One of the major considerations in engineering a microwave route in the continental United States today is the selection of frequencies and hardware to permit the maximum utilization of the frequency spectrum in the most economical manner. In order to utilize the computer, the engineer must have a complete data base of existing frequency emitters and a thorough knowledge of propogation and the susceptibility of existing hardware to the proposed emitters. The procedures and computer programs to aid the engineer to properly frequency coordinate the proposed microwave facilities are discussed in this paper. The various types of emitters and the steps required for coordination are also covered.