Just one more comment on this topic:
Ron addressed marine use. My former job of 15-years was working as
lead electronic tech for an oil spill recovery organization whose
primary region of operation is Cook Inlet in southcentral Alaska (200
by 30 mile body of salt water). Electronics installed on boats
ranging from 25-foot to 210-foot provided an excellent outdoor
"laboratory" for testing cables and connections. Anything exposed
would corrode within three years. I sealed coax connectors of all
types by using a gray annealing tape from 3M (Scotch 30, I believe)
which was covered with a double wrap of Scotch-33+. Not all
electrical tape is the same and the 33 has more stretch in cold
wx. Cheap electric tape would get brittle and either break or
crack. I also used heat-shrink on some coax connections. Both
provided excellent service in a 100% humidity salt-water
atmosphere. I unwrapped some after 5-years service and were still
bright and clean.
DC wiring is more problematic when it typically ties to terminal
strips. Some experimentation with paint-on coatings worked but not
universally used as DC wiring needs to remain removable for
servicing. Some marine radios and radars provide rubber boots over
connectors. They were of marginal success. Keeps direct spray off
but not sealing from salt vapor. Most marine electronics has greatly
improved connections so that they are molded multi-pin design and
water-tight these days. Lots of gaskets used in marine electronic
cabinetry/enclosures.
I prefer to use N connections on VHF and higher frequencies as they
self-seal to an extent using an internal gasket. But always seal
over, as described above, as well. I have over 20 N-connectors in my
2m-eme system, alone. I primarily use LMR cable from Times Microwave
(and some RG-213 and Heliax). RG-58, RG-8/x, and LMR-240 is used
with BNC or N connectors mostly for short jumpers. UHF connectors
are used on equipment having those style connectors, since adapters
typically add some loss and unreliability. It pays to buy quality
for adapters; cheap ones have SWR and high insertion losses. You get
what you pay for (generally).
Hardline connectors, properly sealed, last for over a decade.
73, Ed - KL7UW
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