Installing a VHF/UHF Mobile Antenna on a 2016 Jeep JK Unlimited
This is Part 6 of Outfitting a Jeep JK Unlimited for Ham Radio. In this part, I will explain how to install a Dual Band Antenna in the front of the Jeep, and then snake coax through the bulkhead.
This process took about an hour to complete, thanks to influence from Bob, K0NR.
Amateur Radio Equipment to Install
Tools and Equipment Used
- Power Drill with 5/34-, 3/32-, and 7/64-Inch Drill Bits
- Phillips-Head Screwdriver
- Black Sharpie Pen
- Wire Coat Hanger, cut so you can use it as a wire snake
- Gorilla Tape
Step One – Preparing the Bulkhead
The Jeep JK Unlimited has a 3/4-inch hole in the bulkhead on both the Driver’s and Passenger’s side of the dashboard. The hole is filled with Styrofoam, which provides stability for the RG-58/U coax we will snake through it. This is the same process we used to install the FT-857D’s electrical system.
Push a wire coat hanger through the Styrofoam until it comes out the engine side of the bulkhead.
Leave enough coat hanger to attach the coax later.
Step Two – Mount the Larsen Straight Bracket
The Larsen Straight Bracket has three holes for the sheet metal screws provided with the kit. Align the side with the sheet metal holes with the convenient square hole located on the front quarter panel. We will use this square hole to feed the antenna coax later.
Next, mark the holes using a Black Sharpie Pen. Then, using a 1/64-inch bit, drill a hole in the mark closest to the square hole. In this same hole you just drilled, use progressively larger bits to make those holes larger. I used bits of 5/34-, then 3/32, and 7/64-Inch.
Fasten the first sheet metal screw, and repeat this process with the remaining sheet metal screws.
Step Three – Snake Coax Through the Bulkhead
Feed the coax through the square hole next to your antenna bracket.
Wrap enough Gorilla Tape to join the coax to your coat hanger.
Pull the coat hanger (and the coax) into the driver’s side of the bulkhead. If the coax slips off of the coat hanger, take the coax to the driver’s side and push it through the bulkhead to the engine block. This method will make the hole in the Styrofoam large enough to accept the coax. Pull the coax out, tape it to the coat hanger, and try again.
Step Four – Fasten the NMO Antenna Mount
Once the majority of the coax is inside the cabin, fasten the NMO mount to the straight bracket.
At this point, you also can mount the antenna.
Step Five – Snake Coax Through the Cabin
Regardless of where you plan to mount a radio, the coax inside the cabin should be out of the way.
There is a plastic rail along the floor where the door seals to the vehicle. The top of the plastic rail opens just behind the door straps. When you feed coax through this slot, it will be out of the way of your feet as you drive, or as you get in and out of the Jeep.
From this point, you can take the coax anywhere in the vehicle. In my case, an FT-857D rests under the passengers’s side seat. The plastic rail allows me to snake the coax just behind the seat bolt on the floor. You should take this path to get the coax across the mid-line of the vehicle.
Things To Do Later
Larsen provides 17 feet of RG-58/U with its mounting kit, which is more than we need if the radio is located under the driver’s side seat. Later, we will cut the coax to a custom length to shorten the distance between the antenna and transceiver in order to reduce line loss.