Take this with a grain of salt, your mileage may vary, but I was trained as a sonar/radio technician in the military.

*looks at his iCOM portable VHF Radio..... hmmmmm

The antenna is a "rubber-ducky" type antenna. Inside underneath the roubber coating, is a very long insulated wire (sound familiar?) that is coiled around a central whip. It's range, however, is slightly less than when I use an external metal whip antenna. Why? While you are not changing the electrical length of the antenna when you coil it, you are altering its exposure to the RF. For best range the antenna should be full length in order that the full wavelength of a radio wave is expose "seen" by the antenna. A coiled antenna doesn't "see" as much of the radio signal so its range will be slightly less. My 4watt vhf radion can pull a repeater tower up from 50 miles away, so I do mean slightly.

When you cut an antenna you alter its electrical length, this "detunes" the antenna and causes the antenna to have a different natural frequency than the radio signals it receives which causes it to reflect the signal. It has a lot to do with impedence matching and such.

So.... cutting an antenna = "very bad!!" while coiling an antenna may reduce the range a bit, but I don't think it would change it to the point where you could still see the model at the time the change became noticeable.

That being said, I wouldn't coil the antenna unless I absolutely had to to prevent it from being caught in propellors or rotors.

Cheers,