Ross 4500DR-104-07, User Manual, Page: 133 / 161

SRG-4500 User Guide (v7.0) GPS Option • 133
GPS Option
This chapter provides information on installing the GPS option for your SRG-4500.
Surge Protection
Surge protection may be required if rooftop antennas are being connected, in order to meet the regulations and
standards for lightning protection in the countries where the end-product will be installed.
Lightning protection means actually a protection of people and buildings. If the antenna is hit by a direct lightning
strike, your least worry should be damage of the GPS receiver. You should worry about the lightning energy, which
can enter the building and directly strike a person or cause fire. A lightning protection shall be mounted at the place
where the antenna cable enters the building. The primary lightning protection must be capable of conducting all
potentially dangerous electrical energy to PE (Protective Earth). In case of a rooftop antenna, a coax-cable insert is
needed. Ross Video doesn't sell these, but there are many companies, which do. The antenna on the roof can't be
protected against a direct lightning strike. It will just melt if hit by a direct lightning strike.
Rooftop antenna should be installed by experienced electricians, who are familiar with the local regulations and
standards. Not following these regulations may lead to legal actions and rejection of insurance coverage in case of
damage from lightning. Make sure to choose a lightning protector with DC-pass and suitable for the GPS frequency
range (1.575GHz) with low attenuation.
Notes on Installing an Antenna
Keep the following in mind before installing your antenna and connecting it to your SRG-4500:
• Ensure the Option Key for the GPS feature is enabled on the SRG-4500. Refer to the section “
Option Enable
Menu ” on page 88 for details.
• The antenna must be positioned away from any buildings or surfaces that could cause reflections to be received
by the antenna.
• If you are mounting the antenna on a wall bracket, this assembly must be placed at the top of the wall, so as to
gain a clear view of the sky above.
• The GPS antenna cannot be mounted indoors; not even against a window, even one without an anti-glare coating.
• Because the coaxial cable has different connectors at each end, be sure to install it in the correct direction.
• When routing the coaxial cable, be sure to avoid tight corners, where the cable could become kinked. If the
low-loss coaxial cable is being installed, this has a much larger diameter and is of a stiffer construction than the
standard cable, and will therefore be very difficult to route around tight corners.
• Provide adequate cable strain relief at the SRG-4500.
System Requirements
The SRG-4500 requires an Option Key to enable the GPS sub-system. Additional optional GPS components are
available when the GPS Option is ordered as part of your system.
The system works best with a GPS signal level between -125dBm and -117dBm at the SMB plug at the rear of the
unit. It can achieve cold start with a -147dBm signal.