Effect CF Power Lines on AM Radio Broadcast Radiation Patteins

A power transmission line can create distortion of the radiation pattern of a nearby AM radio broadcast antenna array. Techniques have been developed to study this effect and remedial measures are proposed to minimize it. Three types of tower stubs have been tested. These consist of lengths of wire connected to the tower near the top and terminated near ground with capacitors that are tuned to the desired frequency. The effectiveness varies with the complexity of the stub. Two types of skywire stubs were also tested. These were difficult to tune, difficult to test and perhaps not as effective as tower stubs. Isolating the skywire fran transmission towers remains the least expensive but least predictable remedial measure. A systematic masurement technique for verifying the effects of remedial measures is presented.