It could be that the "bnc" connector now has a bad connection internally from the radio being dropped, or? It could be that from connecting/disconnecting the antenna multiple times would cause a loose connection with the antenna to bnc. Or the operating frequency is not matched to the antenna so when you touch the antenna you're part of the antenna hence better reception. Do a search on antenna length to frequency match to better understand (if you haven't learned already). I always hated bnc connectors as the are prone to becoming loose or damaged over time. Good luck.