Recently, the US and Candian governments have approved CB Radios with FM mode for use in the United States, and Canada. Allowing for FM broadcast mode, will offer clearer, noise-free transmissions that were not possible using AM. FM has been popular in other countries and radio bands for many years.
New models of CB radios with FM mode are now available from Cobra, President, and Uniden, and can still be used with users of older AM only CB's.
The main advantage of AM mode is longer range, the advantage of FM is sound quality at close range. Having a dual mode radio allows the user to switch between the two types of channels to find and use the best system for their needs. The new dual mode radios are fully compatible with existing CB radio setups, so no new antennas are required.