FCC Clarifies New AM Directional Proof Of Performance Option
October 30, 2009 at 4:33 AM (PT)
The FCC has clarified its new procedures for AM directional antenna performance verification using the "moment method" proof of performance after the optional procedure raised questions from engineers.
In its clarification, the Commission said that moment method modeling is permitted only for directional arrays with series-fed radiators and standard ground systems; top-loaded directional antennas are eligible only if fed in series. To use the moment method proof, a station must offer a post-construction surveyor’s certification to verify that the towers in its directional array have the proper spacing and orientation (with presently-licensed stations not changing their licensed facilities exempted from the certification rule); the Commission will allow a tolerance of 1.5 electrical degrees for the location of each tower in a directional array.
Other clarifications involve the measuring of tower impedance, antenna height adjustment within the model, statements of calibration, and filing fees and procedures.