Sony Ericsson GR47/GR48 - Manual (Page 58)

8. HINTS FOR INTEGRATING THE RADIO DEVICE
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LZT 123 7589 R1A
8.3 Antenna
8.3.1 General
The antenna is the component in your system that maintains the radio link
between the network and the radio device. 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 in which the antenna
operates.
In the sections below, issues concerning antenna type, antenna placement,
antenna cable, and possible communication disturbances are addressed.
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.
8.3.2 Antenna Type
Make sure that you choose the right type of antenna for the radio device.
Consider the following requirements:
• the antenna must be designed for the dual frequency bands in use:
E-GSM900/GSM1800 for the GR47 and
GSM 850/GSM1900 for the GR48;
• the impedance of the antenna and antenna cable must be 50
Ω
;
• the antenna output-power handling must be a minimum of 2 W;
• the VSWR value should be less than 3:1 to avoid damage to the radio
device.
8.3.3 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 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 radio device.
The radio device’s peak output power can reach 2 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.