Here is a link to a fitting I found. Quite pricy but I think it will work well. This is just one of many sources of the item offered by NewMar. It is actually made in England, but I can not find the source.
http://www.yachtsupplydepot.com/elec...prod_9493.html
There are several models for single and multiple wires depending on your requirements. It makes it nice to be able to seal coax and retain the PL connector on the end. This is a marine devise and should give a real good weather seal.
I ordered a DX-3 paid around $33.00 and will use it to bring my wiring in through the roof from the antenna to the radio. I will show pictures of the install when I finish.
Other models are CCX-R, CCX-S and CCX-T. A Google search of any will bring up numerous sources of supply.
JIM