Hi Andy, this just proves a point that a lot of us SWLs, hams etc., have learned over the years, get the top end as sealed as water-tight as possible, don't worry about the bottom end, if open to air, water drains and air can dry (I live within 100 metres of the sea, about 200' asl, facing sw gales/storms coming in off the Atlantic) - just need to be wary of salty air which can corrode solder, aluminium and plays hell with dissimilar metals. Have a look on the 'net and buy a couple of tubes of silcone grease, lag connectors with it. Water will percolate through co-ax, and even move upwards through capillary action if it can get into it. The top of plastic drinks bottle can be placed over a connector and keeps it dry - doesn't look pretty or expensive, but works well!