Found out I was terminating F connectors wrong for 6 months, all because a customer in Boise asked me why her picture cut out when it rained | Cable Installers - Hub Chatter
Check the braid isn't touching the center pin when you crimp. That tiny strand of shield hair is what shorts out when moisture gets in. Also make sure your stripper isn't nicking the copper, a small cut turns into corrosion fast once it rains.