Most antenna’s will not have a perfect 50 ohm match and therefor they will return a (smaller or bigger) part of the signal back. This signal will usually also travel on the outside of the feeding coax back to the node. This will make the coax (and the node) radiate and so they will become part of the antenna, disturbing your theoretical radiation pattern. (The pattern may radiate more upward or downwards, leaving less power in the desired horizontal plane)
So comparing different antenna’s with different coax cable lenghts is tricky.
If you want to prevent the feedline and/or node from radiating and disturbing the antenna radiation pattern you should put a ferrite clamp-on over the coax, as close as possible or at 1/2 lambda (17cm) from the feedpoint of the antenna.
Ferrite clamp-on filters are available in many sizes , so you can easy find a size that will exact fit your coax feedline while it’s position on the cable stays fixed.