If the antena wire looks frayed, like maybe the strands of wire inside are breaking or might break soon; then I go to the hobby shop and purchase antena wire and replace it. It should always be 39 inches long. Never cut it short. Replacing the wire requires opening the reciever case and un-soildering the old wire and soildering on the new wire. Because the reciever circuit board is very crowded with other compnents a heat sink must be used to avoid damaging any other parts. You must be fast to avoid heat from building in the board, but you want a good soilder joint at the same time. If you haven't soildered much, you may want to find someone with more experience. It takes two minutes. Most antenas will get kinked or damaged at sometime or just worn from flapping in the breeze. I consider replacing the antena regular maintenance and do so about every 6 or 7 years.