Ultrashort electromagnetic waves VI — Reception

Mr. Trevor deals with the reception of ultrashort electromagnetic waves over line-of-sight paths under practical conditions. He shows that, when directive antennas are employed, there is an optimum antenna height for which the direct and reflected rays are received in phase producing maximum effect. The concept of excess-noise ratio is developed which evaluates the merit of a receiver in a manner independent of band width, receiver impedance, signal-generator impedance, or frequency. This is the concluding article in a series of six on ultrashort electromagnetic waves. The material contained in these articles was originally presented as a series of lectures before the basic science group of the New York Section at Columbia University. A consolidated reprint will be available (see announcement elsewhere in this issue). PAUL C. CROMWELL, Chairman, Symposium Committee (College of Engineering, New York University, New York 53, N. Y.)