Meinberg M900 User manual

Technical Information
Operating Instructions
M900
GPS/PZF
Redundant/SHS

Contact Information
Meinberg Funkuhren GmbH & Co. KG
Lange and 9
D-31812 Bad Pyrmont
Telephone: [phone] / 9309-0
Telefax: +49 (0) 52 81 / 9309-30
Internet: http://www.mein erg.de
E-Mail: info@mein erg.de
Bad Pyrmont, 4. September 2009

Ta le of Contents
Quick Start..................................................................................................................... 9
Network Timeserver with redundant time base........................................................... 11
Redundant Mode..................................................................................................11
SHS Mode............................................................................................................12
The Modular System LANTIME.................................................................................13
Supported Network Services................................................................................14
Additional Features and Options......................................................................... 15
User Interface.......................................................................................................15
Options.................................................................................................................15
hy to use a Network Timeserver...................................................................... 16
Network Time Protocol (NTP).................................................................................... 16
NTP Target...........................................................................................................17
GPS satellite controlled clock......................................................................................17
GPS170 Features..................................................................................................19
Time Zone and Daylight Saving.......................................................................... 19
Mounting the GPS Antenna.........................................................................................20
Assembly with CN-UB/E.................................................................................... 21
General information DCF77 PZF................................................................................ 22
Features of PZF5xx..................................................................................................23
Antenna........................................................................................................................24
Assembly of antenna............................................................................................24
Precision Time Protocol (PTP) / IEEE1588v2............................................................ 25
General Information.............................................................................................26
Functionality in Master Systems..........................................................................27
Functionality in Slave Systems............................................................................27
Booting the GPS receiver.............................................................................................28
Booting the PZF receiver.............................................................................................28
Booting the Single Board Computer............................................................................29
Configuration User Interface....................................................................................... 30
The menus in Detail................................................................................................. 31

Root Menu........................................................................................................... 31
Menu: Reference Time.............................................................................................33
Menu: Info GPS................................................................................................... 33
GPS Status & Version..........................................................................................34
GPS Receiver Position.........................................................................................34
GPS Satellite Constellation..................................................................................35
Menu: Setup GPS.................................................................................................35
Set Antenna Cable Length................................................................................... 35
Set GPS Receiver Simulation Mode.................................................................... 36
Menu: Init GPS.................................................................................................... 36
Initiate Cold Boot of GPS Receiver.....................................................................36
Initiate arm Boot of GPS Receiver...................................................................37
Init Receiver Position...........................................................................................37
Init Receiver Time............................................................................................... 37
Menu: Setup GPS Outputs................................................................................... 38
Enable Outputs.....................................................................................................38
Setup Serial Outputs............................................................................................ 39
Setup Time Zone..................................................................................................40
Menu TIME CODE IRIG (Output)......................................................................41
Menu Synthesizer Frequency Output...................................................................41
Programmable pulse (Option)..................................................................................42
SETUP POUT X.................................................................................................. 42
Mode.................................................................................................................... 42
Timer mode..........................................................................................................43
Single Pulse..........................................................................................................43
Cyclic mode......................................................................................................... 44
PPS, PPM, PPH Modes........................................................................................44
Menu: PZF Reference Time.....................................................................................45
Info PZF............................................................................................................... 45
Status & Version.................................................................................................. 45
Correlation & Field.............................................................................................. 45
Setup PZF.............................................................................................................46
Transmitter Distance............................................................................................46
Ignore Lock (Simulation Mode).......................................................................... 47
Initial Time...........................................................................................................47
Setup Serial Out................................................................................................... 47
Menu: Time Service.................................................................................................48
Menu: external NTP server..................................................................................48
Menu: Stratum of local clock...............................................................................49
Menu: Reset Time................................................................................................49
Menü: 2nd Receiver.............................................................................................50
Menu: PTP IEEE 1588.........................................................................................51
Menu: PTP V1......................................................................................................... 51
Menu: PTP V2......................................................................................................... 52
Menu: Network........................................................................................................ 54
Menu: Global Configuration................................................................................55
Menu: Network Interfaces................................................................................... 56

