:40:48  NAD83     39:40:48.39725
          75:45:05            75:45:03.76078

Great-circle distance and bearing computation

#define R 6371.2              /* radius of the Earth (km) */
#define PI 3.141592653589     /* the real thing */
#define D2R PI/180            /* degrees to radians */
#define VOFL 2.9979250e8      /* velocity of light (m/s)*/
#define hF 320                /* nominal height of F layer (km) */
#define MINBETA 5.*D2R        /* min elevation angle (rad) */

double lat1;                  /* transmitter latitude (deg N) */
double lon1;                  /* transmitter longitude (deg W) */
double lat2;                  /* receiver latitude (deg N) */
double lon2;                  /* receiver longitude (deg W) */
double d;                     /* great-circle distance (rad) */
double theta;                 /* hour angle (rad) */
int hop;                      /* number of ray hops */
double beta;                  /* elevation angle (rad) */
double delay;                 /* path delay (ms) */
double dhop;                  /* hop angle/2 (rad) */

     lat1 = lat1*D2Rlon1 = lon1*D2R;
     lat2 = lat2*D2Rlon2 = lon2*D2R;
     theta = lon2-lon1;
     if (theta >= PI) theta = theta-2*PI;
     if (theta <= -PI) theta = theta+2*PI;
     d = acos(sin(lat1)*sin(lat2)+cos(lat1)*cos(lat2)*cos(theta));
     if (d < 0) d = PI+d;
     hop = d/(2*acos(R/(R+hF)));
     beta = 0;
     while (beta < MINBETA) {
          hop = hop+1dhop = d/(hop*2);
          beta = atan((cos(dhop)-R/(R+hF))/sin(dhop));
          }
     delay = 2*hop*sin(dhop)*(R+hF)/cos(beta)/VOFL*1e6;

========================================================================

Appendix. Time Synchronization Stations Outside the U.S.

Editor's note: The following information is provided as an aid in
developing timecode software for primary time servers using various
national standards dissemination media. No claim is made on correctness
other than by the authors listed.

Information included in this version applies to DCF77 (Germany), MSF
(United Kingdom) and TDF (France).

------------------------------------------------------------------------

          Time and Standard Frequency Station DCF77 (Germany)

(Original in German available from the address below. Translation errors
courtesy of Peter Lamb, Swiss Fed. Inst. of Technology).

Physikalisch-Technische Bundesanstalt (PTB) Braunschweig, Febuar 1984
Lab 1.21
Bundesalle 100
D-3300 Braunschweig

Legal basis and responsibility for the transmissions from DCF77

The 1978 law on time standards defines legal time in Germany on the
basis of Coordinated World Time (UTC) and gives the PTB responsibility
for the keeping and broadcasting of legal time. As well as this, the
time standards law empowers the Federal government to issue regulations
for the introduction of Summer Time.

Legal time in the FRG is either Middle European Time (MEZ - German
abbreviation) or, in case of its introduction Middle European Summer
Time (MESZ). The following relationships hold between UTC and MEZ and
MESZ.

     MEZ(D)  = UTC(PTB) + 1h
     MESZ(D) = UTC(PTB) + 2h

Legal time is generated in the PTB Atomic Clock Building in Braunschweig
and it is broadcast mainly through the LF transmitter DCF77 which the
PTB rents from the German Post Office (DBP). The PTB has sole
responsibility for the control of DCF77, while the DBP has
responsibility for the transmitter and antennas. Queries should be
directed to the above address or by telephone to 0531/592 1212 or
0531/592 1210, or by telex to 952822 ptb d.

DCF77 Specifications

Location:      Mainflingen transmitter complex, (50:01N, 09:00E), about
               25km south-east of Frankfurt a. Main.

Carrier Frequency: Standard frequency 77.5kHZ, derived from the PTB
               atomic clocks. Relative deviation of the carrier from
               specifications:

               averaged over 1d:   <1e-12
               averaged over 100d: <2e-13

               The carrier phase is controlled so that deviations
               relative to UTC(PTB) are never greater than +-0.3us.
               Larger phase and frequency variation observed at the
               receiver are due to summation of ground and space waves.

