CEP Terminals CT63 NG, Руководство пользователя

Страница: 25 / 27

25
6.3.4 The antenna cable
Use 50Ω impedance low-loss cable and high-quality 50Ω impedance connectors (frequency range up to
2GHz) to avoid RF losses. Ensure that the antenna cable is as short as possible. The Voltage Standing-
Wave Ratio (VSWR) may depend on the effectiveness of the antenna, cable and connectors. In addition,
if you use an adapter between the antenna cable and the antenna connector, it is crucial that the
antenna cable is a high-quality, low-loss cable. Minimize the use of extension cables, connectors and
adapters. Each additional cable, connector or adapter causes a loss of signal power.
6.3.5 Possible communications disturbances
Possible communication disturbances include the following
:

Noise can be caused by electronic devices and radio transmitters.

Path-loss occurs as the strength of the received signal steadily decreases in proportion to the distance
from the transmitter.

Shadowing is a form of environmental attenuation of radio signals caused by hills, buildings, trees or even
vehicles. This can be a particular problem inside buildings, especially if the walls are thick and reinforced.

Multi-path fading is a sudden decrease or increase in the signal strength. This is the result of interference
caused when direct and reflected signals reach the antenna simultaneously. Surfaces such as buildings,
streets, vehicles, etc., can reflect signals.

Hand-over occurs as you move from one cell to another in the GSM network. Your mobile application call
is transferred from one cell to the next. Hand-over can briefly interfere with communication and may
cause a delay, or at worst, a disruption.