I'm sure a lot of these truckers are using a "boot"(linear amplifier).
if you are pulling a trailer why not mount a full length 1/4 wave (9ft.?) whip antenna on the trailer?
if not,get a magnet mount antenna with the best DBD(decibels over a dipole) gain you can get.mount it on the roof.
if nothing but the best will do,buy a ham radio h.f.(or multi-band)--many are for sale cheap now.you need a license for a ham radio but a
modified(diode removed or software modded) radio will give more power and better receiver quality.legal transmit is 4 watts but ham radios do more--side band is 12 watts legal.
SWR(standing wave ratio) is important--get the antenna tuned.
CB transmits at the end of the shortwave spectrum(between 26-28 mhz.)