Power output:  Transmitter power 50kw, estimated emitted power approx.
               25kW.

Antenna:       150m high (backup antenna 200m high) vertical
               omnidirectional antenna with top capacitance.

Transmission times: 24-hour continuous service. Short interruptions (of
               a few minutes) are possible if, because of technical
               problems or servicing,, the service must be switched to a
               backup transmitter or antenna. Thunderstorms can cause
               longer interruptions to the service.

Time signal:   The carrier is amplitude-modulated with second marks. At
               the beginning of each second (with the exception of the
               59th second of each minute), the carrier amplitude is
               reduced to 25% for the duration of either 0.1 or 0.2
               seconds. The start of the carrier reduction marks the
               precise beginning of the second. The minute is marked by
               the absence of the previous second mark.

               The second marks are phase-synchronous with the carrier.
               There is a relatively large uncertainty possible in the
               time of the second mark which depends on the receiver
               position. The causes are the relatively low bandwidth of
               the antenna, space wave and other interference sources.
               Despite this, it is possible to achieve accuracy better
               than 1ms at distances of several hundred kilometers.

Time code:     The transmission of the numerical values for minute,
               hour, day, weekday, month and year are BCD-encoded
               through the pulse duration modulation of the second
               marks. A second mark with duration 0.1s encodes a binary
               0 and a duration of 0.1s encodes 1. The order of encoding
               is shown in the following diagram [replaced by a table in
               this translation]. The three test bits P1, P2 and P3
               extend the 3 major sections of the time code (7 bits for
               minutes, 6 bits for the hour and 22 bits for the date,
               including the week day number) to maintain an even count
               of 1's.

               The second marks No. 17 and 18 indicate the time system
               for the transmitted time codes. In the case of
               transmission of MEZ, mark 18 has a duration of 0.2s and
               mark 17 a duration of 0.1s. If MESZ is being transmitted,
               this is reversed. Furthermore, an approaching transition
               from MEZ to MESZ or back is announced by extending mark
               16 from 0.1 to 0.2s for one hour prior to the changeover.

Encoding Scheme [diagram in original]

Mark number(s) Encodes (01.s=0, 0.2s=1)

0              Minute, always 0 (0.1s)
1-14           Reserved
15             0=Normal antenna, 1=backup antenna
16             1=Approaching change from MEZ to MESZ or back
17,18          Time zone 0,1=MEZ; 1,0=MESZ
19             The leap second is encoded in this bit one hour prior to
               occurrence.
20             Start bit for encoded time, always 1
21-27          1, 2, 4, 8, 10, 20, 40 Minutes (mark 21=1 minute)
28             P1 maintains even parity for marks 21-28
29-34          1,2,4,8,10,20 Hours (mark 29=1 hour)
35             P2 maintains even parity for marks 29-35
36-41          Day in month (1, 2, 4, 8, 10, 20)
42-44          Day in week (1,2,4)
45-49          Month number (1, 2, 4, 8, 10)
50-57          Year (1, 2, 4, 8, 10, 20, 40, 80)
58             P3 maintains even parity for marks 36-58 There is no mark
               transmitted for the 59th second.

Literature

P. Hetzel, "Die Zeitsignal- und Normalfrequenzaussendungen der PTB ueber
den Sender DCF77: Stand 1982" [The PTB time signal and standard
frequency transmissions from DCF77: Status 1982] in "Funkuhren" [Radio
clocks], W. Hilberg, Oldenburg Publishers, Munich & Vienna 1983, pp 42-
57.

G Becker & P. Hetzel, "Vortraege ueber DCF77" [Lectures: DCF77], PTB
Reports, PTB-Me-23 (1979), pp 185-253. Braunschweig 1984

Additional information: DCF77

Since July 1983, the DCF77 carrier has been phase modulated in a test
configuration. The phase modulation is a pseudorandom binary sequence
sent twice each second. The clock frequency of the binary sequence is
645.833...Hz and the phase shift \Delta\tau about 3% of the period
(\^{=} 10\deg). Equal numbers of shifts of +\Delta\tau and -\Delta\tau
are always sent, so that the mean frequency remains unchanged, and the
use of DCF77 as a frequency standard is unaffected. The timecode is
encoded in the sequence by inverting the sequence or not. Not inverted
sequence corresponds to a 0 bit. The sequence is alleged to be generated
by a 9 bit shift register which is coupled back on positions 5 and 9.
The polynomial might be:  x^9 + x^4 + 1.

