On Thursday, June 10, 2010 at 2:55:22 PM UTC-5, Twitchell wrote:
I've seen some car radio whip antennas that look like they have a wire wrapped
around them. The wraps are not close but lazily spiral down the length of the
antenna.

Does this help reception? Is the coil attached somehow to the car or just the
antenna itself?

twitch

The helical spiral on modern antennas serves nothing more than to break up vortices created as air passes around the antenna. Also know as vortex induced vibration. Keeps the antenna from whipping. If you notice in the winter time when your car antenna gets ice on it, it starts to whip more violently. You see the same things on larger cylindrical structures and poles like smoke stacks and wind turbine towers.