Science: Radio Ride

Surging through the giant turbines of Boulder Dam, the Colorado River can now produce 1,240,000,000 kilowatt hours of electric energy per year which is piped 267 miles to Los Angeles over six hollow copper cables 11 in. in diameter. In an engineering enterprise of this magnitude unique solutions of special problems are likely to occur. One such solution publicized in Los Angeles last week was the way in which radio communication is maintained with the 14 repair crews which patrol the transmission line in automobiles.

No ordinary low-power, short-wave radio set could conceivably be depended upon to carry 100 miles or more through the air. Possibly inspired by American Telephone & Telegraph Co.’s coaxial cable which can carry a frequency band wide enough for television for thousands of miles (TIME, Oct. 14, 1935), the Los Angeles engineers installed, at each end of the line, low-power transmitters using about 80,000 kilocycles, and these high frequency signals are impressed on the electric power cables. Through this broad channel they ride easily so that messages are clearly heard by any patrol car, provided it is within a half mile of the line. The great power flow of 275,000 volts so smooth that the radio signals riding piggyback are not distorted at all.