Because the pseudo-random bitstring has a strictly deterministic nature,
the correlation analysis at the receiver end leads to a correlation
function with triangular form, and thereby to timing information. Early
test results show that the time information received with the help of
pseudo-random phase modulation is more resistant to interference and
more accurate (standard deviation \approx 10\mu s during the day and
\approx 25\mu s at night) than the conventional method using amplitude
modulated second marks. Since this new modulation method is compatible
with previous usage of DCF77, and that the users have made no
difficulties known to us, the tests have been extended. The transmission
of the pseudo-random phase distortion still has experimental status, and
should not be seen as a permanent commitment. Further information will
be made available in the future.

Announcement bit for a leap second
The DCF77 control unit is currently being modified so that in future an
announcement bit for a leap second can be sent. It is expected that for
the first time on 1st July 1985 the second mark Nr. 19 will be extended
to a length of 0.2s for one hour prior to the introduction of a leap
second. Intelligent receivers will then be able to recognise the
discontinuity and maintain correct indicated time in spite of a 61s
minute.

Availability

The clock was made by a local radio amateur.

Empfangsanlage DCF77 (SFr 690. complete, also available in kit form)

Walter Schmidt
Eichwisrain 14
8634 Hombrechtikon
Switzerland

LF reciever and decoder for the German time standard DCF77. As yet
untested. Has a 1s impulse output driven direct from the reciever, which
could be used in a similar manner to the pulse output on the Spectracom.
Internal crystal-controlled clock reset each minute by the DCF77 minute
mark. Indication available to program of whether currently synchronised,
and a count of how long since the last synchronisation is available if
running unsynchronised. Returns time with resolution 0.1s, but probably
synchronised to the time of command reception, and not to the 0.1s
counter. I will try to get the firmware changed if this is the case.

Last update: 91/06/05 - 13:34:36

Die folgende Liste ist einer Information der PTB entnommen.
Fuer evtl. Tippfehler wird nicht gehaftet (;-)
(Umlaute sind in ASCII Umschrift (ae,oe,ue,ss) dargestellt.)

Bei Erweiterungen/Aenderungen bitte email an time@informatik.uni-
erlangen.de

Other sources
                                                            Januar 1989
(PTB Original)

  Hersteller/Vetriebsfirmen von DCF77-Empfangsgeraeten
  ----------------------------------------------------

1. Funkuhren fuer Zeitdienst-Systeme (z. B. Funkuhren fuer Uhren-
   anlagen und Turmuhr-Zentralen; modulare Funkuhren mit RS 232-
   Schnittstelle fuer Rechner; funkgesteuerte Schaltuhren, Zeit-
   kodegeneratoren und Aussenuhren)


   Auerswald GmbH & Co. KG         Vor den Grashoefen 1
   Tel.: 05306/2021-2022           3302 Cremlingen,
                                   OT Schandelah

   Electronic Design Buero         Zeilstrasse 56
   Herwig Braun GmbH               7417 Pullingen
   Tel.: 07121/71560

   Ferrari electronic GmbH         Beusselstrasse 27
   Tel.: 030/3965021               1000 Berlin 21

   Gesellschaft fuer Datensysteme (GDS)  Hindenburgstrasse 13
   Tel.: 05306/7010                3302 Cremlingen
                                   OT Schandelah
                         
   Heliowatt Werke                 Wilmersdorfer Str. 39
   Elektrizitaets-Gesellschaft mbH 1000 Berlin 12
   Tel.: 030/31908-01

   Hopf Elektronik                 Postfach 18 47
   Tel.: 02351/45038               5880 Luedenscheid

   Philip Hoerz                    Moltkestrasse 6
   Turmuhren                       7900 Ulm
   Tel.: 0731/37168

 * Marcel Kreutler                 Postfach 37 44
   Zeit- und Informationstechnik   7500 Karlsruhe 1
   Tel.: 0721/85281

