We have a firestik no ground plane antenna on the curbside of the roof on our 2900 PC. It tuned great. It is 13.5" tall with a special 15' no ground plane cable.
The CB is the Cobra all in one. Speaker and all controls are in the handset so very little space is taken for the CB.
We also have a Wilson Cell phone amplifier with a Wilson short antenna on the street side of the roof to enhance our cell phone reception.