Amateur radio equipment fundamentals / Alfred D. Helfrick. Helfrick, Albert D. Radio Equipment and supplies Design and construction Amateurs' manuals. Amateur radio stations. TK9956 .H392 621.38413 19 HEA Includes index. Englewood Cliffs, N.J. : Prentice-Hall, c1982. c1982. 1982 Text xii, 284 p. : eng