Mounting a cellular antenna on the roof

[tetranz]

Hi all

I'm not quite sure what forum to put this in. It's related to mounting a cellular antenna but it's not a technology question. Sorry if this is a bit of a long ramble.

New RVer here with a 2017 Minnie Winnie 31K. Among the many tasks we need to do before setting off with some cats is setting up good cellular data. I'm quite competent about the technical side of this but the thought of mounting an antenna and getting the cables in etc is almost keeping me awake at night. It's not the sort of thing I want to make a mess of and obviously want to drill the minimum number of holes.

I'd appreciate any comments and general sanity check on what I'm planning.

I have one of these Poynting "shark fin" type MIMO antennas that I want to mount on the roof. https://poynting.tech/antennas-and-a...nas/mimo-3-15/

Ideally, for performance, it needs to sit on a metal surface. With a fiberglass roof, this obviously means some sort of metal plate. According the manufacturer's instructions, the metal needs to be a minimum of 400 x 400 mm or about 16 x 16 in. Opinions vary on the necessity of it. It might not make a huge difference but, knowing what I do about antennas etc from being into ham radio, I'd like to provide that if I possibly can.

I've looked long and hard to find a good position. I think near the back on the left (i.e., not the ladder side) a couple of feet diagonally in from the corner. There's nothing else there, it's far away from the interfering A/C unit etc and I have a convenient DC power outlet for the router in the bedroom below.

It can mount two ways. One way is to have it sit over a central hole. It has a plastic spigot that goes through the hole with a nut on the inside. The cable goes vertically down through the spigot. I don't think I can realistically use this method. I don't want to have to deal with the space between the ceiling and the roof so any hole needs to come down into a cupboard.

The other way is to mount it on a flat surface with no hole. The cable goes horizontally out the back. Here's my plan. Please tell me of I'm suggesting something crazy here.

I get a sheet of galvanized steel. Probably this: https://www.amazon.com/M-D-Building-.../dp/B000IKM1Y0 It's 28 gauge or 1/64 inch thick which is thin enough to cut with tin snips. I'd cut it to 16 x 16 or maybe a little bigger. I would stick it down with 3M VHB.

The antenna has a magnetic mount option. They're six little "buttons" which are strong magnets. I'd use that to hold the antenna on the plate.

For the cable, I would drill a hole down into one of the cupboards at the back above the bed. I would follow what I saw in a video which is to mount a plastic box over a hole and have holes in the side of the box for a cable to go in and then down. That will give me the future opportunity to pass other cables in through the box without more holes in the roof.

Does that sound doable? I don't know how strong the VHB is and if it is likely to damage the roof. The antenna is quite light and when mounted pointing forward, it doesn't have much wind resistance.

Maybe a silly question. The salesperson mentioned the word "rubber" when talking about the roof but it is fiberglass isn't it?

Thanks

[Phil G.]

Originally Posted by tetranz

Hi all

I'm not quite sure what forum to put this in. It's related to mounting a cellular antenna but it's not a technology question. Sorry if this is a bit of a long ramble.

New RVer here with a 2017 Minnie Winnie 31K. Among the many tasks we need to do before setting off with some cats is setting up good cellular data. I'm quite competent about the technical side of this but the thought of mounting an antenna and getting the cables in etc is almost keeping me awake at night. It's not the sort of thing I want to make a mess of and obviously want to drill the minimum number of holes.

I'd appreciate any comments and general sanity check on what I'm planning.

I have one of these Poynting "shark fin" type MIMO antennas that I want to mount on the roof. https://poynting.tech/antennas-and-a...nas/mimo-3-15/

Ideally, for performance, it needs to sit on a metal surface. With a fiberglass roof, this obviously means some sort of metal plate. According the manufacturer's instructions, the metal needs to be a minimum of 400 x 400 mm or about 16 x 16 in. Opinions vary on the necessity of it. It might not make a huge difference but, knowing what I do about antennas etc from being into ham radio, I'd like to provide that if I possibly can.

I've looked long and hard to find a good position. I think near the back on the left (i.e., not the ladder side) a couple of feet diagonally in from the corner. There's nothing else there, it's far away from the interfering A/C unit etc and I have a convenient DC power outlet for the router in the bedroom below.

It can mount two ways. One way is to have it sit over a central hole. It has a plastic spigot that goes through the hole with a nut on the inside. The cable goes vertically down through the spigot. I don't think I can realistically use this method. I don't want to have to deal with the space between the ceiling and the roof so any hole needs to come down into a cupboard.