Menu: Setup IPv4 Parameter............................................................................... 56
Menu: Setup IPv6 Parameter............................................................................... 57
Menu Link Mode................................................................................................. 57
Menu: Network Services......................................................................................58
Menu: System...................................................................................................... 58
Menu: Time Zone................................................................................................ 58
The LANTIME configuration interfaces..................................................................... 60
The EB interface...................................................................................................... 61
Configuration: Main Menu...................................................................................... 62
Configuration: Ethernet........................................................................................... 63
Network interface specific configuration.................................................................65
IPv4 addresses and DHCP................................................................................... 65
IPv6 addresses and autoconf................................................................................ 65
High Availability Bonding...................................................................................66
Additional Network Configuration...................................................................... 67
Configuration: Notification......................................................................................68
Alarm events........................................................................................................ 69
E-mail messages...................................................................................................69
indows Popup Messages.................................................................................. 70
SNMP-TRAP messages....................................................................................... 70
VP100/NET wall mount display..........................................................................70
User defined Alarm scripts.................................................................................. 71
NTP Client Monitoring........................................................................................ 71
Alarm messages................................................................................................... 72
Configuration: Security............................................................................................73
Password.............................................................................................................. 74
HTTP Access Control.......................................................................................... 74
SSH Secure Shell Login.......................................................................................75
Generate SSL Certificate for HTTPS ..................................................................76
NTP keys and certificates.................................................................................... 77
SNMP Parameter................................................................................................. 77
Configuration: NTP................................................................................................. 78
NTP Authentication............................................................................................. 81
NTP AUTOKEY..................................................................................................83
Configuration: Local................................................................................................86
Administrative functions......................................................................................87
User Management................................................................................................ 88
Administrative Information................................................................................. 89
Software Update...................................................................................................91
Automatic configuration check............................................................................92
Get Diagnostics Information................................................................................93
eb interface language........................................................................................93
Configuration: Statistics.......................................................................................... 94

Statistical Information..........................................................................................95
Configuration: Manual.............................................................................................96
The Command Line Interface...................................................................................... 98
CLI Ethernet.............................................................................................................99
CLI Notification.....................................................................................................102
Alarm events...................................................................................................... 102
E-mail messages.................................................................................................103
indows Popup Messages................................................................................ 103
SNMP-TRAP messages..................................................................................... 104
VP100/NET wall mount display........................................................................104
NTP Client Monitoring...................................................................................... 105
CLI Security...........................................................................................................106
Password............................................................................................................ 106
SSH Secure Shell Login.....................................................................................106
Generate SSL Certificate for HTTPS ................................................................107
NTP keys and certificates.................................................................................. 107
CLI NTP Parameter............................................................................................... 108
CLI NTP Authentication....................................................................................109
CLI NTP Autokey..............................................................................................109
CLI Local............................................................................................................... 110
Administrative functions....................................................................................110
User Management.............................................................................................. 111
Administrative information................................................................................111
Software Update.................................................................................................113
SNMP Support...........................................................................................................114
Configuration over SNMP .................................................................................... 116
Examples for the usage of the SNMP configuration features............................117
Further configuration possibilities..................................................................... 118
Send special timeserver commands with SNMP............................................... 118
Configuration of the timeserver with SNMP: Reference...................................120
SNMP Traps...........................................................................................................123
SNMP Trap Reference....................................................................................... 124
Attachment: Technical Information...........................................................................125
Skilled/Service-Personnel only: Replacing the Lithium Battery...........................125
Technical Specifications LANTIME BGT............................................................ 125
Safety instructions for building-in equipment....................................................... 126
CE-Label................................................................................................................ 126

