How did you waterproof your external antenna?

Hi guys,

Untill a recent issue with water ingress, I had my antenna on the roof ridge, working well.

I riveted a 2" PVC pipe to the bottom of the antenna “post” (about 6" alu tube that the ant mounted into), I then ran the coax from the ant, through the PVC tube.
With the inline amp in the PVC tube, I then wrapped the amp and conectors in self-alagamating tape, with PTFE on the F-plug threads. I used hotglue to seal the join between the top of the PVC tube and the alu tube from the ant.

STILL the darn thing leaked, ran down the inside of the coax and corroded everything up to the TV-power inserter…

How do others do this - have I missed something?

BTW - I was hoping to use a “masthead amp in an external weatherproof box”, but I cant find one that’ll cover adsb freq’s…

The rationale for mounting the inline amp was to “keep it as close as possible to the amp”.

Considering the coax run is maybe 12ft (I’m looking to use WF100 coax) - am I just as well to mount the inline amp internally, in the attic the otherside of the wall from the ant?

F connectors are not great for bulkhead use in outdoor environments where you need to effectively encapsulate the gear. The only exceptions, of course, are things that have the F connector factory molded into the enclosure. Yes, you can use Gorilla glue, or RTV, or try to somehow make an O-Ring or gasket, but in the end, the F connector barrels are not made for this.

Hot glue is terrible for outdoor use, as it expands and contracts with the temperature, or any flexing of the joint will easily loosen it enough to let water and air through.

What type of inline amp do you use? What antenna?

If you are using a homebrew antenna built onto an F barrel, remember the center pin is NOT sealed. Therefore, water can get in around the dielectric at the antenna, go down the center, into the coax, ruining everything in it’s path.

If you are using an antenna with SO-239 body, same issue. Not completely watertight.

Actual weatherproof bulkhead connectors for N, SMA, or even UHF style are the best bet. A few more bucks, but you won’t be piping water into your rig.

I live in an apartment, and my entire installation (antenna, coax, amplifier etc) is indoors as our Building Management (equvalent to HOA) do not allow anyone to install an antenna on roof or on wall of the building.

I used to curse them, and felt I am unlucky, but now hearing cy80rg’s story, I feel that I am lucky, and restriction on outdoor installation is a blessing in disguise.

Make a drip loop in the cable before it enters the components downstream of the antenna, it’ll prevent water from running down the coax into the equipment.

I think I mentioned this in one of your other threads, but use a generous amount of silicone grease on the connectors. It is very effective at preventing water ingress.

Hi cy80rg,
Self amalgamating tape is great stuff and the idea of totally encapsulating your connectors may seem tempting but I have found in practice that condensation will naturally form in any installation. I suspect this happened in your case and the moisture got in there eventually with ever changing ambient conditions/cooling of connectors.Trouble is when condensation is in there, its damn hard to get it out when covered in a coccoon of self amagly. If you want to go the full way and insulate everything,or put everything in enclosures its a good idea to leave an ample size drain hole at the bottom.
A piece of 32mm drain pipe with 1 blank end stop drilled to size for cable entry and sealed at the top end & leaving the bottom cap off makes a good external in-line amplifier enclosure.

This is not picking on any one person, or anything in particular, but it seems that most likely the majority of contributors here have smart phones or phones with cameras at the least, and can at minimum take a picture of the setup and post pics with the question to give us a starting point…

I take your point k5ted , I Would like to oblige but the prospect of climbing up 30 ft to my w3dzz antenna balun which i have weather insulated in this way holding on to a borrowed ladder with one hand and my smart phone in the other doesnt seem to be too tempting at present.
METAR @ EGOW Wind 20 kt from the Northwest with gusts up to 33 kt, Broken clouds at a height of 800 ft, Cumulonimbus. heavy rain showers.
I take it that the OP has the very same issue.

To explain further,
A 6 inch offcut piece of 32mm or 40mm sink drain pipe with a heavy duty pvc cable shroud put over the top of it for a makeshift rain hat , the amplifier hangs inside the pipe vertically. All, that is required is to trim the cone of the shroud to suit the cable entry, the bottom end of the pipe is left open to free air. Zip tie the pipe containing the “weather sealed amp” to your mast.

