Sony Ericsson TT4031 (SE-GM29) - Manual (Page 45)

Owner’s Manual Rev 1.0 Page 45 of 45
In any event, you should contact your local 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 local antenna manufacturer might
be able to design a special antenna suitable for your the application.
5.4.2 Antenna Type
Make sure that you choose the right type of antenna for the modem.
Consider the following requirements:
the antenna must be designed for the dual frequency bands in
use: EGSM/GSM900/1800;
the impedance of the antenna and antenna cable must be 50 Ω;
the antenna output-power handling must be a minimum of 1 W;
the VSWR value should be less than 3:1 to avoid damage to the
modem.
5.4.3 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 50 cm.
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 1 W. RF field strength varies with
antenna type and distance. At 10 cm from the antenna the field strength may
be up to 70 V/m and at 1m it will have reduced to 7 V/m.
5.4.4 The Antenna Cable
Use 50 Ω impedance low-loss cable and high-quality 50 Ω impedance
connectors (frequency range up to 2 GHz) 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.