Front- / Rear Panel Connectors..............................................................................127
Connector Assignments..................................................................................... 128
RS232 TERMINAL........................................................................................... 128
Time Sync Error Relay.......................................................................................... 129
Technical Specification......................................................................................129
Technical Specifications GPS receiver..................................................................130
Oscillator options............................................................................................... 131
Technical Specifications GPS Antenna............................................................. 132
Signal Description GPS170............................................................................... 133
Rear Connector Pin Assignments GPS170........................................................ 134
Technical specifications PZF5xx...........................................................................135
Signal description PZF5xx.................................................................................137
Rear Connector Pin Assignments PZF5xx........................................................ 138
Technical Specifications LAN CPU...................................................................... 139
Rear Connector Pin Assignments LAN CPU.................................................... 140
VGA, Keyboard Connector Pin Assignments....................................................140
Technical Specifications Power Supply Unit PULS AP 336-505......................... 141
Front Panel and Rear Connector Pin Assignments............................................ 141
Timecode (option)..................................................................................................142
Abstract.............................................................................................................. 142
Principle of Operation........................................................................................142
Block Diagram Timecode.................................................................................. 142
IRIG Standard Format........................................................................................143
AFNOR Standard Format.................................................................................. 144
Assignment of CF Segment in IEEE1344 Code................................................ 145
Generated Time Codes.......................................................................................146
Selection of Generated Time Code.................................................................... 146
Outputs...............................................................................................................147
AM - Sine ave Output.................................................................................... 147
P M DC Output............................................................................................... 147
Technical Data................................................................................................... 147
Time Strings...........................................................................................................148
Format of the Meinberg Standard Time String..................................................148
Format of the GPS Capture String..................................................................... 149
Format of the SAT-Time String.........................................................................150
Format of the Uni Erlangen String (NTP) ........................................................ 151
Format of the NMEA 0183 String (RMC).........................................................153
Format of the ABB SPA Time String................................................................ 154
Format of the COMPUTIME Time String.........................................................155
Format of the RACAL standard Time String.................................................... 156
Format of the SYSPLEX-1 Time String............................................................157
Konformitätserklärung...........................................................................................158
Manual VP100/NET Display configuration.......................................................... 159
Global Configuration File...................................................................................... 161

Global Option File................................................................................................. 162
Third party software...............................................................................................163
Operating System GNU/Linux.......................................................................... 163
Samba.................................................................................................................163
Network Time Protocol Version 4 (NTP)..........................................................164
mini_httpd.......................................................................................................... 164
GNU General Public License (GPL)................................................................. 165
Reference............................................................................................................... 169

Quick Start
hen booting the system the following message will be displayed while dots will
be counted up in the lower line:.
Starting up
Please wait. . .
. . . .
Main Menu will be displayed with some important status informations after booting
has finished:
GPS:SYN PZF:SYN
NTP:SYN SHS:0ms
Thu, 01.01.2008
TC 12:00:00
If the GPS receiver remains asynchronous (Ref.Time LED is still red after 12
minutes) the number of satellites in view and the good satellites are to check (press
buttons i,OK,OK,OK,i,i,OK from main menu). The antenna has to be installed
without any obstructions to the sky.
SV CONSTELLATION
SV in view: 10
Good Svs : 9
Sel:01 21 16 22
If the PZF receiver remains asynchronous the field strength has to be checked (press
buttons i,OK,i,OK,OK,i,OK from main menu). The antenna has to be installed at a
proper position.
PZF STATE
CORR.: 66
STATE: fine
FIELD: 95
M300 can be used in redundant mode or in SHS (Secure Hybrid System) mode. In
redundant mode the internal NTPD will choose one of the both reference clocks
depend on the reachability and jitter. In SHS mode the difference between GPS and
PZF will be calculated and if the limit will be reached the internal NTPD will be
stopped.
ith the buttons i,i,OK,i,OK from main menu „Fall Back Mode“ can be set to
SHS or Redundant mode.
9

