Whip aerial...or any aerial. Have you ever 'stretched sprue'?
Not sure what it's called now, I always knew it as the sprue - it's the carrier that the parts you are using are cut from.
Take a length about 6" long. Hold both ends in your hands (one in each!!) and gently heat it over a flame/heat source eg. gas or electric hob, for a couple of seconds and, when you can see it start to droop, take it away from the heat source and slowly stretch it by moving your hands apart. Get it to the thickness you want and stop - it cools very quickly so practice a few times. Usually the 6" length of sprue has doubled in length and gives you a thin line of plastic that can be used as aerial wire, handles, cables etc. Secure in place at the end of building with a dab of super glue or resin.
Grey plastic is good as it looks the right colour.
Don't try this at home, children, WITHOUT adult supervision........'Matches, matches never touch....they can hurt you very much!'