   Landis & Gyr GmbH               Friesstrasse 20 - 24
   Tel.: 069/40020                 6000 Frankfurt 60

   Lennartz Elektronic GmbH        Bismarkstrasse 136
   Tel.: 07071/3088                7400 Tuebingen

   Werner Meinberg Elektronik      Auf der Landwehr 22
   Tel.: 05281/2018                3280 Bad Pyrmont

   Aus dem Moore                   Postfach 21 41
   Turmuhr-Elektronik              4994 Preussisch
   Tel.: 05742/5225                Oldendorf 2

   Moser-Baer AG                   CH-3454 Sumiswald
   Tel.: 0041/34/721144            Schweiz

   Noelpp-Informationssysteme GmbH Friedensstrasse 41
   Tel.: 06101/87592               6368 Bad Vilbel 2

   Heinrich Perrot                 Postfach 13 51
   Turmuhrenfabrik                 7260 Calw-Heumaden
   Tel.: 07051/12055

 * Precitel SA                     Avenue du Mail 59
   Tel.: 0041/38/247555            CH-2000 Neuchatel
                                   Schweiz

   Georg Rauscher                  Wuerzburgstrasse 4
   Turmuhrenfabrik                 8400 Regensburg

 * Schwille-Elektronik             Benzstrasse 1
   Tel.: 089/9031041               8011 Kirchheim

   Siemens AG                      Postfach 53 29
   Tel.: 0511/1290                 3000 Hannover 1

   Telefunken electronic           Ringlerstrasse 17
   Tel.: 0841/8811                 8070 Ingolstadt

   Telenorma Uhren GmbH            Postfach 44 32
   Tel.: 069/266-1                 6000 Frankfurt 1

   ZERA Elektronische Pruefgraete  Postfach 11 60
   Cremer & Co.                    5330 Koenigswinter
   Tel.: 02223/22075

2. Funkuhren fuer den haeuslichen Gebrauch (z. B. Tisch- und Wand-
   uhren der Firmen Dugena, Hermle, Junghans, Kundo,...)
   Vertrieb durch den Uhrenfachhandel und die Fachabteilungen
   von Kauf- und Versandhaeusern
3. Funkuhr-Bausaetze und -Fertiggeraete
   Vertrieb durch den Elektronik-Fach- und Versandhandel

4. DCF77-Normalfrequenzempfaenger und Frequenzregler fuer Normal-
   frequenzoszillatoren

   Goerl HF-Messtechnik            Buchenstrasse 2
   Tel.: 0821/482613               8902 Neusaess 4

   Rohde & Schwarz                 Muehldorfstrasse 15
   Tel.: 089/4129-0                8000 Muenchen 80
         0911/86747 (Nuernberg)

   Unverdross Technik              Tutzinger Hof Platz 6
   Tel.: 08151/21198               8130 Starnberg

Die mit `*' gekennzeichneten Firmen unter 1. haben neben Funkuhren
auch DCF77-Normalfrequenzempfaenger in ihrem Vertriebsprogramm.

Diese Liste wurde erstellt aufgrund von Informationsmaterial, das
der PTB ueber DCF77-Empfangsgeraete vorliegt. Falls neue Produkte
auf den Markt kommen, eine Firma uebersehen wurde oder eine hier
aufgefuehrte Firma die Produktion von DCF77-Empfangsgeraeten einge-
stellt hat, bittet die PTB um Zusendung von entsprechenden Infor-
mationen, damit diese Zusammenstellung aktualisiert werden kann.

------------------------------------------------------------------------

            Time and Frequency Station MSF (United Kingdom)

Information entered by Philip Gladstone, extracted from a document
issued by Rugby (VLF) Radio Station.