->FallbackMode<-
Timelimits
For first time installation enter TCP/IP address, netmask and default gateway. To get
an overview of the current configuration press F2 from main menu. Press F2 again to
enter SETUP configuration page. Please ask your administrator for propper TCP/IP
configuration:
Global Cfg.
->Interfaces <-
Services
Choose the menu point “Interfaces” to change to IPV4 ETH0 configuration page to
enter the IP address, netmask and the default gateway:
NOTE: These settings are related to the first Ethernet connection (ETH0).
SET P
Ipv4 ETH0
DHCP: disabled
172.16.3.226
SET P
IPv4 ETHO
Ipv4 NETMASK:
255.255.255.0
SET P
IPv4
Ipv4 GATEWAY:
172.16.3.1
After this all further settings can be done via network interface, either by using a
EB browser or a Telnet Session.
Default user: root
Default password: timeserver
10

Network Timeserver with redundant time ase
LANTIME (Local Area Network Timeserver) provides a high precision time base
to a TCP/IP network (Stratum-1-Server). The NTP (Network Time Protocol) is used
to synchronize all NTP clients with the reference. The several LANTIME variants
differ from each other by the time reference. A GPS receiver, a DCF77 receiver or an
IRIG time code receiver can be integrated as an internal reference as well as a
combination of these references (hybrid system). External references are also
possible. The LANTIME/M900-GPS-PZF is a set of equipment composed of a
satellite controlled clock GPS170, a PZF receiver, a single-board computer with
integrated network board and a power supply, all installed in a metal 19" modular
chassis and ready to operate. A simplified LINUX operating system is installed on the
single-board computers flash disk. Both reference clocks the GPS and the PZF
receiver will be managed as redundant clocks by the NTP directly. Eight push buttons
and a 4 x 40 character LC display can be used to configure and monitor the
timeserver. After the network connection has been established the timeserver can also
be configured and monitored remotely from a workstation via TELNET or FTP. An
integrated HTTP server enables access to the LANTIME by using an ordinary EB
browser.
Redundant Mode
In redundant mode the internal NTPD will choose one of the both reference clocks
depend on the reachability and jitter. Both reference clocks are connected with serial
line and PPS to the internal NTPD. In main menu in the second line the current
chosen reference will be shown.
GPS:SYN PZF:SYN
NTP:SYN REF:GPS
Thu, 01.01.2008
TC 12:00:00
11

SHS Mode
GPS:SYN PZF:SYN
NTP:SYN SHS:0ms
Thu, 01.01.2008
TC 12:00:00
Secure Hy rid System with Strongly Verificated Reference Time
Mein erg LANTIME devices are Stratum-1 time servers which provide a high-
accuracy reference time to TCP/IP networks via the Network Time Protocol (NTP).
The main difference between the LANTIME models is the primary time source from
which a device derives its reference time. Primary time source options include
external radio clocks, built-in DCF77, GPS, or IRIG receivers, and even a hybrid
combination of a DCF77 and a GPS receiver.
The M300/SHS (Secure Hybrid System) has a built-in hybrid radio clock which
derives its reference time from both the satellite based Global Positioning System
(GPS) and long wave receiver PZF5xx. During normal operation the hybrid radio
clock passes the highly accurate reference time on to the built-in NTP time server
which makes the reference time available to the network.
In order to prevent the NTP server from spreading a faulty reference time in the
network, the hybrid receiver includes two independent standard radio clocks. Both the
satellite receiver GPS170 and the long wave receiver PZF5xx have their own signals
and high quality crystal oscillators which let the radio clocks provide accurate time
even if their primary time transmitters cannot be received for a few days.
The two radio clocks derive their time telegrams and high accuracy pulse-per-second
(PPS) signals from two independent primary time sources. The time telegrams and the
PPS signals output by the clocks are compared against each other. If either the
difference between the time telegrams or the difference between the PPS signals
exceeds a configurable limit of some milliseconds the internal NTPD will be stopped.
If it is necessary to provide redundancy against hardware failure then it is also
possible to install several LANTIME NTP servers in the same network.
12

