CB Antennas... unfortunately I can not put up an 18 foot CB antenna because I have no roof access, no antennas allowed, no garden or outdoor space to get one up either.
The only way is going out of the window with a mobile CB antenna which is a lot shorter but I will have no ground plane, even when I build a plane plane for it, I just don't know if I could make one good enough. A car body for example makes a good ground plane and becomes a big part of the antenna so much so that the car body adds gain and can give it the performance of a 5/8 wave 18 foot homebase antenna. I don't think my ground plane would come anywhere near to the performance of a car body...
The days of the CB mag mount on a biscuit tin are long gone and wont do anything in todays world as fewer people have them now. There is also a lot of noise on the band so people run power to be heard over the noise and also to improve range because 4 watts from an old CB will be very short range, you'd need at least 20 or more to be heard plus a power mic.
Cb radios were designed to be short range 1 to 2 miles, low modulation, often very poor and 4 watts. Back in the 80s/90s this was fine, you;d be heard because there was no noise on the band to get over and more people had them locally so 4 watts and low modulation was all you really needed to talk to your friend down the road and your other mates a few streets away.
These days people run 50 to 100 watts with power mics and 18 foot antennas mounted onto tall poles often on tower blocks, there is a lot of noise on the band so a good antenna is needed. Mobile whips work very well but thats only when they are on car bodies not hanging out of a window in a house so making a good ground plane is very important otherwise the signal could be very crappy.