Technical Details

Service             MSF 60 KHz

Radiated Power      16 KW

Schedule            24 hour (off for maintenance 1000-1400 GMT on the
first Tuesday of the month)

Duration of time
signal emission     Continuous

Time signal
modulation          A1 Negative 100mS at the second, 500mS at the minute

Epoch at            Carrier Fall

Carrier Frequency
Stability           +/- 3 in 10^12

Time Signal
Accuracy            0.1mS relative UTC

The Rubgy Frequency Standards

Three Hewlett Packard sources are used -- one type 5061A Caesium
Beam,and two type 5065A rubidium vapour -- and are installed in
acontrolled-environment cubicle together with an AUSTRON type 2055
microstepper. This last is a precision rate adjuster which is used to
vary the frequency of the Caesium standard to cater for the minute
differences (of order parts in 10^12) which exist between all Caesium
standards.
This results in a 5MHz output from a crystal oscillator which is part of
the feedback system. The 60KHz carrier is derived from this 5MHz by a
digital tripler consisting of three positive edge detectors on a delay
line using the propagation delay in integrated circuit inverters to
produce three pulses seperated by 66.6 nanoseconds in each 200nS cycle
of 5MHz. The resulting 15 MHz is then divided by 250 to obtain a square
wave at 60 KHz.

100 KHz outputs are used to drive the digital clocks -- three Venner TSA
5586 clocks which give parallel BCD time output. These clocks are set an
arbitrary 100 microseconds ahead of UTC (Rugby) to cater for the
unavoidable delays in drive generators and transmitters.

Time Stability

1.   UTC (Rugby) is compared with UTC (NPL) by measurements at both
     sites relative to a readily identifiable edge in the field sync
     pulse train of the BBC TV transmission from Sandy Heath

2.   UTC (NPL) is compared with UTC (BIH) by similar observations of a
     specified feature in the transmission from Sylt (7970-W) in the
     LORAN 'C' Norwegian Sea chain.

3.   Rugby then use results supplied by BIH and NPL to calculate a
     direct comparison between UTC at Rugby and BIH.

It should be noted that UTC (BIH) is a calculated 'paper' clock with no
physical existence of its own and actually derived from the average of
30 or so standard clocks throughout the world. UTC (Rugby) is currently
maintained within 4 parts in 10^13 of agreement with UTC (BIH), a
comfortable margin over the claimed stability of 3 in 10^12.

Why called MSF?

It is a callsign like 2LO and GBR and while SF was the obvious acronym
for Standard Frequency a three letter callsign could only begin with 2,
G or M, the prefixes allocated to the UK by international agreement for
station identification. M was available for use with the letters SF, G
was not, so there was really very little choice in the matter.

Pulse Train

The Minute epoch is marked by a 500 mS break in the carrier. Actually,
there is data transmitted in this gap, but very few people use it. There
are four other types of signal that can be sent on the second.

______       _______________
      |     |
      |     |                           Zero (normal marker)
      |_____|

______            _______________
      |          |
      |          |                      One (Time, date, identifier)
      |__________|

______                 _______________
      |               |
      |               |                 Identifier one plus Parity or
      |_______________|                     BST one

______       ____      _______________
      |     |    |    |
      |     |    |    |                 DUT1 one
      |_____|    |____|
      ^     ^    ^    ^
      |     |    |    300 ms
      |     |    200 ms
      |     100 ms
      0 (Second Epoch)

Second

0         500ms break (100 Hz code)
1-8       Positive DUT1 (use either Zero or DUT1)
9-16      Negative DUT1 (use either Zero or DUT1)
17-24     Year (80,40,20,10,8,4,2,1) (Use Zero or One)
25-29     Month (10,8,4,2,1) (Use Zero or One)
30-35     Day (20,10,8,4,2,1) (Use Zero or One)
36-38     Day of Week (4,2,1) (Use Zero or One)
39-44     Hour (20,10,8,4,2,1) (Use Zero or One) (Localtime)
45-51     Minute (40,20,10,8,4,2,1) (Use Zero or One)
52        Zero
53        BST/UTC Change next hour (Use One or Ident)
54        Parity (over 17-24) (Use One or Ident)
55        Parity (over 25-35) (Use One or Ident)
56        Parity (over 36-38) (Use One or Ident)
57        Parity (over 39-51) (Use One or Ident)
58        BST (Use One or Ident)
59        Zero

Notes

1.   The 1Hz data applies to the following minute

2.   When BST is in force, bit 58 is 300 mS and Data is 61 minutes fast
     of UTC. Bit 53 is 300 mS for the hour preceeding (0100 UTC) changes
     to and from BST.

