Antenna Mounting on Roof

[Markh1254]

I am a ham radio operator and would like to install a UHF antenna on the roof my Tradesman. Installing it entails drilling a 3/4" hole in the roof with a shallow metal hole saw, fishing the coax cable through the headline, down on of the pillars and slipping the NMO mount in the hole, tightening the antenna mount, which seals with an O ring. This is a common practice on public safety vehicles.

My question is besides the crossmembers tht run side-side at the pillars; front (A) mid (B) and back (C) on my crew cab, what else is up under that headliner? My plan is to drill the hold between the B and C pillars, centered side to side. Does anyone know of any harnesses or other surprises that might lurk underneath that headliner?

Thanks again,
Mark

 

[gsbrockman]

Remove the A, B, and C pillar trim on one side, and drop the headliner down for a peek. Can’t remember for sure.....but the seatbelts may have to be loosened and/or removed, too. There may very well be various harnesses for the rear interior lights attached to the headliner.

 

[monovasia]

I am a ham radio operator and would like to install a UHF antenna on the roof my Tradesman. Installing it entails drilling a 3/4" hole in the roof with a shallow metal hole saw, fishing the coax cable through the headline, down on of the pillars and slipping the NMO mount in the hole, tightening the antenna mount, which seals with an O ring. This is a common practice on public safety vehicles.

My question is besides the crossmembers tht run side-side at the pillars; front (A) mid (B) and back (C) on my crew cab, what else is up under that headliner? My plan is to drill the hold between the B and C pillars, centered side to side. Does anyone know of any harnesses or other surprises that might lurk underneath that headliner?

Thanks again,
Mark

I assume u r talking VHF/UHF? I looked at it and opted mounting my tri-band antenna drivers side hood mount ( clam shell )... works very well... I have an oldie Kenwood TM-741a with the remote panel which fits perfectly on the console... and I mounted the body in the center console and actually power up with the cig lighter receptive... I have a remote speaker mounted on the floor backseat bulkhead. Hope this helps...

73’s KA3ZHX

 

[lpennock]

Just a FYI. There are NMO cables that only need a 3/8" hole not that it matters much once you are drilling holes. 73 AD7AS

 

[BigPapa]

Unibits are MUCH better than a hole saw for what you’re doing.

 

[Markh1254]

Just a FYI. There are NMO cables that only need a 3/8" hole not that it matters much once you are drilling holes. 73 AD7AS

I considered the 3/8" mount and decided to go with the 3/4" mount for two reasons: With the 3/8" mount you need access to the backside and I'd really rather not have to take down the headliner with my fat hands. The 3/4" mount you can tilt and get in. The second reason - they make a snap in plug to seal the opening if I ever remove the mount from the roof. 73 de NO8J

 

[Markh1254]

Unibits are MUCH better than a hole saw for what you’re doing.

View attachment 127762

I agree a regular hole saw is made for cutting wood, not steel! I considered using a Unibit but found this specialized hole saw made just for installing these NMO (new Motorola) mounts. It has more (fine) teeth and is very shallow - less chance of going through the headliner. While the specialized hole saw wasn't cheap ($55) it's what is used to install these mounts on public safety vehicles. Here is a description of this hole saw: https://www.talleycom.com/images/pdf/ANXHS34.pdf I had very good service from the www.theantennafarm.com for both the NMO mount and special hole saw.

 

[Topzide]

@Markh1254, I like the saw link and have saved Antenna Farm link. I only have a CB on a fender mount for use on the highway and have thought about moving to the roof with a NMO mount and an adapter for 3/8-24 thread. You can tip the head liner quite a bit to get your hands up there. I'm like you and have big "paws", let alone they don't work as well as they once did! I would also put an automotive type sealer under the mount along with prep bare metal with paint! I know that there's an o-ring on the mount but a little extra prep will help in the long run! Years ago, I had a sunroof cut into the cab of a Toyota truck that never gave me a issue with the extra prep from the start. Sold truck and when it was totaled in an accident, was able to get access to pull sunroof to see if there was any rust and after 16 years with sunroof, no rust along the cutout! The guy that installed really did it right. If you're punching holes into roof, take extra time to prep for the long haul. good luck on the project! Post pictures when done, very interested in the outcome!

 

[AH64ID]

I would still use a unibit. It’s much cheaper and still better for the sheet metal.

When I installed my cab clearance lights I need to drill a 3/4” hole for every light. The unit it worked great, and I would do that again even over that specialized hole saw.

 

[BigPapa]

Your going to have to remove the a-pillar covers and the overhead display at the least. I’d just go ahead and take the headliner down where you can see what you’re doing instead of blindly cutting a hole from the top.

 

[Mikey-KE7LBB]

I used one of those step drill bits when installing a 2M antenna on my '09... I pulled the interior light and drilled from the inside out. I routed the coax down the passenger side "B" pillar to the FT-857D under the seat. The head is mounted on a PanaVise flex mount that's attached to the trans tunnel with some self tapping screws.

 

[Cummins12V98]

"I agree a regular hole saw is made for cutting wood, not steel!"

Not sure where you got this idea. They are designed to cut steel but also work fine on wood and many other materials.


"LENOX WOOD & METAL CUTTING BI-METAL HOLE SAWS" Nothing too special about these. Most hole saws are considered Bi-Metal.

 

[TJJEEPER]

They actually make a hole saw for drilling antenna mounts. It has a short pilot bit and shoulder so you don't over penetrate. I used to do this for a living. We used a spedo cable as a fish wire. In my '06 there was foam filler in the pillar between the front and back doors. A real PITA to fish that. I'm using a trunk lip mount on the hood on the driver's side on the '12.

Hole Saw
#ad

Antenna on '12 (have sunroof)
#ad


Greg
NZ6E

 

[AnonEd]

I second the unibit and headliner droop. But I'll be that guy and suggest considering a run down the C pillar just to avoid the side curtain airbags I think it might have?

 

[gsbrockman]

I second the fender mount.... @TJJEEPER

 

[SSage]

I've been using the Breedlove antenna mounts for years, another good option. The have nice heavy duty mounts and pucks. The stake pocket stuff is nice and strong too. The NMO bases are very rigid if your running the longer whips, its a nice set up. https://breedlovemounts.com/store/ols/categories/nmo-mounts

 

[ChrisStevens]

As TJJeeper said, I got the special drill for NMO drilling. I didnt pull my whole head liner, just removed the trim from drivers side and slid a box in there to space it out from the metal. Drilled out the hole and had a small pan to catch the hot disc that fell out. Enough room to put my hand in there and hold the bottom of the NMO while I tightened the top. Pretty easy compared to a lot of vehicle's I've had to do