minimising cb radio

[donkey]

My boss has a question that I cannot adequately answer.
Why can a mobile broadcast a few km to a tower and are so small but cb radio's have issues broadcasting 300metres indoors?

 

[KJ6EAD]

The longer wavelengths of CB are more readily attenuated by the building and the shorter wavelengths used for mobile phones penetrate the various spaces between attenuating materials better. The wavelength of CB is something like 37 times longer than mobile phone wavelengths, about like the diameter difference between a marble and a basketball.

There are other, not insignificant, but highly variable differences having to do with relative susceptibility to interference of AM analog (CB) and FM digital (mobile phone) transmission modes.

 

[davenn]

and also cell towers use hi gain antennas

which CB band were you referring to ? 27MHz or 477 MHz ?
even between those 2 there's quite a difference in comms abilities

Dave