Siemens RUGGEDCOM RX1100P, Руководство по установке

Страница: 32 / 50

Chapter 3
Communication Ports
RUGGEDCOM RX1100P
Installation Guide
26 Lightning Considerations
Dielectric Type Time Delay(ns/ft) PropagationVelocity(% of c)
Solid Polyethylene (PE) 1.54 65.9
Foam Polyethylene (FE) 1.27 80.0
Foam Polystyrene (FS) 1.12 91.0
Air Space Polyethylene (ASP) 1.15-1.21 84-88
Solid Teflon (ST) 1.46 69.4
Air Space Teflon (AST) 1.13-1.20 85-90
Section 3.8.3.3
Lightning Considerations
Although it is not possible to protect the antenna from a direct lighting strike, the antenna and connected
components can be protected from secondary affects through installation location and protection devices.
Install the antenna at least 15 meters away from and lower than any structures that attract lightning. GPS
antenna damage is usually not the result of a direct lightning strike, but due to high currents induced by the
effects of a lightning strike on a nearby structure. Siemens also recommends installing lightning arrestors in the
antenna line to protect the receiver and connected devices. If a lightning arrestor is installed it is important to
ensure that it has a low impedance path to ground.
Section 3.8.3.4
Line Amplification and Filtering
Although an active antenna has gain, depending on the length of the coaxial cable used it may not be enough in
which case a line amplifier will be required as well.
Most active antennas include filters. However, if there is a high potential for electromagnetic interference, such
as from the near field of a radio transmitter, though the antenna system, additional antenna line filtering may be
necessary.
Section 3.9
RS232 External Modem Ports
The optional RS232 external modem card provides all of the handshaking signals required to control an external
modem via a female DB9 connector.
The following is the pin-out for DB9 ports operating in RS232 mode: