Antenna mounting on a JKU

[Slolane]

I just bought a Yaesu FTM-400XDR to install in my Jeep JKU. I’m still not sure where I want to mount the hardware. Looking at antenna mounting, I think I’ve narrowed it down to 2 spots. First is on a bracket that is on my spare tire carrier. It is the highest place on the vehicle except the roof.

The other spot is on the front of the windshield using a light mounting bracket as shown in the picture (with the antenna in place of the light obviously)

Any advice on what would be the best choice? I have a CB antenna that is also mounted on the rear, about 3 feet away from the UHF site. Also is there any issue running the coax along side the one for the CB and wiring for the 3rd brake light?

Also any suggestions for mounting the radio body? I’m looking at under the passenger seat but would like to avoid that area due to possible water damage.

All comments appreciated!

 

[El-Dracho]

The mounting of the external antenna is of particular importance for the performance. When selecting the mounting location, we are faced with a conflict between good transmission and reception performance and practicality. From a radio engineering point of view, if range is important, then
the antenna should radiate freely in all directions. So a good position would be in the center of the roof, where the antenna sits as high as possible and has a good reflection surface with the roof. On the other hand, the antenna for an off-road vehicle should be located where it is not too endangered by objects such as low hanging trees or the like, does not unnecessarily increase the vehicle height and can still radiate and receive well.

So it is a compromise. I have my CB antenna on the fender and my 2m/70cm antenna on a bracket in front of the hood. I wanted to have these far away from the vehicle electronics because of the power of 50W after all. I fitted the radio unit under the seat.

I think there was a nicely documented installation in a Wrangler here the other day. I will search for it and if i find it I will link it here.

 

[Prerunner1982]

That spare tire mount isn't too bad, it's up high enough for part/most of the antenna to clear the roof, it's above the spare tire (steel belts) and other metal. You may need to remove some of the coating on the underside of where you mount the antenna to that it makes good connection with the metal. If the antenna is a 1/2 wave 2m antenna it doesn't need a ground plane so it won't be such an issue at least for 2m, 70cm requires very little ground plane. It's always better to have a ground plane even if it's a 1/2 wave antenna.

Coax running next to coax isn't an issue, next to the power wire may or may not be an issue but I doubt it would be with just 3rd brake light wiring. LEDs could cause issues though, just something to keep in mind.

As far as mounting the body of the radio, look behind the knee panel below the column. There may be enough room down there and maybe even some metal brackets you could tie into for mounting.

 

[JeepingMike]

I have the dual band antenna mounted on the hood. Excellent receive and transmit for me so far. My FTM-400 radio body is under the passenger seat and I have done wheel well water crossings without enough water inside to be an issue.

 

[John Bishop]

I currently have my antenna mounted like JeepingMike does. One of these days I’ll get around to relocating it. I’ve had it “adjusted” by tree branches on tight trails numerous times.
I went the lazy route and mounted the radio body to the side of the center console by my leg. It hasn’t been in the way while driving. The head unit is mounted on the dash via Ram mount to a Vector Offroad bar.