ABSTRACT
This chapter discusses techniques and rules used for United States frequency coordination of the Broadcast Auxiliary Service (BAS). It provides an overview of the different ways frequency coordination is employed in an attempt to mitigate the effects of spectrum crowding on these essential auxiliary services. The chapter provides information about frequency coordination services, whether those services are provided by a local frequency coordination committee, a volunteer appointed by a local chapter of the Society of Broadcast Engineers or a commercial firm in the business of providing frequency search services. Under the prior coordination notice process, one first identifies all existing co-channel and adjacent-channel links sufficiently close to the proposed link to require study. When looking for potential to-be-interfered with paths, beware of special cases, such as split-path links. The Federal Communications Commission rules require all fixed-link BAS stations to use directional antennas. The chapter shows how parallel-polarized and cross-polarized signals between two fixed-link paths combine.
