Standard Horizon GM29 manual Possible communication disturbances include the following

GM29 INTEGRATOR’S MANUAL

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.

4.3.2 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 50Ω;

•the antenna output-power handling must be a minimum of 2W;

•the VSWR value should be less than 3:1 to avoid damage to the modem.

4.3.3Antenna 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.

4.3.4 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.

4.3.5 Possible Communication Disturbances

Possible communication disturbances include the following:

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LZT 123 7361 R1A