AIS greatly reduced range

[Breaking Waves]

just as a note - pl259 connectors are simply not the best choice for this application. They are not inherently weathertight. If you have one. you should fill them with di-electric grease and wrap them with Self-amalgamating tape . . . . but type N is an inherently better choice for this external application - like here . . . . MD20N V-Tronix

type N is also better for any mast base connection - which can potentially be wet.

[continuouswave]

An exposed-to-the-weather UG-21 cable-end N-connector probably needs to taped over and protected, just as a UHF-series PL-259 cable end connector would be, to keep water from getting into the connector

In the case of a cable connector pointing upward to connect to an antenna base receptacle that is open and unprotected from water dripping down, both N-series and UHF-series cable-end plugs will likely need to be taped over to keep water from dripping into the connector at the mating face. In that regard, the UHF plugs are easier to tape over because the diameter difference from the socket to the plug is minimal and can be easily accommodated by the flexibility of Scotch 33 vinyl electrical tape.

A properly installed PL-259 connector will be threaded onto the vinyl jacket of the RG-213/U coaxial cable, which produces a well-sealed junction.

A properly installed UHF cable-end plug (PL-259) mated to a UHF socket (SO-238) and carefully wrapped with real Scotch 33 vinyl electrical tape will keep water out for a decade or longer, in my experience (which includes about 50-years of using UHF-series connectors outdoors to connect to antennas).

The principle advantage of the N-series over the UHF-series connectors is a more constant impedance through the connector, but at 150-MHz that difference is negligible and meaningless. The N-series cable-end connectors do have a rubber seal for the cable side of the connector, and a rubber base for the mating side of the connector, but I would not trust them to eliminate water intrusion, particularly in the cited instance of mating to a socket at the masthead which is likely to have water dripping down into the cable-end plug.

[mglonnro]

We had this same problem with our new Hanse (splitter included). For us it was an easy fix, the connection to the mast (VHF) cable wasn't properly tightened.

[Breaking Waves]

Originally Posted by continuouswave

An exposed-to-the-weather UG-21 cable-end N-connector probably needs to taped over and protected,

yes, agreed, no reason not to.


A properly installed PL-259 connector will be threaded onto the vinyl jacket of the RG-213/U coaxial cable, which produces a well-sealed junction.

A properly installed UHF cable-end plug (PL-259) mated to a UHF socket (SO-238) and carefully wrapped with real Scotch 33 vinyl electrical tape will keep water out for a decade or longer, in my experience (which includes about 50-years of using UHF-series connectors outdoors to connect to antennas).

stan honey was specifically involved in troubleshooting various anti-collision issues, including ais/vhf issues in the Volvo 65 fleet following a collision (report is also worth reading for other issues, like radar recommendations). His antenna conclusion (worth reading - covers much more than just the connector type)was that type N was superior to pl259 for this application. Given that his expertise is rather well-grounded I personally would tend to trust and follow his recommendation. If you think you know more about this than Stan, it is not worth arguing it.

.......

[CarinaPDX]

All too often we let the better be the enemy of the good. Either connector type will serve quite well; after all the PL-259 connectors are by for the most commonly used for marine antennas. While the PL-259 makes no pretense of being waterproof on its own even N-types can leak if not snugged up well. So whichever is used, always snug up firmly then seal properly. Again there are several adequate approaches that will serve, just be sure to do something that will seal and survive sunlight for potentially decades. 3M vinyl electrical tape is not adequate on its own for exposed applications. The old belt-and-braces approach of electrical tape/coax seal putty/self-amalgamating rubber tape (or perhaps a more modern rescue tape) is the gold standard, but not the only good answer. This is all much more important than the connector within.

BTW also check out the seal of the antenna's base coil - some may benefit by some attention. I had a high-performing Morad antenna that was sealed with o-rings, which was quite impressive. But the plastic tube around the coil was turning to powder in the sun so I put black heat shrink over it to protect it. It still works great but is just a spare these days.

Greg