Integrator's Manual GR47/GR48

8. HINTS FOR INTEGRATING THE RADIO DEVICE

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.