Successful Tunnel Communications

Radiocoms Systems Ltd is a specialist hire and sales company for two-way radio communication solutions. Radiocoms Systems Ltd was originally founded in 1974 and has become a leading provider of communications, supplying the Construction, MOD, Fire Service, Petro-chem and Off-shore industries.

Radiocoms has built its name around quality, reliability and professionalism throughout the UK and Europe by providing a solutions-oriented approach to every project undertaken.

Within each industry sector, there is now an increasing requirement for tunnel communication systems that can encompass not only two-way radios but provide telemetry remote control and monitoring.

‘Leaky Feeder’

Above ground, two-way radio communication is feasible by using a surface antenna system to boost the radio signal. However, this process does not work in underground situations such as a tunnel because the radio frequency suffers from a high level of attenuation. The solution for this is replacing the antenna system with a cable that is designed to leak the radio frequency at regular intervals, allowing the radio transmissions to continue; this cable is known as ‘Leaky Feeder’.

The so called ‘Leaky Feeder’ system can support two-way voice and data applications as well as full telemetry control of remote equipment.

Provided that the leaky feeder system in place is of sufficient quality, it will enhance the functionality of the system through a SCADA (Supervisory Control and Data Acquisition) interface package.

Benefits:

• Remote control of fans and pumps
• Adjustment of ventilation flow control
• Allows Gas Detection Monitoring
• Allows quick and easy relocation of fans and provides control once it is connected to the leaky feeder

Inherent Signal Loss Compensation

Dependant upon the length of the cable run, there may be an inherent signal loss; however, this can be compensated with the use of bi-directional amplifiers. These amplifiers are used to maintain consistent signal strength throughout the network.

System Configuration

The head-end equipment operates the leaky feeder system by connecting to the leaky feeder cable and a surface antenna (for above ground communications). This provides modulation and demodulation of the radio signals, splitting and combining of multiple channels, powering the leaky feeder network and providing the necessary diagnostics in the control room via a transparent link.

Who will benefit from a Leaky Feeder System?

With the ever increasing demands of Health & Safety, terrorist attacks, automation and the need to communicate in the most extreme environments; tunnel communications has never been so important, so whenever users are working in a tunnel environment a reliable and high quality communication system will be required.

Typical uses:

• Train Tunnels
• Viaducts
• Road Tunnels
• Mines
• Cabling Tunnels
• Bridges

Two-Way Radio Options

‘The leaky feeder cable will always remain the back bone of any tunnel communication system. The only variations will be the equipment that utilise it and the different radio handsets available.’ As commented by Richard Hemmings, Radiocoms Tunnel Communication Specialist.

As Radiocoms Systems Ltd is an independent supplier of two-way radios, there are numerous radio options and manufacturers to choose from, depending on the user preference and suitability for the application.

Typically, the radios used are enabled with a 5-tone facility, as this allows the radio user to identify the ‘caller’ via the radio display. Also, with the advent of channel annunciation and call vibrate the radios are becoming more adapted to working underground and providing simple and safe operation for the user.

Why Use Radiocoms?

‘Radiocoms are a solutions-orientated company that has a wealth of experience of providing quality tunnel communication systems. With plant equipment technology and wireless communications advancing dramatically over the last 10 years, the need for automation of remote devices is an ever increasing requirement. Radiocoms is able to bring together existing tunnel communication technologies (leaky feeder) and merge them with the demands of today to ensure suitable tunnel communication systems are effective and delivered on time.’ (Richard Hemmings, Radiocoms Tunnel Communication Specialist.)

For consultation, tenders or general information on tunnel communications, please contact Richard Hemmings at:

Radiocoms Systems Ltd, 170a Oval road, Croydon, Surrey, CR0 6BN, Tel: 0208 6801585, Fax: 0208 686 9433