Your receiver antenna wire is a finely tuned part of the radio system. To keep your radio at peak performance and to maintain proper range, never cut the wire shorter. You can wrap it around a piece of lexan to take up the slack, but don’t wrap it over itself as this can cause glitching and loss of range.
Also, never wrap the excess hanging out of your antenna tube around the tube as this will cause problems too. A few small pieces of fuel line will hold it tight against the tube so you can run it straight down the tube and keep it from flapping in the breeze. For more permanent set-ups, heat shrink tubing works great and provides additional protection during crashes.