The longer cable is helpful On one of mine its up in a tree ,
Under stand the cellular transmissions are a high frequency, short wave length type of signal, the do not adhere to the curvature of the earth.
That means, that for all practical purposes, cellular transmissions are line-of-sight signals. Having the ability to mount the antenna almost 15 ft higher than the camera can provide a huge boost to usable signal, simply because it has a better "view" of the cellular tower that it is pointed at.
This altitude gain can also compensate some amount of terrain blocking due to hills or valleys.
a gain of 8 is massive , in terms of better signal , good luck find a good area then get the antenna as high up as you can . that type of gain in strength is like 1.5-2 bars