The other way is to mount it on a flat surface with no hole. The cable goes horizontally out the back. Here's my plan. Please tell me of I'm suggesting something crazy here.

I get a sheet of galvanized steel. Probably this: https://www.amazon.com/M-D-Building-.../dp/B000IKM1Y0 It's 28 gauge or 1/64 inch thick which is thin enough to cut with tin snips. I'd cut it to 16 x 16 or maybe a little bigger. I would stick it down with 3M VHB.

The antenna has a magnetic mount option. They're six little "buttons" which are strong magnets. I'd use that to hold the antenna on the plate.

For the cable, I would drill a hole down into one of the cupboards at the back above the bed. I would follow what I saw in a video which is to mount a plastic box over a hole and have holes in the side of the box for a cable to go in and then down. That will give me the future opportunity to pass other cables in through the box without more holes in the roof.

Does that sound doable? I don't know how strong the VHB is and if it is likely to damage the roof. The antenna is quite light and when mounted pointing forward, it doesn't have much wind resistance.

Maybe a silly question. The salesperson mentioned the word "rubber" when talking about the roof but it is fiberglass isn't it?

Thanks

I mounted my RV cellular antenna right onto the top handle of the roof ladder that came stock on the back of our motorhome. I ran the coaxial cable for it across the roof and down the refrigerator vent on the roof. I held the coaxial cable down on the roof surface using 3 inch wide Eternabond tape.

I didn't want to drill any holes into the roof or exterior walls. However, our roof is fiberglass, so the Eternabond tape works very well to hold the cable down and will last for years and years.

[creativepart]

Your plan sounds very workable.

You might find some other pre-existing holes that would work, as well.

Some folks have run cables down besides an existing vent pipe. Lots of times in the back of a bathroom cabinet there will be a vent pipe running from the sink up to the roof for a plumbing vent. That gives you a chance to get the cable inside the RV easily and then go from the interior of that cabinet into an adjacent cabinet through a hole you'd drill in a wall. Lot's of RV cabinets in one room line up with cabinets in an adjacent room.

We had a class C once and I installed my cellular booster ant into the interior via the TV antenna hole. it was easy to remove the caulking around the King Jack antenna and run my wires and then reinstall the Antenna over the new cable.

On my current Class A, I have both a cell booster ant and a WiFi Ranger "booster" antenna (it's really an antenna with a wifi router that pairs with the indor router - it's not really a booster) on my roof.

I made the cabinets above the dashboard into my Tech cabinet and it was easy to drill through the fiberglass cap because there isn't any roof structure there. But most Class C MH don't have that option.

For a ground plane I bought a round steel "pizza pan separator" from amazon. It's a 12" round metal disk but they make them for bigger pizza's too, if you know what I mean.

Here's an 18" one, no cutting required:
https://www.amazon.com/American-Meta...dp/B003DAV41I/

I used simple NuFlex silicone caulking to hold down the pizza pan to the roof. It's not gone anywhere in 3 years. My magnet antenna sticks perfectly to the pan.

[tetranz]

Thanks creativepart, the pizza pan separator looks good. I was looking at baking pans but couldn't find a flat one without the edge. The pizza things all seem to be aluminum so the magnets won't work. It sounds like you have a rare steel one.

I haven't bought the magnetic mounting kit for the antenna yet but I do have the standard adhesive option. I think it would work well on a clean smooth metal surface so I'll probably go that way.

As for the technology, I'm kind of new to the cellular part of it. I know a lot of people have success with the cellular booster devices but I didn't like the idea of another cellular transmitter inside the coach and the possibility of feedback between them. It feels cleaner to me to have an external antenna to a box which is a transceiver and router. The other side of that is a normal local network with either Wi-Fi or ethernet cable. That doesn't help provide a good cellular signal inside but we don't really need that. If my somewhat expensive "unlimited" AT&T data plan from a reseller is any good, we can use Wi-Fi calling.

[SLOweather]

Rather than use a box for cable entry, I used Winegard cable entry plates, like this. They come in 1-4 cable versions. I have taken mine up several times to add cables.

[BobC]

VHB tape is very, very strong (140 lbs per square inch) and won't hurt your roof. It's foam cored so you can slice it off with something like a steel guitar string and then remove the adhesive with solvent. I'd use something like a 1" x 2" piece at each corner of the ground plane (or if round, every 90 degrees) and then cover the edges with Eternabond to keep water from getting underneath.

