Waterproofing a Metz Manta antenna

[CptPat]

Originally Posted by BogMonster

The new RIB raider on the Vipermax does not seem to work properly - something wrong with the connection in the bottom I think as it does not seem to screw in properly (the first one got broken in the UK, that one screws right onto the coax fitting fine, but the replacement does not).

So I thought I would bite the bullet and get a Metz Manta as they seem to be well thought of.

Problem I have is that the bottom of the antenna is not waterproof for use on an A frame installation.

Photo of the antenna is here: Salty John: Metz Manta Marine VHF Antenna plus Metz AIS antenna and other fine boat and yacht chandlery products.

The fat part of the base has an O ring (you can see it in the photo) so would seal onto the top of the plate on the A frame OK, but the fitting into the bottom is just a double ended SO259 connector which screws into a hole in the base of the antenna. Normally I use PTFE tape to waterproof threads but obviously that's no good on an antenna because it will insulate the connection ... likewise I'm not really keen on using sealant for the same reason.

Any thoughts on the best way to waterproof this properly? The plug onto the SO259 is no problem because I got a roll of the Bandit tape with the aerial so will wrap that up as directed, but it's not at all waterproof where it screws into the bottom of the antenna. The best idea I can come up with is to just squidge a load of silicone sealant around the base when assembling it onto the A frame but I'm not that convinced by that.

A separate problem is that the antenna is secured by a nut on the barrel of the SO259 connector. The antenna plate on the A frame is much thicker than the normal mounting bracket and in order to get the nut to engage on the threads I have to back the SO259 out so far there are only a couple of turns of thread still left in the antenna base, I haven't figured out how to sort this yet, what I really need is a double ended SO259 that is threaded all the way down the barrel but I haven't found one locally yet.

Does anybody see any problem with cutting the plug off the end of the RIB Raider antenna and using the same coax? I'd rather not run a new coax because it looks like being a PITA due to the amount of other stuff in the trunking...

Go to Home Depot and in the electrical department find heat shrink tubing made by Raychem of the proper inside diameter to cover the PL-259 connector and socket. Cut the tubing at least long enough to cover the connectors and at least 2 inches of coax cable. With a heat gun, being careful not to overheat the cable, shrink the tubing over the connectors to waterproof them. To remove later, cut the tubing (carefully) with a utility knife to split it and it will peel it away.

When heated, the tubing not only shrinks but also coats everything with a waterproofing heat-activated plastic.

The other option is to go to Ham Radio Outlet and buy a roll of mastic tape that has the consistency of tar and is intended for water proofing connectors. It is less durable than the heat shrink tubing, but more flexible.

[AMac]

Put it together make sure it's working correctly and spray with a product called Darrathene, not sure of spelling I'll check today, it's fantastic for waterproofing electrical connections.
I've been using it for years.

[Ovey]

Hiya,

Darathene (Certified Labs) is a good friend of electronic engineers, but I've only ever used it (and seen it used by others) in less exposed areas such as in airlocks leading to the upper deck on big ships, etc. - areas that get damp but not wet.

For outside use (in direct sea/salt spray and areas of heavy water hits) I would recommend cleaning the connector and the cable, ensuring a good connection (test it to make sure) and then sealing it with self-amalgamating tape. Work from "down" to "up" so that the overlaps cause water to run down off it, not down into it. You could maybe even go over the top of the S-A tape with Denso-tape (which is sticky and horrible so be very careful how you put it on if you decide to use it)!

[ashbypower]

Originally Posted by CptPat

Go to Home Depot and in the electrical department find heat shrink tubing
The other option is to go to Ham Radio Outlet .

As the OP is in the Falkland islands, I would guess its not that straight forward, and after 4 years probably has it sorted anyway.

[Ovey]

Hmm, good point! I just added to the most recent posts without looking at the OP! D'Oh!