I have tried various antennas instead of the original rubber duck. Most of them are from Diamond, Comet and Nagoya. All are dual band antennas because i am unable to fint any full size VHF antennas with a SMA connector. None of them seem to outperform the original shortened antenna. What i am looking for is good performance on 2m, if it works OK at the marine VHF band that is a bonus. Any suggestions?