Accessories, Antenna type, Antenna placement

GTR64

http://www.matrix.es/GTR64

7.3.2 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 one of the frequency bands in use; please ask your network provider for more informations:

•GSM 850/900 MHz

•GSM 1800/1900 MHz;

•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.

7.3.3 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.

7.3.4 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.

7.3.5 Possible communications disturbances

Possible communication disturbances include the following:

•Noise can be caused by electronic devices and radio transmitters.

•Path-lossoccurs as the strength of the received signal steadily decreases in proportion to the distance from the transmitter.

•Shadowing is a form of environmental attenuation of radio signals caused by hills, buildings, trees or even vehicles. This can be a particular problem inside buildings, especially if the walls are thick and reinforced.

•Multi-path fading is a sudden decrease or increase in the signal strength. This is the result of interference caused when direct and reflected signals reach the antenna simultaneously. Surfaces such as buildings, streets, vehicles, etc., can reflect signals.

•Hand-overoccurs as you move from one cell to another in the GSM network. Your mobile application call is transferred from one cell to the next. Hand-over can briefly interfere with communication and may cause a delay, or at worst, a disruption.

7.4 Accessories

The GTR64 has been type approved together with a range of accessories including:

Power supply, all type of antennas (indoor, outdoor, high gain, etc…), cables and DIN adapter

GTR64 Integrators Manual V.1.2 Pag. 29

Preliminary. Subject to change without prior notice