3.   Day 0 is Sunday

4.   Parity sense is Odd.

5.   The first 'n' bits in the DUT1 code being DUT1 (rather than Zero)
     indicates 0.'n' positive or negative DUT1.

DUT1 is set up on switches to instructions via the Royal Greenwich
Observatory, changes occurring approximately every five weeks.

GMT is Greenwich Mean Time -- this is really UTC
BST is British Summer Timer which is one hour ahead of GMT.

Details of this can be obtained from

Division of Electrical Science
National Physical Laboratory
Queens Road
Teddington
Middlesex TW11 0LW
United Kingdom

Decoding Clocks

A number of clocks are available in the UK, ranging from wall clocks at
around 100 UKP to digital computer clocks at 1000-2000 UKP. Hobbyist
kits are also available at around 20 UKP that provide the raw 1 Hz data.

------------------------------------------------------------------------

            Time and Standard Frequency Station TDF (France)
Provided courtesy of Richard B. Langley, University of New Brunswick

Station:       TDF, Allouis, France

Address:       Centre National d'Etudes des Telecommunications
               PAB - STC - Etalons de frequence et de temps
               196 avenue Henri Ravera
               F - 92220  Bagneux
               France

Coordinates:   47d 10' N, 2d 12' E

Frequency:     162 kHz

Power:         2,000 kW

Schedule:      continuous except every Tuesday from 01:00 to 05:00 UTC

Form of Time Signals:

TDF is an amplitude modulated longwave broadcasting station,
transmitting the programs of the France-Inter Network of Telediffusion
de France (TDF). Time signals are transmitted by phase modulation of the
carrier by + and -1 radian in 0.1 s every second except the 59th second
of each minute. This modulation is doubled to indicate binary 1.  The
numbers of the minute, hour, day of the month, day of the week, month
and year are transmitted each minute from the 21st to the 58th second,
in accordance with the French legal time scale.  In addition, a binary 1
at the 17th second indicates that the local time is 2 hours ahead of UTC
(i.e., summer time), a binary 1 at the 18th second indicates when the
local time is 1 hour ahead of UTC (i.e., winter time).  A binary 1 at
the 14th second indicates that the current day is a public holiday (14
July, Christmas, etc.) and a binary 1 at the 13th second indicates that
the current day is the day before a public holiday.

Relative Uncertainty of the Carrier Frequency:  2 parts in 10^12.

Radio Clocks Available:

Horloge 59 HF
  BHL Electronique
  Zone Industrielle
  B.P. 8
  F - 14540  Bourguebus
  France

Recepteur horaire sur France-Inter G-O
  Dyna Electronique
  36 avenue Gambetta
  F - 75980  Paris Cedex 20
  France

RTD 101
  telematique SA
  Zirst-chemin des pres
  F - 38240  Meylan
  France

Information Sources:

Annual Report of the BIPM Time Section for 1989, Bureau International
des Poids et Mesures, Pavillon de Breteuil, F - 92312 Sevres Cedex,
France.
Zeitzeichensender / Time Signal Stations (bilingual: German and English)
by Gerd Klawitter, Siebel Verlag, Bonhoeffer Weg 16, D-5309  Meckenheim,
Germany.

The phase modulation pattern.
-----------------------------

One signal element consists of the following : the phase of the carrier
is advanced linearly up to +1 radian in 0.025 second, then retarded
linearly up to -1 rad in 0.050 second, then advanced again to reach zero
after another 0.025 second. One signal element is always sent at each
second between 0 and 58. The epoch is when the down ramp crosses zero.
If a '1' bit is to be stransmitted, two signal elements are sent in
sequence. Since the phase is the integral of the frequency, to this
triangular phase modulation corresponds a square frequency modulation
with an amplitude of about + and - 6Hz.

                 binary '0'                      binary '1'


                 / \                       / \         / \
  phase     ___ /   \       ___       ___ /   \       /   \       ___
                      \   /                     \   /       \   /
                       \ /                       \ /         \ /

   (0.025 s    |  |  |  |  |             |  |  |  |  |  |  |  |  |
    ticks)           |                         |
                   epoch                     epoch

                __       __               __       _____       __
               |  |     |  |             |  |     |     |     |  |
 frequency  ___|  |     |  |___       ___|  |     |     |     |  |___
                  |     |                   |     |     |     |
                  |_____|                   |_____|     |_____|

Both the average phase and the average frequency deviation are thus
zero. More data is sent by phase modulation during the rest of each
second. But the second marker (and data bit) is always preceded by 0.1
second without modulation. There is no marker at the beginning of the
59th second, nor any data sent during the entire duration of that
second.

