E. F. Johnson Company Catalog. Clearchannel LTR Trunked Radio 1985. Material: paper. Size: 8 1/2" x 11". Description: blue cover; color photograph of traffic jam; white print: "E.F. Johnson Clears the Air about Trunked Radio, What trunked radio is, how it works, and why E.F. Johnson's Clearchannel LTR with distributed logic is the logical choice"; E.F. Johnson logo; 4 pages. Logo in use from 1986-1993.