No, it is not but it is what most CBers are happy with and its quite cheap.
If you want to spent €120 and haul an almost 2m long antenna around, you also could use a Diamond RHM-8B, which is a telescopic amateur radio antenna. Tunable from 7 to 50MHz. Lenght is 177cm, retracted lenght is ~40cm. You will need an antenna tuner to get it tuned right. But be aware, the antenna rod is not flexible and if it gets catched in a tree it might break. Also an antenna rod this long will put a lot of mechanical force to the BNC connector of the radio when you move. This might induce damage to the housing and or pcb. However, performance will be better due to the lenght of the radiating element.
That is easily solved by a short length of coax and fixing the antenna independently from the radio - which is a good idea anyway, simply for the ease of use (antenna on the backpack, radio in the front where the hiker can actually reach it).
On the other hand, walking around with a 2m long whip, antenna tuner and what not - jeeze.
I wonder why the OP actually needs 11m CB - if it is to stay in contact with others on a hike, then something like a PMR walkie-talkie would be a lot more practical.