Even if the antenna says 1090 MHz, most of the time it’s not optimized for that frequency.
Almost all such antennas are falsely called 1090 MHz antennas.
For whip antennas, i haven’t encountered a case where the performance didn’t improve when cutting them to length:
How to improve performance of whip antenna of DVB-T
If you are using one of the nooelec antennas, those are very very bad. (unlikely with your range)