Telecommunications – Transmitter and receiver at separate stations – Plural transmitters or receivers
Reexamination Certificate
1998-07-03
2001-02-27
Vo, Nguyen T. (Department: 2682)
Telecommunications
Transmitter and receiver at separate stations
Plural transmitters or receivers
C455S011100
Reexamination Certificate
active
06195561
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to radio systems, and specifically to an antenna system for a radio system which is designed to operate in shielded environments, such as mines and tunnels.
BACKGROUND OF THE INVENTION
A number of radio systems that are designed to operate in shielded environments, such as mines and long tunnels, are known. One such system is disclosed in U.S. Pat. No. 4,972,505 to Isberg for “Tunnel Distributed Cable Antenna System With Signal Top Coupling Approximately Same Radiated Energy.” This system incorporates separate transmitting and receiving antennas and multiple signal taps to adjust the radiated energy.
Another system is described in U.S. Pat. No. 5,230,080 to Fabre et al. for “Ultra-High Frequency Communication Installation.” This system is intended for use at a site having multiple underground galleries. The system incorporates multiple repeaters which receive a signal which is retransmitted into the galleries over a combination of radiating and non-radiating cable sections.
A problem with known systems is that the systems require rather larger repeaters or in-line amplifiers, in order to ensure that a radio signal reaches all parts of the underground structure. Frequently, tuned resonant cavity networks have been employed to achieve the desired results, which are both costly and bulky. Additionally, such networks have high signal loss characteristics, which require larger, more powerful, and hence more expensive, amplifiers in order to operate. Such a system is also service intensive, in that frequent service is required in order to maintain the alignment and tuning of the system.
SUMMARY OF THE INVENTION
The antenna system of the invention is intended for multi-channel, two-way UHF underground communication includes a base radio station; a non-radiating coaxial cable attached to the transmit/receive connector on said base radio station; radiators affixed to said non-radiating coaxial cable at predetermined intervals along the length thereof, wherein said radiator is insulated from the center conductor of said coaxial cable; and bi-directional amplifiers spaced at predetermined intervals along the length of said coaxial cable.
An object of the invention is to provide an underground radio system which uses small, relatively inexpensive in-line amplifiers in an antenna system.
Another object of the invention is to provide an antenna system for an underground radio system which is inexpensive to build and easy to maintain.
Another object of the invention is to provide a bi-directional amplifier for use in an antenna system.
Yet another object of the invention is to provide a control radiation antenna, which will radiate RF energy and receive the same.
These and other objects and advantages of the invention will become more fully apparent as the description which follows is read in conjunction with the drawings.
REFERENCES:
patent: 3665480 (1972-05-01), Fassett
patent: 3673497 (1972-06-01), Thrasher
patent: 4777652 (1988-10-01), Stolarczyk
patent: 4849963 (1989-07-01), Kawano
patent: 4970722 (1990-11-01), Preschutti
patent: 5187803 (1993-02-01), Sohner
patent: 5230080 (1993-07-01), Fabre
patent: 5598097 (1997-01-01), Scholes
patent: 5809429 (1998-09-01), Knop
patent: 5966016 (1999-10-01), Suyama
patent: 6032020 (2000-02-01), Cook
Lee John J
Robert D. Varitz PC
Tunnel Radio of America, Inc.
Vo Nguyen T.
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