joinng coaxial

[MarkGrubb]

it looks to me like we're caught between a rock and a hard place when trying to join coax.

If the joints are soldered, then as some have correctly pointed out there will be an impedance mismatch and that will result in loss of signal (both transmit and receive).

If inline connectors are used then these will be affected by the marine environment and corrode or develop 'green stuff', and the resulting poor connection will result in loss of signal (both transmit and received). I have no experience of this and use an inline connector on my boat without trouble, but I guess others haven't been so lucky.

So if you can replace the cable then do.

 

[MM5AHO]

Its virtually impossible to solder coax and maintain the impedance.
Coax cable is not like 12V DC cable where just making the connection counts, its radio frequency powder thats being transmitted and it acts quite differently to 12V DC.

Using connectors is the only way short of replacing the whole coax, but what type of connectors. BNC or N Type do maintain the impedance even at VHF, whereas PL259 / SO239 types are a poor match at VHF.

If connectors are used, its possible to seal the joint with self amalgamating tape (not "self annealing", annealing is a process of heat treating steel). Tape the whole connector joint and onto the coax a few cm for a good seal.