I found an article a couple of weeks ago regarding air coil inductors for RFI feedback. I don't know what I did with it. The author had researched various coil designs including loose coils. His reseach indicated the best design was for twelve tightly wound coils of coax around a 4 1/2 inch PVC pipe. He had tested coils with varying numbers of wraps 12 was the optimum. I installed it to my base station vertical and it eliminated the feedback.
|