Behind the Scenes in Closed Space Communications

The implementation process for Tunnel Radio’s custom two-way radio and tracking systems

For workers in underground and remote environments like tunnels, mines, ships, and railroads, reliable communication is paramount to worker efficiency and safety. Because underground range is affected by the height, width, and number of turns in the enclosed area, these closed-space environments by their nature block radio signals, preventing effective underground communication.

Some have tried to address this problem by placing hard-wired phone systems at strategic locations. The use of these systems has proven to be cumbersome, and often does little to help in emergency situations. Other systems have been developed that rely on wireless hotspots, but may lack the necessary full radio coverage of an entire site.

Leaky feeder-based RF coverage is a well-established technology that provides continuous coverage by allowing radio signals to “leak” from the entire length of the cable, much like a sprinkler hose. As radio signal strength diminishes along the cable length, amplifiers boost signal strength to support another run of cable. Power is provided by a base interface unit that puts DC on the cable. This set-up makes the system very extensible, cost-effective, and easy to maintain.

Specializing in two-way radio communication, as well as tracking systems, Tunnel Radio primarily serves clients in mining, rail and critical infrastructure (tunnels, dams, wastewater treatment facilities, etc.). As part of their full-service approach, Tunnel Radio not only designs, engineers and manufactures custom radio communication solutions, but also provides installation and training services. Because every situation, every tunnel is different, its radio solutions are tailor-made for the individual client.

How it’s Made

While every project and solution is unique, the leaky feeder-based RF implementation process follows these same six phases:

1. Site Visit

Every project begins with identification of the problem, e.g., an issue with underground communication, high-loss areas lacking a strong line of communication for their radio or tracking systems, or other identified safety and logistics concerns.

Once the core problem is identified, a site visit is the most productive way to understand the parameters of the project. Depending on the complexity of the project, a site visit will usually take one to three days and include a propagation analysis, path analysis and a review of the current infrastructure in place in order to determine the best direction forward.

2. Engineering & Design

Next comes system design. RF engineers and technicians take the site’s infrastructure into account, along with data collected during the site visit, to design and develop a custom radio communications solution for the client.

3. Quote & Proposal

With a design in place, the wireless communication provider will provide a formal quote and proposal to the client based on the type of equipment and actual quantities to be used in the build. This quote will include both the equipment needed, as well as installation costs.

4. Manufacturing

Once the proposal is accepted and processed, the build phase begins. Lead times range from a couple of days to six weeks for a full product suite, even with the supply chain issues that have arisen since 2020.
As an ISO-9001 certified company, Tunnel Radio designs, engineers and manufactures its entire product line, from radio interface equipment and amplifiers for voice comms to active RFID tracking systems. They also design and build custom software for monitoring and tracking.

5. Installation

After the system components are built and bench-tested , it’s time for installation. Technicians travel to the implementation site and work with the client’s on-site staff to ensure that the coax cabling, in-line amplifiers and antennas are installed to spec. Projects typically span 1-10 miles and technicians can install approximately one mile of system for every 4-5 hours of work.

6. Testing & Training

Once the system is installed, a full test and tune is completed to make sure the system is properly set and operational. Technicians will check radio frequencies and ensure power levels are set correctly throughout the entire system.

On-site training for technicians and other staff who will be supporting the new system follows installation. If clients are in need of assistance, Tunnel Radio is there with 24/7 customer support from techs who have access to documentation of each unique system.

About Tunnel Radio

Tunnel Radio of America is an ISO-9001 certified manufacturer and Women-Owned Small Business, headquartered in Corvallis, Oregon. For almost 35 years, Tunnel Radio has distinguished itself as a trusted designer, manufacturer and installer of specialized radiating-cable antenna systems for otherwise unreachable areas, including dams, mines, tunnels, basements and cargo ships. Tunnel Radio’s wireless radio and data systems can be found in every Class I railroad in North America—as well as some of the largest coal and hard rock mines in the U.S., Canada and Australia. They also have completed projects as a contractor or subcontractor for federal, state, municipal and industrial clients, nationwide. For more information, visit www.tunnelradio.com/contact.