Sealing Antenna Connectors

Rayjk110 · Post by **Rayjk110** » Sat Jul 02, 2005 11:59 am

Hello. I know this may be a bit off topic on Motorola Radio Discussion, but I'm looking for any tips/hints any of you may have on how to seal Antenna Coaxial Connectors, particularly PL259 on RG8 Coax. Just some basic info on how to weather-proof it besides electrical tape.

Thanks in advance
Ray.

Post by **akardam** » Sat Jul 02, 2005 12:11 pm

I've had good success with non-adhesive silicone sealant. All my NMO mounts get a generous glop of it. So far, so good. :)

JohnWayne · Post by **JohnWayne** » Sat Jul 02, 2005 12:11 pm

There's a million different ways to do it, but this is the way I usually do it:

-First layer is 1/2" electrical tape inside-out so it doesn't stick to the coax/connectors and make a gooey mess when you want to remove it later.
-Second layer is butyl rubber; that thick gooey rubber stuff
-Third layer is 1" electrical tape
-Fourth layer is 1/2" electrical tape wrapped from bottom-to-top
-Fifth layer is 1/2" electrical tape wrapped from top-to-bottom; this creates a "shingle" effect to help keep out the water

This method applies when mating two sections together; either coax/connector to antenna or coax/connector another coax/connector. You don't usually take an individual connector and weaterproof it.

Let me know if you have any questions.

Jeff

Tom in D.C. · Post by **Tom in D.C.** » Sat Jul 02, 2005 12:17 pm

What you really need to know is that the trade name of the rubberlike sealant is CoaxSeal, and it comes in rolls of various widths. It's
available at hamfests, electronics stores, and I'll bet you can easily find someone online who sells it. The generic name for the stuff is "RTV' which stands for Room Temperature Vulcanizer. You put it on the connector sort of like you would tape, then you press it into place as you go along so that it seals up the gaps. Taking it off is not a bad job as long as the ambient temperature is not too high; if it is just wait a while until things cool off and then the RTV comes away clean from the connection point.

tvsjr · Post by **tvsjr** » Sat Jul 02, 2005 12:56 pm

I even have boxes and boxes of real Andrew vapor-seal (the nice, wide stuff that's so good for weatherproofing connectors, provided you underwrap it) that are available for sale. I probably still have 100 rolls around.

If anyone's interested, drop me a PM and we can chat.

EKLB · Post by **EKLB** » Sat Jul 02, 2005 1:07 pm

I use the electrical rubber insulated tape in 3/4 inch width then finish the outside with Black electrical taped wrapped so that the water runs over the wrap edges rather than into the wrap edges.

Done this for years with not one problem to date .

EKLB

Rayjk110 · Post by **Rayjk110** » Sat Jul 02, 2005 1:13 pm

Hello. I just came acrosssome stuff in my garage named "Blue RTV Silicone" Gasket Maker, 6B. I also came across another tube labeled Permatex Form A Gasket Sealant. Will any of these work in sealing my connector? (connector to antenna).

Thanks.

kb0nly · Post by **kb0nly** » Sat Jul 02, 2005 2:06 pm

Here is what i normally do. First of all when i install the PL-259, i don't bother doing the heatshrink with the clamp on "N" connectors since they are usually rather waterproof by design, i will use some heatshrink tubing that has the hot melt adhesive on the inside. When you shrink this down onto the coax and the back end of the PL-259 make sure you have the barrel threaded up onto the connector because some have a tight enough tolerance that they won't go over the heat shrink. This is also a benefit when up on a tower since the barrel of the connector can't slide down the coax if you spin it all the way loose from the connector body.

The heatshrink will seal up where the coax outer shield meets the connector. Then after that i will wrap the entire connector and whatever it is screwed onto with two layers of self vulcanizing rubber tape. Starting at the top down, then back to the top.

Then a couple layers of regular old black electricians tape since the self vulcanizing rubber is not UV resistant and would break down over time. I have been doing it like this for years with little trouble.

I have tried a bunch of these coax seal products, but its like having a big ball of bubble gum wrapped around the connector and messy. The self vulcanizing rubber makes a nice custom formed rubber boot around the connector and its easily removable. To remove it just take a razor or knife and cut it at the metal body of the connecter so you don't nick the coax and then just pull it off. It's really interesting because when you take it off, even after years of use, it will hold its shape and you can see an exact imprint of the connector and the threads of the mating connector on the inside surface. Great stuff!

kb0nly · Post by **kb0nly** » Sat Jul 02, 2005 2:08 pm

Rayjk110 wrote:Hello. I just came acrosssome stuff in my garage named "Blue RTV Silicone" Gasket Maker, 6B. I also came across another tube labeled Permatex Form A Gasket Sealant. Will any of these work in sealing my connector? (connector to antenna).

Thanks.

They will work, but its messy and not that easy to clean it all off if needed in the future! I came across one like that on the top of a tower one time, what a pain in butt, i must have spent an hour up there with a wire brush cleaning the crap off the antenna connector threads before putting it all back together.

Rayjk110 · Post by **Rayjk110** » Sat Jul 02, 2005 4:30 pm

Thanks for all the advice, guys. What I had ended up doing was putting some Blue RTV Silicone "Gasket Maker" on the female (antenna part of connection) threads, and then screwing the connector onto that. After that I applied 3 generous layers of electrical tape onto it. Keep in mind that this was a discone, and that the main coax connector was not exposed greatly to the elements as it was slid up into 1/2 Feet of metal tubing, but there was still the chance of moisture getting in. By the way, this is the antenna:

http://www.radioshack.com/product.asp?c ... d=20%2D043

I know it's RadioShack, (don't laugh) but it was given to me, so I can't
argue that one.

Thanks again for the help.
73

kb0nly · Post by **kb0nly** » Sat Jul 02, 2005 7:05 pm

Won't catch me laughing about a "free" antenna. Anything free is worth doing something with, LOL.

kf4sqb · Post by **kf4sqb** » Sat Jul 02, 2005 7:41 pm

Rayjk110 wrote:Thanks for all the advice, guys. What I had ended up doing was putting some Blue RTV Silicone "Gasket Maker" on the female (antenna part of connection) threads, and then screwing the connector onto that. After that I applied 3 generous layers of electrical tape onto it. Keep in mind that this was a discone, and that the main coax connector was not exposed greatly to the elements as it was slid up into 1/2 Feet of metal tubing, but there was still the chance of moisture getting in.

Well, that'll certainly work. The only thing I would've done differently would be a variation on what was suggested earlier. I would've assembled the connecter first, then wrapped it with electrical tape, sticky-side out, then coat it with the RTV. That way, it is well waterproofed, but will still come off clean later if needed.

The way I normally do this is with a layer of electrical tape (nothing but Scotch brand Super 33+ will do!) turned sticky-side out, then a layer or three of rubber tape (Scotch brand 130C linerless rubber splicing tape) that slightly overlaps the outer limits of the electrical tape, then a layer or three of electrical tape (Super 33+, of course) around the outside of everything, with the last layer wrapped from bottom to top for the "shingle effect" mentioned in JohnWayne's post, but he got mixed up and said top to bottom.

Sealing Antenna Connectors

Sealing Antenna Connectors

Sealing connectors...