Remember an antenna "talks" from the center of the 108" whip (high voltage at ends, high current in center)
There are several designs of helical antennas that work great, you can get them from 3' long to around 8' for CB band. What they do is take a piece of wire that is the correct length for the band, then wrap it around a fiberglass rod. As they get near the top the windings are much tighter, moving the center of the "antenna wire" closer to the top of the "antenna stick" They are called "top loaded"
Here is a clip from Firestick Top loaded (helical wire-wounds) antennas perform better than center loaded antennas, center loaded antennas perform better than base loaded antennas
There are several designs of helical antennas that work great, you can get them from 3' long to around 8' for CB band. What they do is take a piece of wire that is the correct length for the band, then wrap it around a fiberglass rod. As they get near the top the windings are much tighter, moving the center of the "antenna wire" closer to the top of the "antenna stick" They are called "top loaded"
Here is a clip from Firestick Top loaded (helical wire-wounds) antennas perform better than center loaded antennas, center loaded antennas perform better than base loaded antennas