Personally, I'd opt for aluminum since the galvanized steel will rust over time. I'd adhere the antenna to the aluminum with VHB tape.

73, KJ6SVX

[tetranz]

Thanks SLOweather, that plate looks interesting although this antenna has quite a thick bundle of cables. That entry point may not be big enough. I only see a one cable version here https://winegard.com/industry/oil-an...e-entry-plates

I'm thinking something like this: https://www.amazon.com/dp/B07WL7D9V6 but it will be a squeeze for one of those holes too. They can handle 12mm diameter which is barely enough. The cable is five thin coax cables twisted together with a sheath around them. Two for cellular, two for Wi-Fi and one for GPS. I could probably remove the sheath, untwist them and use both holes. Of course the connectors need to pass through the hole or be removed and reattached. A plate avoids that.

I was originally thinking of getting a waterproof electrical type box, buying the glands and making my own entry box. I might still do that. Then I can make it with one big gland, (I see them online up to 40mm) and add smaller ones when needed.

[gurroz]

When we did ours we mounted the antenna on the top of our ladder and used the refrigerator vent to gain access through the roof. If I were going to drill a hole in the roof I would install a metal junction box that could accommodate any additional cables I might want to install in the future. Junction boxes seem to be easy to install, easy to waterproof and add versatility. I have seen installations where people have mounted their antennas on the junction box lid.

[golden13]

I just bought one, and it's recommended to bolt it directly on one of the upright pieces of the ladder itself. It is an omnidirectional antenna. I don't know if this helps you or not. Many RV roofs are coated with a rubberized waterproofing material, by the way.

Originally Posted by tetranz

Hi all

I'm not quite sure what forum to put this in. It's related to mounting a cellular antenna but it's not a technology question. Sorry if this is a bit of a long ramble.

New RVer here with a 2017 Minnie Winnie 31K. Among the many tasks we need to do before setting off with some cats is setting up good cellular data. I'm quite competent about the technical side of this but the thought of mounting an antenna and getting the cables in etc is almost keeping me awake at night. It's not the sort of thing I want to make a mess of and obviously want to drill the minimum number of holes.

I'd appreciate any comments and general sanity check on what I'm planning.

I have one of these Poynting "shark fin" type MIMO antennas that I want to mount on the roof. https://poynting.tech/antennas-and-a...nas/mimo-3-15/

Ideally, for performance, it needs to sit on a metal surface. With a fiberglass roof, this obviously means some sort of metal plate. According the manufacturer's instructions, the metal needs to be a minimum of 400 x 400 mm or about 16 x 16 in. Opinions vary on the necessity of it. It might not make a huge difference but, knowing what I do about antennas etc from being into ham radio, I'd like to provide that if I possibly can.

I've looked long and hard to find a good position. I think near the back on the left (i.e., not the ladder side) a couple of feet diagonally in from the corner. There's nothing else there, it's far away from the interfering A/C unit etc and I have a convenient DC power outlet for the router in the bedroom below.

It can mount two ways. One way is to have it sit over a central hole. It has a plastic spigot that goes through the hole with a nut on the inside. The cable goes vertically down through the spigot. I don't think I can realistically use this method. I don't want to have to deal with the space between the ceiling and the roof so any hole needs to come down into a cupboard.

The other way is to mount it on a flat surface with no hole. The cable goes horizontally out the back. Here's my plan. Please tell me of I'm suggesting something crazy here.

I get a sheet of galvanized steel. Probably this: https://www.amazon.com/M-D-Building-.../dp/B000IKM1Y0 It's 28 gauge or 1/64 inch thick which is thin enough to cut with tin snips. I'd cut it to 16 x 16 or maybe a little bigger. I would stick it down with 3M VHB.

The antenna has a magnetic mount option. They're six little "buttons" which are strong magnets. I'd use that to hold the antenna on the plate.

For the cable, I would drill a hole down into one of the cupboards at the back above the bed. I would follow what I saw in a video which is to mount a plastic box over a hole and have holes in the side of the box for a cable to go in and then down. That will give me the future opportunity to pass other cables in through the box without more holes in the roof.

Does that sound doable? I don't know how strong the VHB is and if it is likely to damage the roof. The antenna is quite light and when mounted pointing forward, it doesn't have much wind resistance.

Maybe a silly question. The salesperson mentioned the word "rubber" when talking about the roof but it is fiberglass isn't it?

