Licensed AM broadcast stations employing directional antenna systems are frequently faced with monitor point readings which exceed the limits specified on the station license. Correcting the problem is often time consuming and expensive due to conditions beyond the stations’ control. In September, 2008, the FCC released a Public Notice in MM Docket No. 93-177 which provides significant relief for AM stations by simplifying the process of verifying the proper operation of AM directional antenna systems. The process is based on the use of moment method computer modeling in conjunction with careful evaluation and certification of the internal monitoring system installed at the transmitter site.
Click Here to view the full document: “A Broadcast Engineer’s Guide: AM Directional Antenna Performance Verification Using Moment Method Modeling.” Note that this paper was written as a guide for licensed stations. A party wishing to license directional facilities for the first time will be required to certify radiator spacing and orientation as set forth in the rules.