My experience with the 396XT is that it is essentially deaf on CB frequencies. I went on a road trip and tried to pick up CH19 and couldn't get anything even with my 3ft telescoping antenna. Thought my scanner was broke, honestly, until I got home and tuned into my regular public safety frequencies. I'd be curious to see how it picks up 10 meter - probably just as bad (never tried).
I understand antenna plays a role, but you also have to understand that so many truckers are operating illegal rigs themselves and blasting out hundreds of watts sometimes. I have a $20 CB walkie-talkie with a crap antenna that can receive much better.