Citizen’s Band (CB) is technically dissimilar to FRS and GMRS (though legally in the same category).   FRS and GMRS are commonly walkie-talkies.   FRS walkie-talkies typically put out 1/10 or a 1/2 a watt.  Most GMRS walkie-talkies transmit 1 to 2 watts, with the more expensive one transmitting 5 watts.   FRS and GMRS users almost all use walkie-talkies rather than more powerful base stations and external antennas.  CB permits 5 watts, base stations and external antennas.   To get more range, having a higher antenna is more effective than solely focusing on transmitter power. 

FRS and GMRS are on a UHF band which is short-ranged.  CB is on a shortwave band, 26.965-27.405 mhz, which means the signal may skip.  The signal may pass over the more immediate area and bounce off the ionosphere enabling you to hear and talk to others who are further away but not hear and talk to those closer.  CB may not as good a choice for families to use in their neighborhoods or engaged in recreational activities for it is too powerful.  One using a CB for such close distances, will heard further away than intended and will tie up frequencies others could have otherwise used.  

FRS and GMRS transmit in FM.  The signal quality is more “natural” and similar to FM broadcast radio stations.  CB transmits in AM or sideband (SSB).  AM is a relatively inefficient use of both radio spectrum and of power.   SSB even more an efficient use of both radio spectrum and of power than FM.  However, some people find SSB hard to listen to. 

CB does not require a license so long as the CB radio is approved by the FCC and is not modified.  The FCC has no limits on mobile and walkie-talkie CB antennas.  There are limits on base antennas; no higher than 20 off the roof and no higher than a total of 60 feet off the ground. 

CB was popular in the 1970s due to movies such as “Smokey and the Bandit” and Songs like “Convoy.”  Truckers still use it today.  However, CB technology is vastly outdated for most of the CB radios sold today use designs from the 1970s.   These older designed means CB radios have receivers which are very vulnerable to adjacent channel interfere and overload; and often cause interference to other electrical devices. 

CB requires longer antennas which are ackward to carry and drive into parking structures with. 

What is more important is that CB often is a chaotic free-for-all with people intentionally transmitting on top of, if not deliberately jamming one another.  In the 1970s, less so today, CB’ers bought more powerful ham radios and amplifiers, some of them capable of 2,000 watts of power, and illegally had them modified to work on CB.  They did this because when they complied with the legal limit of 5 watts they were being intentionally transmitted over.   This is highly illegal for the FCC requires that each radio service uses only equipment its certifies for use on that band.  There also have been problems with false distress calls on CB. 

These days however, CB has fallen into disuse for the more sophisticated amateur radio service has decreased the requirements and standards of it licensing tests.  However, CB may be appropriate for those who do not have the technical aptitude to become a responsible radio amateur.  Note, if you buy a CB make sure it is a 40 channel one.  The 23 channel models were discontinued after 40 channels were authorized in 1977.  There are ads in the Recycler and on Craigslist selling 23 channel CBs as slightly used.