The binary encoding of date and time data.
------------------------------------------

Seconds 20 to 58 carry exactly the same information as the signal of the
German transmitter DCF77.

*-----------------------------------------------------------------------

               * Time and Frequency Station CHU (Canada)

Information provided by Nick Sayer (mrapple@quack.sac.ca.us)

CHU is a radio station in Canada that broadcasts time of day information
sort of like WWV. CHU transmits on 3330 kHz, 7335 kHz, and 14670 kHz
using AM compatable single-sideband full carrier modulation. Between 31
and 39 seconds (inclusive) past the minute, CHU transmits a computer
readable timecode. This timecode includes time of day UTC, day of year
(1-366), Gregorian year, leap second warning, DUT (the difference
between UTC and UT1, which is an astronomical timescale. The difference
is an integral number of tenths of a second between -.9 and +.9. If the
difference exceeds .7, they schedule a leap second), and a Canadian
daylight time indicator.
The datastream is in the form of an AFSK datastream. The frequencies are
compatable with the Bell 103 standard: 2225 Hz mark and 2025 Hz space.
The carrier is active between 10 and 510 msec past the second. Each byte
of data is encoded as one start bit, 8 data bits and two stop bits.
There are ten bytes in each packet, and the last stop bit ends at
precisely 500 msec past the second. ( 1 start bit + 8 data bits + 2 stop
bits ) * 10 characters = 110 bits. Each bit takes 1/300 of a second (300
baud). So the whole code takes 366.66.. msec. 500-366.66... = 133.33...
msec. So graphically, each second looks like this:

000   050   100   150   200   250   300   350   400   450   500   550
|  |            |                                           |  |
  ^       ^                        ^                         ^   ^
  1       2                        3                         4   5

1 - Ticking noise.
2 - 2225 Hz mark tone for 123.333 msec to allow modems to set up
3 - Data stream
4 - 2225 Hz mark tone for 10 msec to avoid false overrun of the stop
bits
5 - silence until the end of the second.

The datastream itself consists of ten bytes. There are two possible
formats at the moment: One for second 31 and the other for seconds 32
through 39. Each format has 5 bytes of data, then 5 bytes of redundancy.
The "A" format redundancy bytes are exactly the same as the data bytes.
The "B" format redundancy bytes are exactly inverted (one's complement,
NOT, XOR 0xff, etc) from the data bytes. This is how one can tell what
sort of frame was received.

Once the data is received and the redundancy bytes are checked, the next
thing to do is to swap the least and most significant nibbles in each
byte. After doing all of this, the frames look like this:

A frame:     6d dd hh mm ss

ddd is the day of the year. hh:mm:ss is the time UTC. 6 is a constant.
Each nibble is a BCD digit.

B frame:     xd yy yy tt ab

d is the absolute value of DUT in tenths of a second. yyyy is the
gregorian year, tt is the difference between TAI and UTC, a is a flag
indicating canadian daylight time (contents of this nibble are
undocumented at the moment), b is a serial number (this nibble
increments whenever the B frame is changed), and x is a bitwise field:

   8  4  2  1
   |  |  |  |
   |  |  |  +--- The sign of DUT (0=+).
   |  |  +------ Leap second warning. One second will be added.
   |  +--------- Leap second warning. One second will be subtracted.
   +------------ Even parity bit for this nibble.

A sample A frame as received from the modem might look like this:

36 56 21 51 53 36 56 21 51 53

Note that these numbers are in hex. This translates to the 365th day of
the year (Dec 31, or Dec 30 in a leap year), 12:15:35 UTC.

A sample B frame as received from the modem might look like this:

19 91 39 72 00 e6 6e c6 8d ff
This translates to a DUT of -.1, year 1993, TAI-UTC=27, serial number 0
and no canadian daylight time.