3 Tips to Avoid Vandalism to GSM/GPRS Antennas in M2M Applications
Remote installations fitted with GSM/GPRS telemetry equipment often comes under attack by groups such as bored youths and local hooligans congregating in specific areas.
Locations with telemetry equipment include vending machines, bus stops fitted with RTPI (real time passenger information) equipment, utility boxes for acting as a local information gateway from homes back to service providers and remote weather stations for transmitting local weather to a centralised point. All have a critical requirement for ensuring products are built to last in their particular environment and wireless connectivity over a GSM or GPRS network is becoming a low cost way of interacting with remote sites.
Use a Low Profile Antenna
Although most GSM/GPRS antennas are vertically polarised, a growing trend of low profile antennas are being introduced to the market. These are designed to be fitted low down on the casing and secured via a through hole bolt which passes through a hole on the enclosure. This ensures the antenna cannot be removed without access to the inside of the enclosure and no cabling is visible. Good quality products such as the Siretta Antenna Tango 1 and Tango 2 series are designed with robust plastic enclosures to give adequate protection against all but the most sustained attack. These offer quad band GSM/GPRS cellular connectivity and often 3G and 2.4GHz operation as well. Siretta Antennas also produce a Tango 5 series which provides GPS (satellite tracking) capability as well.
Elevate the Antenna
GSM/GPRS communications operates on a line of site principle so it is a useful idea to raise the height of the antenna above ground level if possible. This gives the additional plus of keeping the antenna out of arms length whilst improving communication at the same time.
Cable in these types of installations can be routed up bus stop poles or underground to minimise other parts of the equipment being targeted. A good example of this is the Oscar 1 series by Siretta Antennas. This is supplied with a bracket for fixing to mounting poles sides of buildings and 5 metres cable which is sufficient for the majority of installations but can be extended if necessary.
For weak signal areas such as remote sites with perhaps one cell site in a locality, a Yagi antenna such as the 900MHz Oscar 3 from Siretta can be installed at a high point and pointed in the direction of the cell site.
Hide the Antenna
Providing the equipment is not inside a metal enclosure (RF signals do not transmit well inside these), internal antennas can be used. These are available with varying lengths of cable according to the distance between antenna mounting site and telemetry unit. If they are going inside equipment, a less rugged, non waterproof antenna could be used. Siretta Antennas produce a neat range of embedded antennas or adhesive antennas to fix inside enclosures.
The above pointers should be useful in overcoming objections often given by end customers who are concerned about longetivity and robustness of products in the field. Providing field trials are completed satisfactorily, they should provide a practical compromise to maintaining suitable signal levels whilst not being seen as weak spot to a design.
Locations with telemetry equipment include vending machines, bus stops fitted with RTPI (real time passenger information) equipment, utility boxes for acting as a local information gateway from homes back to service providers and remote weather stations for transmitting local weather to a centralised point. All have a critical requirement for ensuring products are built to last in their particular environment and wireless connectivity over a GSM or GPRS network is becoming a low cost way of interacting with remote sites.
Use a Low Profile Antenna
Although most GSM/GPRS antennas are vertically polarised, a growing trend of low profile antennas are being introduced to the market. These are designed to be fitted low down on the casing and secured via a through hole bolt which passes through a hole on the enclosure. This ensures the antenna cannot be removed without access to the inside of the enclosure and no cabling is visible. Good quality products such as the Siretta Antenna Tango 1 and Tango 2 series are designed with robust plastic enclosures to give adequate protection against all but the most sustained attack. These offer quad band GSM/GPRS cellular connectivity and often 3G and 2.4GHz operation as well. Siretta Antennas also produce a Tango 5 series which provides GPS (satellite tracking) capability as well.
Elevate the Antenna
GSM/GPRS communications operates on a line of site principle so it is a useful idea to raise the height of the antenna above ground level if possible. This gives the additional plus of keeping the antenna out of arms length whilst improving communication at the same time.
Cable in these types of installations can be routed up bus stop poles or underground to minimise other parts of the equipment being targeted. A good example of this is the Oscar 1 series by Siretta Antennas. This is supplied with a bracket for fixing to mounting poles sides of buildings and 5 metres cable which is sufficient for the majority of installations but can be extended if necessary.
For weak signal areas such as remote sites with perhaps one cell site in a locality, a Yagi antenna such as the 900MHz Oscar 3 from Siretta can be installed at a high point and pointed in the direction of the cell site.
Hide the Antenna
Providing the equipment is not inside a metal enclosure (RF signals do not transmit well inside these), internal antennas can be used. These are available with varying lengths of cable according to the distance between antenna mounting site and telemetry unit. If they are going inside equipment, a less rugged, non waterproof antenna could be used. Siretta Antennas produce a neat range of embedded antennas or adhesive antennas to fix inside enclosures.
The above pointers should be useful in overcoming objections often given by end customers who are concerned about longetivity and robustness of products in the field. Providing field trials are completed satisfactorily, they should provide a practical compromise to maintaining suitable signal levels whilst not being seen as weak spot to a design.
