Definition: The receiver antenna on an RC is often housed inside a flexible plastic antenna tube. The antenna cap is a small piece of rubber or plastic that goes on the end of the antenna tube to keep the antenna wire from sliding back down into the tube.
Antenna Cap Alternatives: A homemade antenna cap can be made from a tiny piece of plastic fuel tubing. A very small rubber band or a piece of tape can serve the same purpose -- holding the antenna wire in place -- however tape can attract dirt and needs replacing frequently.
Common Misspellings: antena cap
Examples:
Want to get fancy? You could paint the antenna cap or add tiny decorations and call it an RC antenna ball.