The Modular System LANTIME
LANTIME is a set of equipment composed of a satellite controlled clock GPS170,
a DCF77 long wave receiver, a single-board computer SBC LX800 500 MHz with
integrated network card, and a power supply unit, all installed in a metal desktop case
and ready to operate. The interfaces provided by LANTIME are accessible via
connectors in the rear panel of the case. Details of the components are described
below.
The implemented NTPD distributes the reference time from the GPS receiver cyclic
in the network. Information on the NTPD is monitored on the LC display or can be
inquired via the network.
13
Terminal connector
serial interface
Vt100, 38400Baud,8N1
Nullmodem
to PC
Status LED eferenz time: green: synchronized red: error
Status LED NTP time service: green: synchronized red: error
Status LED Network connection: green: Link red: error
Status LED Alarm: red: error
OK button: save changes
or enter submenu
ESC button: cancel menu
and one level up
4 arrow buttons: select next
menu and change value of
parameters
LC - Display 4 x 16 chars
USB connector
for USB Stick
ETH4
Network
connectors
j45 10/100 Mbit
F1 button: show help
and additional informations F2 button: overview
of network parameters
Error elais
output
Output:
10MHz, PPS
TC DCLS (option)
TC_mod. (option)
Mounting wholes
for 19” cabinet
Antenna
Power supply
S232 output
serial interface
Input:
PPSin
TC DCLS (option)
TC_mod. (option)

The installation of LANTIME is very easy for the system/network administrator. The
network address, the netmask and the default gateway have to be configured from the
front panel of LANTIME. The network address or the equivalent name of LANTIME
has to be shown to all NTP clients in the TCP/IP network.
As well as NTP the Linux system also supports a number of further network
protocols: HTTP(S), FTP, SSH and Telnet. Because of this remote configuration or
status requests can come from any EB browser. This access via the network can be
deactivated. Changes in the receiver status, errors or other important events are
logged either on the local Linux system or on an external SYSLOG-Server. In
addition messages can be sent to a data center via SNMP traps or automatically
generated e-mails where they can be recorded. Furthermore all alarm messages can be
displayed by the large display VP100/20/NET that is accessed via network
connection. In order to avoid a service interruption several LANTIME NTP servers
can be installed in the same network to obtain redundancy.
Supported Network Services
The following network services are provided via RJ45 10/100Base-T Ethernet (Auto
sensing):
- NTP v2, v3, v4
- NTP broadcast mode
- NTP multicast
- NTP symmetric keys
- NTP Autokey
- Simple Network Time Protocol (SNTP)
- TIME
- SNMP v1,2,3 with extended SNMP-Agent and SNMP-Traps for NTP and
reference clock status
- DHCP Client
- NFS
- TELNET
- FTP
- HTTP
- HTTPS with Openssl2
- SSH2 Secure Shell Login
- Alarm messages via e-mail
- IPv6
- 3 global IPv6 addresses configurable
- Autoconf Feature to be disabled
- supported network services: NTP, HTTP, HTTPS, SNMP, SSH
- indows „net time“ via NETBIOS
- inpopup ( indow Mail)
14

Additional Features and Options
- external NTP timeserver
- free configuration of NTP: thereby MD5 authentication and access control via
address & mask restriction
- extended menu guidance for configuration and monitoring via Telnet, SSH or
serial terminal interface
- optional up to 3 RJ45/10/100 Mbit Ethernet interfaces
- extended HTTP statistic support with long-term graphic and access statistic to
NTP
- alarm messages can be displayed on external large display VP100/20/NET
- USB memory stick slot for extended functionality: software update, transfer of
secure certificates, log files and configurations, keypad locking
User Interface
- terminal connection via serial interface, status LED
- eb browser interface with graphical statistic of the one-day cycle offsets
- Telnet or Secure Shell Login for password protected operation of the Linux
operating system
- FTP access for updating the operating system and downloading log files
- Simple Network Management Protocol for automatically SNMP-Traps in case of
alarm
- SYSLOG messages can be passed to different computers
- configurable e-mail notification
- Simulation of a synchronous radio clock in order to operate without antenna
Options
- up to two further Ethernet RJ45 connectors
- Frequency and pulse outputs via BNC connectors (e.g. 10 MHz, 2.048 MHz, PPS)
- higher free running accuracy with optional oscillators (OCXO)
- IRIG-B outputs
- ANZ14/NET or VP100/20/NET as display connected via network
15

