What’s The Difference Between Ham Radio and CB Radio?

	CB Radio	Ham Radio
Definition	CB radio, used in many countries, is a system allowing short-distance person-to-person bidirectional voice communication between individuals, using two way radios operating on 40 channels near 27 MHz (11 m) in the high frequency band.	ham radio, is the use of radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communication.
Licensed	CB operation does not require a license;	License needed;
Commercial	it may be used for business or personal communications.	The ham radio is used to specify "a duly authorised person interested in radioelectric practice with a purely personal aim and without pecuniary interest;
Power	Transmitter power is limited to 4 watts in the US and the EU.	handheld will transmit around 5 watts, mobile ham radios will operate around 25 watts.
Frequency allocations	CB radio is not a worldwide, standardized radio service. Each country decides if it wants to authorize such a radio service from its domestic frequency authorizations, and what its standards will be;	The International Telecommunication Union (ITU) governs the allocation of communications frequencies worldwide, with participation by each nation's communications regulation authority.
Frequency	40 channels, 26.965 MHz-27.405 MHz;	No channel limited; 144-148Mhz;420-450Mhz;222-225Mhz; 3Mhz-30Mhz shortwave HF band;

CB was the only practical two‑way radio system for the individual consumer, and served several subsets of users such as truck drivers, radio hobbyists, and those in need of short‑range radio communications, such as electricians, plumbers, and carpenters, who needed to communicate between job site and main office. While some users have moved on to other radio services, CB is still a popular hobby in many countries.

27 MHz is a relatively long wavelength for mobile communications, and the choice of antenna has a considerable impact on the performance of a CB radio. A common mobile antenna is a quarter-wave vertical whip. it is mounted low on the vehicle body, and often has a spring-and-ball mount to enhance its flexibility when scraping or striking overhead objects. Most all ham radio antennas are good to go from the factory and do not require tuning. and there are many ham radio antennas to choose for your HT ham radio or Mobile Radio.

CB runs on 27 MHz frequencies. Ham VHF and UHF runs on 147 MHz and 440 MHz respectively. The higher the frequencies, the easier it is for signals to punch through objects like trees, bushes, vehicles, etc. Even in different terrain, you will want to use either VHF or UHF for communications. Over deserts or flat land or water, UHF will work better and go further. Over mountains, and hills, VHF will work better.

the disadvantage of CB radio is that CB cant use repeater. but there have many amateur radio repeaters.