NT910G
User Manual - Telic AG
Pg 25
▪
Securely attach the LT910 E Terminal modem to the host application using two 3mm diameter
pan-head screws.
6.3
Antenna
6.3.1 GENERAL
The antenna is the component in your system that maintains the radio link between the network and
the modem. Since the antenna transmits and receives electromagnetic energy, its efficient function will
depend on:
▪
the type of antenna (for example, circular or directional);
▪
the placement of the antenna;
▪
Communication disturbances in the vicinity of the antenna.
The following sections address issues concerning antenna type, antenna placement, antenna cable,
and possible communication disturbances. In any event, you should contact your antenna
manufacturer for additional information concerning antenna type, cables, connectors, antenna
placement, and the surrounding area. You should also determine whether the antenna needs to be
grounded or not. Your antenna manufacturer might be able to design a special antenna suitable for
the application.
6.3.2 ANTENNA TYPE
Make sure that the selected antenna meets the requirements specified in Section 4.2 (“Antenna
Co
nnector”).
6.3.3 ANTENNA PLACEMENT
The antenna should be placed away from electronic devices or other antennas. The recommended
minimum distance between adjacent antennas, operating in a similar radio frequency band, is at least
50cm. If signal strength is weak, it is useful to face a directional antenna at the closest radio base
station. This can increase the strength of the signal received by the modem. The modem’s peak output
power can reach 2W. RF field strength varies with antenna type and distance. At 10cm from the
antenna the field strength may be up to 70V/m and at 1m it will have reduced to 7V/m. In general, CE-
marked products for residential and commercial areas, and light industry can withstand a minimum of
3V/m.
6.3.4 THE ANTENNA CABLE
Use 50Ω im
pedance 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