Why to use a Network Timeserver
A network timeserver should be used if accurate time is essential for undisturbed
operation. It is possible to synchronize computers in a network using Public Domain
Time servers over the Internet, but there are good reasons not to use them:
- The possibility to send notification via e-mail or SNMP-Trap to an administrator
in the event of any synchronisation failure.
- The computers in the network do not have a reliable internet connection.
- The computers in the network cannot rely on the availability of external
timeservers. Most operators of these timeservers do not guarantee continuous
availability nor the accuracy of their service.
- NTP is able to compensate for the propagation delay of the network packets only
in case of “usual” internet traffic. However, if unforeseen occurrences cause
badly fluctuating propagation times, it is possible that the time synchronisation
is disturbed. Reasons for this may be: hacker attacks, numerous upcoming new
viruses etc.
- An own timeserver cannot be easily compromised by external sources.
Network Time Protocol (NTP)
NTP is a common method for synchronization of hardware clocks in local and
global networks. The basic concept, version 1 [Mills88], was published in 1988 as
RFC (Request For Comments). Experiences made from the practical use in Internet
was followed by version 2 [Mills89]. The software package NTP is an
implementation of the actual version 3 [Mills90], based on the specification RFC-
1305 from1990 (directory doc/NOTES). Permission to use, copy, modify and
distribute this software for any purpose and without fee is hereby granted (read File
COPYRIGHT).
NTP's way of operation is basically different from that of most other protocols. NTP
does not synchronize all connected clocks, it forms a hierarchy of timeservers and
clients. A level in this hierarchy is called a stratum, and Stratum-1 is the highest level.
Timeservers of this level synchronize themselves by a reference time source, such as
a radio controlled clock, GPS-receiver or modem time distribution. Stratum-1-Servers
distribute their time to several clients in the network which are called Stratum-2.
A high precision synchronization is feasible because of the several time references.
Every computer synchronizes itself by up to three valued time sources. NTP enables
the comparison of the hardware times and the adjustment of the own clock. A time
precision of 128 ms, often better than 50 ms, is possible.
16

NTP Target
The software package NTP was tested on different UNIX systems. Many UNIX
systems have pre-installed a NTP client. Only some configurations have to be made
(/etc/ntp.conf). NTP clients as freeware or shareware are also available for the most
other operating systems like indows XP/2000/NT/95/98/3x, OS2 or MAC. The
following EB site is recommended to get the latest version of NTP:
"http://www.eecis.udel.edu/~ntp/". More information you can find on our web page at
"http://www.meinberg.de/english/sw/ntp.htm".
GPS satellite controlled clock
A Meinberg GPS170 satellite controlled radio clock is used as a reference time
base. The satellite receiver clock GPS170 has been designed to provide extremely
precise time to its user. The clock has been developed for applications where
conventional radio controlled clocks can not meet the growing requirements in
precision. High precision available 24 hours a day around the whole world is the main
feature of the new system which receives its information from the satellites of the
Global Positioning System.
The Global Positioning System (GPS) is a satellite-based radio-positioning,
navigation, and time-transfer system. It was installed by the United States Department
of Defence and provides two levels of accuracy: The Standard Positioning Service
(SPS) and the Precise Positioning Service (PPS). hile PPS is encrypted and only
available for authorized (military) users, SPS has been made available to the general
public.
GPS is based on accurately measuring the propagation time of signals transmitted
from satellites to the user’s receiver. A nominal constellation of 21 satellites together
with 3 active spares in six orbital planes 20000 km over ground provides a minimum
of four satellites to be in view 24 hours a day at every point of the globe. Four
satellites need to be received simultaneously if both receiver position (x, y, z) and
receiver clock offset from GPS system time must be computed. All the satellites are
monitored by control stations which determine the exact orbit parameters as well as
the clock offset of the satellites' on-board atomic clocks. These parameters are
uploaded to the satellites and become part of a navigation message which is
retransmitted by the satellites in order to pass that information to the user’s receiver.
17

