A old style CB was a 27 mghz (high frequency) where as a UHF is 477 mghz (ultra high frequency)
The UHF has better audio quality but is only good for short distances (probably 30klm maximum unless you transmit through a repeater) ,a CB on AM might get you 10 klms where as with a CB on sideband might get you 30 klms but on sideband with skip running (the signal bouncing off the ionosphere) you could almost talk anywhere around the world (but it was a lottery who you would talk to) with a big enough aerial and fabourable conditions
CB's were originally 23 channel,then 18, & finally 40 (showing my age here) & in theory we needed a licence to operate them with a allocated call sign
Regards Don