Thanks

[NeilV]

If you want to be certain of safe mounting points and locations for drilling your best off calling Winnebago Customer Support who has a great reputation for sending out digital measured drawings showing where all plumbing, ducting, wiring and structure exists inside the coaches walls, floor and ceilings. Winnebago even embeds steel mounting plates inside the walls to support heavy items some of which are optional however the mounting plates will still be there hidden inside and they will reveal the locations of these too if you ask. This is a great resource that way to many Winnie owners overlook.

[Dlvgolf]

Originally Posted by Phil G.

I mounted my RV cellular antenna right onto the top handle of the roof ladder that came stock on the back of our motorhome. I ran the coaxial cable for it across the roof and down the refrigerator vent on the roof. I held the coaxial cable down on the roof surface using 3 inch wide Eternabond tape.

I didn't want to drill any holes into the roof or exterior walls. However, our roof is fiberglass, so the Eternabond tape works very well to hold the cable down and will last for years and years.

What kind of antenna do you have and do you like it?

[tetranz]

Originally Posted by golden13

I just bought one, and it's recommended to bolt it directly on one of the upright pieces of the ladder itself. It is an omnidirectional antenna. I don't know if this helps you or not. Many RV roofs are coated with a rubberized waterproofing material, by the way.

Thanks but I don't think we're talking about the same antenna are we?

I have one of these https://www.mobilemusthave.com/Poynt...na_p_1238.html

I don't think that could mount on the ladder. I haven't tried it yet so who knows but the technical blurb on this one sounds pretty good. I like that it's cellular and Wi-Fi so it can also be used to pickup park Wi-Fi and use that as the WAN to provide a local network inside the coach provider your router has that capability.

I plan to build a cable entry box like this guy does here:

https://www.youtube.com/watch?v=aB8ic6x9DAM

[Shedboy]

Have faced the same challenge on 2012 Navion but your choice of ant is more sophisticated than the vertical WiFi “whip” I chose but the mounting solution may be applicable.
I didn’t need a ground plane so used two pieces of aluminum box tube as a bridge across the top of the roof ladder tubes using U-bolts to secure them to the roof ladder horizontal tubes. You could substitute with a piece of flat Al sheet stock instead of the box tube. Drill a hole for the feed cable and mount the antenna on the Al sheet.
I used a steel Dish TV antenna mount (heavy and overly robust). It was easy to mount the whip ant to, route the feed cable and enabled raising or lower the whip from vertical position to horizontal. I replaced the mount hex bolts with wing nuts so I am able to raise or lower the “dish” mast by climbing the ladder. This is probably irrelevant to your situation.
My ant is fed with a USB cable. I tie-wrapped a piece of ½ inch ABS conduit to one of the roof ladder vertical tubes to route the cable from the roof to the under chassis of the RV and fed the cable through existing wiring holes in the RV floor to my PC in the entertainment center. I never added any holes to the RV.
The installation has been very successful. The remaining design issue is the possibility that I drive the RV away without lowering the whip ant, an issue that your ant selection solves if the ant is not the highest device on the RV roof. In my case, I have never needed to raise the ant to the vertical position to intercept WiFi although there is a potential signal phase loss.
Now I have an antenna farm on the roof, the WiFi whip, a Winegard Trvlr collapsible parabola, the stock TV dipole and a Sirius Satellite wip. All on a 24 foot RV roof!
The ant that you choose looks robust and trick! It states that it is omni-directional yet its form factor suggests that it is directional, curious! My installation impedes access to the roof because of the Dish TV ant mount and wip ant which is horizontal to the roof. Your ant choice will improve this drawback.

[tetranz]

Originally Posted by Shedboy

My ant is fed with a USB cable. I tie-wrapped a piece of ½ inch ABS conduit to one of the roof ladder vertical tubes to route the cable from the roof to the under chassis of the RV and fed the cable through existing wiring holes in the RV floor to my PC in the entertainment center.

That's interesting. If it's USB cable then I wonder if the antenna is more than just an antenna. Maybe it has some active device / transceiver / router at the base because you can't really send radio signals efficiently through USB cable.

Originally Posted by Shedboy

The ant that you choose looks robust and trick! It states that it is omni-directional yet its form factor suggests that it is directional, curious!

Yeah, I don't quite know what's in it. I think it is a collection of vertical whips in a line. It's going be a gamble to see how well it works. I have it because I bought this bundle https://www.mobilemusthave.com/Full-...dle_p_161.html plus the $120 per month data plan that MobileMustHave resells so I have a non-trivial amount of money invested in this. My partner and I are going to be close to full time RVing and both work full time remotely so we need good connectivity.