Matching shrouds are inexpensive and available online or at a local industrial electrical wholesaler

autocad experts look away now ! :confused:

This would not work in the highlands of Scotland as the rain can go upwards there on occasions !

For the Scottish version, you could add another shroud to the bottom and make the cable exit point bigger to allow natural drainage.
I see from a previous post that cy80rg already has silicone grease on the shopping list.

I had leakage once which ruined an inline filter. Since then, I use dielectric grease on all threaded fittings. I also use “waterproof” RG6 fittings. Here’s a couple pics of my “waterproof” setup using PVC and CPVC. I only slip fit, but could glue it to really really make it waterproof.


Re pics of rig…

Yup, completely agree with you all… my bad :blush:

These posts arent made from my home PC, so I dont have access to my pics - will post when at home! :slight_smile:

As always, thanks for the input from you all - making progress!


Yes, one reason I couldnt show pics, as you inferred, is that my ants on ext mast as yours is! :wink:

Also, the way you’ve done yours is pretty much how I did mine, except I had one of these on the bottom - basically a pvc end cap…

For future ref, should I leave the bottom open, for drainage?

**Scrub that - just notcied the answer in your reply… :blush: **

I only use the cap on the bottom when it is free standing. When it is on the mast, it slip fits into the CPVC - PVC adapter. If you look at the 1090 COCO in the top picture, you can see where I have a hole drilled in the 90 degree bend for the cable to exit. That hole is slightly oversized to allow the connector to fit through and allow any moisture to drain/breathe out. The amp is directly below the 90 and has dielectric grease on the threads. That is where I originally had a high pass filter (diplexer). I have had no issues since switching connectors and adding grease.


Morning all,

I have a guy taking my external ant down tonight.

Idea is to replace the coax, waterproof everything, then put it up again.
I’ve got to do this quickly though, as the guy will be hanging around to put it back up again.

Currently, my “old” rig has the inline amp in a tube connected to the mast, with the ant on top, just like the diag above in this thread.
The plastic tube the amp is in is riveted to the mast.

Now I have a HabAmp indoors (attic) this makes the run a lot simpler, no need to cut the coax to insert the amp etc.

So, here’s what I’m thinking:

  1. Remove coax assembly
  2. Remove plastic pipe (drill rivets)
  3. Rebuild coax (Wf100 with compression F-plugs).
    3a. “Electric grease” (forget what it’s called) on the plugs.
    3b. Electric grease inside the f-connection (does this impact continuity?)
    3c. Self amalgamating tape round the F-joint, to say 2" up the coax
  4. The ant I have has three legs forming the ground plane. These screw into the base of the ant itself.
    4a. Electric grease on the threads of these legs
    4c. Hot glue around the leg insert points once in
  5. Zip ties to attach cable to mast
  6. Replace, leaving “drop loop” slack in cable

So, questions:

  1. Does “electric grease” (what is that darned stuff called? :wink: ) impact continiuity, or can I literally put it in the connection?
  2. “Drip loop” is there a better way to stop water running down the ext of the cable? (I’ll see what imapacts have the
  3. Anything else I can do to water proof this puppy?

THX :slight_smile:

(All being well, will report back on stats impacts later tonight).

Wow, that’s intense. I hope it works!

I’ve had 3 antennas on my roof: 1 homemade in PVC, the upgraded to FA 6db, and now the FA 8db. I’ve sealed all of the connections with the self amalgamating tape, pulled very very tightly such that none of the connectors were visible. The powered amp is up there too, same deal. Never had any water penetration. I’m in the northeast, so we have high wind, torrential rain, tall snow… the works.

That tape is great stuff. I wonder if the water could have gotten in from somewhere other than the connectors…

I just mounted mine last week with a similar setup and the first rain is today, so fingers crossed. A quick thought, if you sealed with the self-amalgamating silicone tape, it’s not UV resistant, so you should cover it with some UV resistant electrical tape, e.g. 3M 88, to make sure it lasts.