Taking your race car outside the oval tracks and getting on a road course? Since the average road course is over 2 miles long with changing elevations and line of sight, external antennas are needed to boost that signal to and from your car. Each radio can be outfitted with an antenna adapter that replaces the rubber flexible antenna that is currently on the radio. 15FT of RG-58A/U dual shield cable with 3/4" nmo base mount with BNC connector installed.