Most FM transmitters produce harmonics at even multiples of your fundamental frequency. If your harmonics fall on or near a TV channel or Maritime frequency you could cause severe interference to that channel.The most common cause of fines from federal agencies is due to TVI or other interference from your transmitter which generates a complaint.Use of a lowpass filter is an excellent way of eliminating this kind of interference since no tuning of the filter is required.
Since the insertion loss of these filters are less than 0.01 db, these filters are well suited for use on power levels as low as 100 milliwatts on up to 300 watts. All 3 units include a full 2 year warranty!