Drilling Holes in Roof for Antennas

[rbmartiniv]

This is a two-part question.

First, I would like to exchange the CB antenna that came on my '07 Fleetwood Discovery MH for a better one. Do I have to change the cable also, or does it just unscrew and a new one screws on? Sorry, to sound so simple-minded.

Secondly, I would like to add an outside WiFi wireless repeater for which I will have to run a power cable to a power source. I have heard that some people took it down through the topmost fridge vent (close to the passenger-side door on my MH). I saw where someone actually ran it down the waste tank vent (ugh!).

I would rather it be a little more permanent and "aesthetically pleasing" than either of those two possibilities. However, I am afraid to drill a hole in my roof without knowing more about what is involved. And once I have the hole, how do I access it from the inside (obviously I am not going to drill all the way through the ceiling)?

I would appreciate any suggestions, thoughts, ideas, etc.

Thanks a lot,

Robert Martin

07 Fleetwood Discovery 40X

08 Vue

[tbutler]

Years ago I put a booster for cell service on the roof. I chose a cabinet in front over the drivers seat. I drilled a small pilot hole through the ceiling up through the roof. Then I drilled the size hole needed from above all the way into the ceiling inside the cabinet. The roof opening was thoroughly sealed with caulk recommended by our manufacturer. The inside hole was covered with the washer that came with the antenna. I never had a problem with it. Several years later I removed the cell booster as it seemed to make little to no difference. I ran a second line from a new KVH dish/dome to feed to the rear TV so we could watch different channels on the two televisions. Again, sealed above with recommended caulk. No problems. If I were building RV's I'd install a dummy hole or two through the roof for user applications at a later date. No such thing as too many holes in a roof!

The caution is that when drilling a hole through the roof, you have no idea where wires, 12V, 120V or control wires of some kind might be run. I just took a blind shot figuring that there are only so many wires in the roof and I would chance it that I wouldn't hit one.

[chucknewman]

Robert,

I've drilled several holes in the roof, and recently one 4" hole in the side of the coach for a dryer vent. If you can see bare fiberglass of the end cap as I can in the front of our coach, go ahead and drill the size hole you want for antennas, spotlights, etc.

But when you want to safely go through the ceiling (or wall) consisting of one or more layers of fabric, wallpaper, cover board, foam insulation, and roof material do the following:

1. Determine where you want to run the cable through the ceiling (or wall) to the exterior. Check the exterior at that point for mounted obstructions.

2. If all looks OK, use a hole saw bit for the size hole required attached to a drill, and carefully drill the ceiling fabric and backing (or other coating) until you see bits of insulation. This will usually happen about 1/8" to 1/4" into the cut. Then stop.

3. Take a screwdriver and carefully clean out the insulation all the way to the solid cover on the roof. This could be anything from 2" to 5" of insulation. Just slowly spin the screwdriver and the insulation will fall out. The point of this is if you encounter wires you will not damage them and in most cases still can use the new hole for your cable. I've done exactly that. If you encounter a wood or metal brace (as I have) you can start a new hole. Do not drill through the support structure (beams) of the coach.

4. When the hole is cleaned out, you have two options:

A. Continue drilling in the same inside to outside direction with the hole saw through the solid roof material.

B. Drill a small pilot hole from inside to outside. Then go onto the roof and drill down with the hole saw using the pilot hole you just made.

5. Hole is done with no damage.

The point of "B" above is when you need a cosmetically clean edged hole on the outside. Drilling all the way through a wall or ceiling will cause some level of splintering or otherwise a rough surface around the hole exterior. Not generally important for a hole in the roof that will be covered with Dicor sealant or Silicone sealant, but important when drilling a hole all the way through the wall.

I don't understand your comment "...(obviously I am not going to drill all the way through the ceiling)?"

If you want to run a wire or cable through a wall or ceiling, then that is exactly what you need to do.

Regarding the CB antenna, even though my coach is mostly aircraft aluminum it does not make a good ground plane. Add the fact that the end caps are fiberglass and you have no good ground plane at all for the antenna. Most RV manufacturers use the wrong antenna on fiberglass bodies because they don't know and/or care. They know you will get some communication as long as the distance is close.

For that reason I purchased a Firestik (Firestik.com) no-ground CB antenna designed to work on non-metal surfaces. Note that the attached coax cable is part of the tuned antenna system and must not be cut or modified in any way. Note also that it will give you a little better coverage but it is questionable, in my opinion, for the cost and labor involved to remove the old one and install the new antenna. Unless you're using a higher powered radio.

Chuck