Poynting Innovations has recently consolidated its extensive expertise in the field of underground communications and is pleased to announce the creation of a new engineering division - Network Solutions. This division is focussed on planning cost effective wireless telecommunications solutions for the mining sector.
Drawing on many years of experience in underground radio frequency (RF) propagation (including specialist product development) Network Solutions provides potential clients with the following services:
* Analysis of overall communication needs, and the generation of a detailed user requirement specification.
* Investigation into current and future wireless technologies and standards that will ensure a cost effective end solution.
* Radio network planning, including path profile and area coverage predictions to ensure optimal network design.
* Radio coverage surveys to validate the RF network performance.
* Specify, design and supply of custom antenna to meet unique underground requirements.
* Complete specification of the resulting RF network design, including a cost benefit analysis of the solution.
The above services are available across multiple radio technology platforms including but not limited to: Wireless LAN (WLAN), IEEE 802.11a/b/g, Bluetooth, GSM, Tetra and V/UHF.
Poynting Innovations Network Solutions competitive advantage lies in the fact that in addition to their extensive range of technical expertise, they provide the client with a single professionally managed interface. The main focus is on establishing long term client relationships.
According to Anthony Selikow, Manager of Network Solutions, these services, combined with Poynting`s unique range of antennas specifically designed for communication in mines or tunnels, makes them the obvious choice for all underground communication requirements.
The first 2 antennas that were developed were for the 2400 MHz band and consisted of helical antennas that are either two-way or one-way. The 2m two-way antenna consists of two helices that are arranged in such a way that the radiation pattern has two principle lobes each pointing 180 degrees from each other. Thus, this antenna is ideal for providing coverage down long straight tunnels (road, rail or mine tunnels). The antenna is enclosed in a rugged, waterproof plastic housing (with a diameter of 120mm) and is therefore able to withstand the harsh environment for which it was designed.
The other antenna is an uni-directional version constructed using one helix only. Two, one-way antennas` can be joined using a splitter to construct an access point at a tunnel junction or bend.
The gain for the two-way 2.4 GHz antenna is between 16 and 17 dBi, and the typical beamwidth 24-27 degrees.
Measurements were performed in the AngloGold Kopanang Mine in Orkney on two occasions and the results exceeded all expectations. Two two-way antennas were used for space diversity and the communication range exceeded 400m in both directions (800m of haulage for one access point).
This extensive coverage achievable with the MinePoynt antenna results in the installation cost (per meter of tunnel) of a wireless system that is lower than the cost of installing a leaky feeder system.
The wireless system uses the IEEE 802.11 standard and hence can support a data rate of 11 Mbit/s (a data rate that is considerably higher than the contemporary leaky feeder system). The system can carry data, voice (using IEEE 802.11 VoIP) and video.
Normal quality video (as advertised on TV) requires about 2 Mbit/s using MPEG2 compression. Video of this quality is seldom required in an industrial application and there is therefore scope to reduce the frame rate nd resolution of the video. This reduction in video quality would allow many simultaneous video, data and voice channels to be communicated across a single 11 Mbit/s link.
IEEE802.11 WLAN systems are cellular in nature and allow users to roam from access point to access point. At the request of Gerbrand Steyn of Grintek Communication Systems, antenna prototypes for the 1800 MHz frequency were developed. GCS and Siemens ran successful trials in the Du Toits Kloof Tunnel. A two-way antenna was placed at the centre of the tunnel and the coverage of 2.5 km to each side was achieved, this resulted in the complete length of the tunnel being covered.
A 17 dBm (50mW) input signal was used and a -85dBm received signal was measured at the mouth of the tunnel. This receive signal is excellent for cellular reception. They observed a drop of about 20 dB in signal strength when two trains pass each other, thereby blocking a large portion of the tunnel. Gerbrand Steyn believes that a space diversity installation using 2 antennas on opposite walls, in the middle of the tunnel will ensure communications under worst case traffic conditions.
Vodacom is also undertaking underground trials for cellular communication in mines at an AngloGold mine. Gordon Mayhew-Ridgers and Paul van Jaarsveld manage this project at head office.
Kenneth Morrell, MD of Mine Radio Systems, invited Poynting to give a presentation of mining related experience and antennas to representatives of the company. Mine Radio Systems is a Canadian based company with branches in South Africa and Australia. Mark Montpellier, System Specialist at MRS, indicated that they have a similar project in Canada that will benefit greatly in using these antennas. Patrick Waye, president of MRS would like to see the MinePoynt integrated with their Ethernet Leaky Feeder system. They also foresee great demand for underground antennas in Australia.
Please contact Anthony Selikow at anthony.selikow@poynting.co.za or more information.
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