Symmetricom Time Server Manual Do Utilizador
6000-100Ch2.fm Rev. D
TimeVault™ User’s Manual
2-13
Site Preparation
Chapter 2: Installation and Start-Up
2.1.3
Antenna Information
Voltage Requirement and Signal Levels
TimeVault requires a 12 V antenna. Any antenna that
does not support 12 V may be severely damaged if
plugged into TimeVault.
does not support 12 V may be severely damaged if
plugged into TimeVault.
The GPS Synchronized Receiver, integral to TimeVault,
operates on the L1 (1575.42 MHz) signal and the C/A
code (1.023 MHz bit rate) with a minimum signal level
of –162.0 dBW and a maximum signal level of
–137.0 dBW. The antenna system supplied is designed to
provide the proper signal levels to the receiver with the
cable length supplied.
operates on the L1 (1575.42 MHz) signal and the C/A
code (1.023 MHz bit rate) with a minimum signal level
of –162.0 dBW and a maximum signal level of
–137.0 dBW. The antenna system supplied is designed to
provide the proper signal levels to the receiver with the
cable length supplied.
Use of a Splitter
To run multiple units with a single 12 V antenna, use a splitter. Do not use a BNC “T”
connector, which doesn’t provide the proper voltage the unit needs to operate.
connector, which doesn’t provide the proper voltage the unit needs to operate.
Lead-In Cable
The L1 GPS antenna is designed to operate with up to 200 ft (60.96 m) of RG-59 coax
cable. The optional Down/Up Converter is designed to operate with up to 1,500 ft
(457.2 m) of RG-58 coaxial cable. For details and illustrations on cabling, see page 2-15.
cable. The optional Down/Up Converter is designed to operate with up to 1,500 ft
(457.2 m) of RG-58 coaxial cable. For details and illustrations on cabling, see page 2-15.
2.1.4
GPS Roof-Mounted Antenna Installation
When selecting a site for the standard outdoor antenna, find an outdoor location that
provides full 360-degree visibility of the horizon. In most cases, this means locating the
antenna as high as possible. Any obstruction will degrade unit performance by blocking
the satellite signal or causing a reflection that cancels some of the signal. Blocked signals
can significantly increase the time for satellite acquisition, or prevent acquisition all
together.
provides full 360-degree visibility of the horizon. In most cases, this means locating the
antenna as high as possible. Any obstruction will degrade unit performance by blocking
the satellite signal or causing a reflection that cancels some of the signal. Blocked signals
can significantly increase the time for satellite acquisition, or prevent acquisition all
together.
Mast Mounting
Mast top mounting is the preferred mounting method and
special brackets are provided to mount the antenna to a pipe or
the peak of a building. The antenna mounting mast should be
2-inch (5.08-cm) water pipe or conduit. The mast must be rigid
and able to withstand high winds without flexing. Guy wires
may be used to stabilize a mast longer than 10 ft (3.048 m)
special brackets are provided to mount the antenna to a pipe or
the peak of a building. The antenna mounting mast should be
2-inch (5.08-cm) water pipe or conduit. The mast must be rigid
and able to withstand high winds without flexing. Guy wires
may be used to stabilize a mast longer than 10 ft (3.048 m)
Multipath cancellation is caused by reflected signals that
arrive at the antenna out of phase with the direct signal.
Reflective interference is most pronounced at
arrive at the antenna out of phase with the direct signal.
Reflective interference is most pronounced at
low elevation
angles from 10 to 20 degrees above the horizon. You may
12 V GPS Antenna
Coaxial Cable
Threaded Cable
Housing
Housing
Figure 2-1 Basic Antenna
Components
12 V GPS
Mast
Figure 2-2: Mast Mounting
Illustration
Antenna