There is a section in your settings where you choose what Service Types you want to monitor. Be sure the appropriate Service Types are checked, as well as the Downloads/Monitor menu so that the scanner will load and monitor that list. Separate antennas are not required, but a better antenna is always recommended for good reception.
It is worth noting that the factory antenna will be very, very poor for picking up any CB.
I already bought the upgraded antenna. Works great.
The Remtronix one.Which one? For CB?
Remtronix is for 800mhz, CB is 27mhz. Extremely unlikely one antenna will cover both well.
Jonwienke posted this analysis before, comparing the Remtronix 800 VS the Diamond RH77CA. Lower is better. Dark is Remtronix, light is Diamond. Needless to say... it will be dreadful and near useless on CB unless a truck parks outside your window, perhaps.
If you want to listen to CB, use a CB antenna. It may be more proactive to get a CB setup that does channel scanning and use the SDS100 for other things, but, use it how you please.
There was another topic on scanning CB with an SDS100 in this section recently if you search it.