Finding a Tunnel’s Sweet Spot

Aug. 21, 2008
Security forces and law enforcement agencies depend as much on wireless communications as teenagers and plugged-in executives.

So what will they do when an emergency strikes in a tunnel or mine, and their communications start breaking down? (Radio signals have a hard time traveling through deep tunnels and even long corridors in some buildings.) Researchers at NIST are trying to find a solution, a sweet spot in the frequency range at which signals travel several times farther than at other frequencies. For a typical subway tunnel, researchers determined the sweet spot is between 400 MHz and 1 GHz. They also believe tunnels act like giant waveguides, with the tunnel dimensions, materials, and flatness of the floor determining their effects on RF signals. And at the sweet spot, the shape of the tunnel reduces losses caused by RF signals being absorbed or scattered by structures. NIST personnel hope their work will lead to wireless communication devices for search and rescue robots used in tunnels and mines.

MORE INFO
National Institute of Science and Technology Gaithersburg, MD nist.gov

 

An electronics engineer aligns antennas in an abandoned California silica mine during a NIST study looking for frequencies that best transmit radio signals.

Sponsored Recommendations

NEW Low Profile, Ultra Compact Power Supplies

March 13, 2024
Learn more HERE about Altech's Power supplies!

Altech's Liquid Tight Strain Relifs Catalog

March 13, 2024
With experienced Product Engineers and Customer Service personnel, Altech provides solutions to your most pressing application challenges. All with one thought in mind - to ensure...

Industrial Straight-Through Cable Gland

March 13, 2024
Learn more about Altech's cable glands and all they have to offer for your needs!

All-In-One DC-UPS Power Solutions

March 13, 2024
Introducing the All-In-One DC-UPS, a versatile solution combining multiple functionalities in a single device. Serving as a power supply, battery charger, battery care module,...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!