The high precision orbit parameters of a satellite are called ephemeris parameters
whereas a reduced precision subset of the ephemeris parameters is called a satellite’s
almanac. hile ephemeris parameters must be evaluated to compute the receiver’s
position and clock offset, almanac parameters are used to check which satellites are in
view from a given receiver position at a given time. Each satellite transmits its own
set of ephemeris parameters and almanac parameters of all existing satellites.
18

GPS170 Features
The integrated GPS170 satellite receiver is connected to the antenna/converter unit
by a 50 Ω coaxial cable (refer to "Mounting the Antenna"). Feeding the
antenna/converter occurs DC insulated via the antenna cable. Optionally an antenna
splitter for up to four receivers connected to one antenna is available.
The navigation messages sent by the GPS satellites are decoded by the GPS170´s
microprocessor in order to track the GPS system time with an accuracy of better than
250 ns or 100 ns (depending on the oscillator type of the unit). Compensation of the
RF signal’s propagation delay is done by automatic determination of the receiver’s
geographical position. A correction value computed from the satellites´ navigation
messages increases the accuracy of the board’s TCXO or OCXO to 10-9 and
automatically compensates the aging effect. The correction value is stored in a battery
buffered memory and speeds up initial synchronization at power-up.
Time Zone and Daylight Saving
The GPS time differs from the universal time scale (UTC) by the number of leap
seconds which have been inserted into the UTC time scale after GPS started in 1980.
The current number of leap seconds is part of the navigation message supplied by the
satellites, so the GPS170 receivers internal time scale is based on UTC. Conversion to
local time including handling of daylight saving year by year can be done by the
receiver’s microprocessor if the corresponding parameters are configured.
The LANTIME NTP service always runs on UTC time as it is defined in the NTP
standard RFCs. LANTIME models with an LC display are capable of using local
time for the on-display clock. On these models the required time zone settings (UTC
offset, daylight savings time dates) can be set up using the front panel menu. The
local timezone settings can also apply to certain time output signals (e.g. Serial time
strings) if they support to output local time instead of UTC. The availability of these
outputs depends on the LANTIME model and optional modules/connectors.
19

Mounting the GPS Antenna
The GPS satellites are not stationary but circle round the globe in a period of about
12 hours. They can only be received if no building is in the line-of-sight from the
antenna to the satellite, so the antenna/converter unit must be installed in a location
from which as much of the sky as possible can be seen. The best reception is given
when the antenna has a free view of 8° angular elevation above the horizon. If this is
not possible the antenna should be installed with a mostly free view to the equator
because of the satellite courses which are located between latitudes of 55° North and
55° South. If this is not possible problems occur especially when at least four
satellites for positioning have to be found.
The antenna/converter unit can be mounted on a pole with a diameter up to 60 mm or
on a wall. A 50 cm plastic tube, two holders for wall-mounting and clamps for pole-
mounting are added to every GPS170. A standard coaxial cable with 50 Ω impedance
should be used to connect the antenna/converter unit to the receiver. The maximum
length of cable between antenna and receiver depends on the attenuation factor of the
used coaxial cable.
Example:
Up to four GPS170 receivers can be run with one antenna/converter unit by using the
optional antenna splitter. The total length of one antenna line between antenna,
splitter and receiver must not be longer than the max. length shown in the table above.
The position of the splitter in the antenna line does not matter. hen installing the
high voltage protector CN-UB/E (CN-UB-280DC) be aware to set it directly after
reaching indoor. The CN-UB/E is not for outdoor usage.
20
Type of cable diameter
Ø [mm]
Attenuation at 100MHz
[dB]/100m
max. lenght
[m]
RG58/CU 5mm 15.9 300 1
RG213 10.5mm 6.9 600 1
1)This specifications are made for antenna/converter units produced after January, 2005
The values are typically ones; the exact ones are to find out from the data sheet of the
used cable.