The SIAMnet is a communication system that is designed for underground mines allowing people and computers to communicate with each other.
The propagation of radio waves is negatively impacted by the small mine tunnels and performance quickly deteriorates.
The SIAMnet communication system distributes the radio wave signals throughout the mine and reestablishes communication among users whether they are located at the surface or underground.
Two-way voice communication was the primary use for a communication system prior to the introduction of computers into mines. Nowadays, data communication is of utmost importance as it is used for process control, ventilation on demand, blasting systems, seismic activity monitoring, tagging, emails, Internet and a number of other applications.
The SIAMnet is well suited to answer those needs due to its high data communication capabilities. The system is easy to configure, install and service. It is based on the cable television standards and is the most cost effective system when it comes to data communication for underground mining operations.
The SIAMnet is a Distributed Antenna System, based on the CATV standards and utilizes commercially available components. It uses coaxial cable to transport the signal throughout the mine. Splitters are then used to divide the network into branches and to feed antennas or network devices. High frequency 800MHz radio signals propagate better into tunnels than lower frequency VHF. Antennas are also shorter and their installation is non-obstructive.
Omnidirectional antennas are installed at tunnel intersections and cover 360 degrees. Directional antennas cover a single tunnel but at an increased distance. These antennas are used for simultaneous voice and data communication. Since the radio coverage is provided by antennas and not by the cable, the cable may be protected using conduits or shotcrete. The system is more reliable since incidents do sometimes occur in a mine. Amplifiers are installed at predetermined distances to compensate for cable losses and they are powered from the cable. There is no need to install a separate AC power line.
The basic SBDA 2 amplifier operates within the 800MHz LMR band and supports the voice and mobile data communication. The add-on CMA/SDA companion module operates in the cable modem band, below 200MHz, and supports high speed data communication and video. The SDA circuitry provides diagnostic and remote configuration capabilities.
The SIAMnet supports multiple simultaneous conversations, up to 32 channels. It is compatible with either the analog or digital 800MHZ communication technologies. There are two types of radios that can be used with the system: mobile radios for vehicular applications and portable radios for personal use.
The system may be configured to operate in a conventional mode or the more powerful trunking modes. Trunking allows a large number of user groups to share the system and is not limited by the number of voice channels. It is a much more efficient method of using the same infrastructure and therefore increases the overall effectiveness of the system. Trunking allows private conversations between users no matter where they are. A telephone interface may also be provided so that users can receive or place telephone calls outside of the mine.
?800 MHz frequencies propagates better and further into undergound mines tunnels than VHF and UHF.
Analog Two-Way radios with up to 32 simultaneous conversations.
?Conventional or Trunking systems at the surface or Underground.
?Digital 800 MHz radio using the P25 universal protocol.
Telephone Interconnect permiting receiving or making external calls.