From being involved with ham radio for years, I know one of the "problems" with antennas is that they don't really have a binary "it works or it doesn't" condition. Any poorly installed piece of wire will "work" to some extent, it just a question of how well.

I did have a crazy idea of mounting the Pepwave router / transceiver itself in a box on the roof. The advantage with that would be that it would only need DC power and maybe ethernet cable going to it which has no practical length limitation in this application. I could then pass it under the coach like you but ... since the device cost about $500 I wouldn't like to lose it somehow.

In the last week or so with the RV at parked home, I've been testing the Pepwave router sitting inside above the microwave oven and it's been working quite well despite having a fairly weak AT&T signal so I'm somewhat optimistic about this.

I don't think I'll be mounting any more antennas on the roof but I might want to get a yagi on a pole to strap to the ladder when we're parked. That cable can come through the same box with some sort of connector to disconnect

[Shedboy]

Yes, it has an active device, the antenna itself has an “N” connector that the active device connects to directly. It does everything the manufacture claims. I referred to it a “whip” but it is most likely a stacked vertical co-linear array with integrated thinfilm balun. It is very well made, commercial quality.

CC X Mile Long Range Omni Receiver - Windows Only Item # XMILE8 Great for your RV, Big Rig, Boat, Home or Remote Business
$119.99

OFF THE WALL – A “thumb drive” USB WiFi adapter can be mounted on a satellite dish antenna in place of the LNA/LNB and “scab” free WiFi from Panera, etc. It works over a mile away but takes a long time to get the thumb drive at the focal point of the parabola and align the parabola to Panaera.

I replaced the original steel tube that the satellite antenna mount
used with 1½ PVC drain pipe to reduce weight. The ½” PVC conduit is
tie wrapped to the ladder vertical tube. For larger cable bundle,
increase diameter of conduit.

[Shedboy]

Photo of installation, antenna lowered in horizontal position, transceiver & conduit somewhat viable. All mounting hardware sourced at Home Depot.

[Shedboy]

Sorry, pix too big to download - One other wild idea - check-out your roof A/C cabinet (housing). If possible (is it a clam shell type?) buy the top half from the mfgr, pop-rivet the 16x16 Al ground plane to the top inside and mount the MIMO ant on the outside. Use the AC holes in the roof for cabling.


This is a lot of trouble but meets the objectives and optimizes the electrical performance of the MIMO and no new holes in the RV (maybe), Also if ant hits low tree branches the damage will probably be limited to the AC cabinet (you have the original to replace it with).


Don't know about the esthetics.............

[tetranz]

I hadn't thought of mounting it on the A/C unit. Interesting idea and it would still be within height limits but ... probably not. I've pretty much decided to stick down a metal plate for a ground plane with the antenna on it and then a cable entry box basically following that Tito video I posted earlier and this one which decribes much the same thing.

https://www.youtube.com/watch?v=IhiNPRF0x48

I'm going to stick the box down with double sided Eternabold and then Dirco around the edge and secure the plate with single sided Eternabond around the edges. That seems better than double sided tape under the plate.

I'm still a little stuck on what tool I should use to (carefully!) drill the hole. Both those videos use a cone shaped titanium drill but then that one above flashes a message saying not recommended for roofs, use long bits but I don't quite know what that means. I want to drill about a 1 inch diameter hole. I don't think I want a bit that size.

I have a hole saw kit https://www.amazon.com/gp/product/B07FVN82B2 Is that the right tool for a the job? I realize that the best answer is probably "don't drill any holes at all" but I think I really need to bite the bullet and do this. I guess I'd drill a small pilot hole up from the roof of the cabinet where it needs to come down but then use a hole saw or a cone bit to drill the main holes. The pilot hole will need a long bit. What sort of precautions should I take?

I'm also not quite sure what sort of roof I have. It's a Minnie Winnie 31K. Winniebago brochure says "fiberglass". Salesperson used the word "rubber". I'm pretty sure it's just whatever manufacturer put on. I need to clean the areas where I'm going to apply the Eternabold. Should use some acetone or alcohol? It's already quite clean so maybe just soap and water?

That Tito video looks like a vinyl roof how he cuts out a circle with a knife at about 4:40.

Thanks for any further advice.

[NeilV]

Why not just use a cellular antenna designed to be used on non-metallic surfaces?

[tetranz]

I bought the Poynting and the Pepwave router as part of a bundle. I think it's quite a good choice. A ground plane helps performance but even for this one, it's not essential so I could do without the metal if I really wanted to. The metal plate is not really a problem.