Distributed Antenna System (DAS)

The SIAMnet backbone is often referred to as a DAS, which stands for “Distributed Antenna System”. The DAS is used to transport the radio signals (RF) and provide radio coverage along the drifts.

Coaxial Cable

The DAS has been designed to operate in the 600 to 900 Mhz bands, which are the frequencies that propagate the best in underground mines.

The DAS infrastructure is based on a 75 ohms technology, which is used throughout the world in the CATV cable industrie.  This technology is widely available throughout the world at a reasonable cost.

DAS Infrastructure Inside the mine, the SIAMnet coaxial cable is installed along the drift where RF coverage is required. At predetermined locations, antennas are connected to the DAS to provide local RF coverage.

In certain applications, the cable can simply be hidden in the electrical rack behind service pipes or even coming from drifts below or above the area via raises or shafts.  This way, the cable is protected against damages due to explosions or accidents.

Since the DAS is partially composed of CATV parts, the SIAMnet is very cost effective. For the most part, DAS equipment is readily available worldwide and can be used to expand or repair a SIAMnet.

Power supplies, splitters and connectors may be purchased locally while amplifiers and antennas are available from any SIAMtec distributor.

Contrary to the leaky cable technology, the DAS cable is 100% shielded (sealed) and does not radiate RF energy. As a result, it can be protected using metallic pipe against physical damage and can be used in areas such as secondary explosion, development blast, and so on.

Various types of CATV cables are available; for example, amoured, waterproof and underground cables, which can be installed wherever needed. All cables are waterproof and 100% shielded to ensure the proper operation of the system in any condition.

The DAS is designed to provide radio coverage only to those locations as specified by the customer. There is no signal loss in undesired areas or in cables returning to a cross point (intersection of two roads).

By strategically placing omni-directional antennas at the cross roads, radio coverage is provided in the main drift and also in the cross drift, and this, at no additional cost to the customer.

Power supplies, splitters and connectors may be purchased locally while amplifiers and antennas are available from any SIAMtec distributor.