Installing a Little Tarheel II on a 2016 Jeep JK Unlimited
This is Part 9 of Outfitting a Jeep JK Unlimited for Ham Radio. In this part, I will explain how to mount a screwdriver antenna to the Cargo Door. This Part will NOT address pulling coax through the Cargo Door, nor does it use the manual control switch supplied with the antenna.
To control the antenna, I use the TuneMatic Lite by JT Communications. You can read about that installation in Part 6.
Amateur Radio Equipment to Install
- Little Tarheel II Mobile Screwdriver Antenna
- Comet-NCG HD-5 Lip Mount
Tools and Equipment Used
- 9/16-Inch Socket
- Hex Screwdriver Set
- X-Inch Adjustable Wrench
Step One – Hitch Lip Mount to Cargo Door
The HD-5 mobile mount assembly comes with the largest lip mount offered by Comet-NCG, the RS-840. It features an extra support tab to minimize lateral movement, and can accommodate antennas up to 80-inches in length. A Diamond K-400 works equally as well.
The best place for any antenna is where you clear the roof of the vehicle. This configuration is not possible on a Jeep, especially ones with a soft top. Here, I hitched the lip mount to the cargo door. The hex screws on the back of the mounting tab will cut into the paint. While that may sound like a bad idea, it actually makes contact with the metal inside the cargo door. We want such a connection so we can ground the antenna later.
Step Two – Fasten Screwdriver to Lip Mount Assembly
Next, we attach the motor that is the heart of the screwdriver antenna. Here you will notice that the center conductor of the coax connects to the antenna while the braid connects to the mount. We will take advantage of the braid later when we start the bonding and grounding process on this antenna.
Please make certain that you torque everything well. Vibration will knock everything loose and cause you a world of noise and grounding problems.
Step Three – Attach 32-Inch Whip Antenna
Now use an adjustable wrench to attach the whip antenna to the top of the motor unit.
The Little Tarheel II comes with a 32-inch whip for operation between 3.5 MHz and 54 MHz. You can purchase a 56-inch whip that will improve operation on the lower end of 80 Meters, but you still cannot tune this antenna to 160 Meters.
Step Four – Connect Antenna Controller
Finally, connect the other end of the antenna controller to the motor unit.
Here is the final assembly.
How is this off road? I am considering a Little Tarheel II for my JK and am debating between a lip mount such as this, or welding a mount to my steel quarter armor.
If I did it again, I would weld the mount to a quarter panel. The LTII is heavy for the Comet Mount. I tighten the screws on each axis after lots of rocking and rolling in the back country.
Thanks! I saw a few reports of this antenna failing (e.g. the aluminum mast itself) due to offroad use, and I’m a bit concerned. Something about the moment of inertia being very high from the base, causing torque and metal fatigue. I’m considering the LTMT1 mount and then bolting it to trail armor…which I don’t even have yet BTW. The bracket contacts the mast much higher than the UHF (?) connector, so hopefully it can mitigate the torque. I am not sure what mount they used, and I cannot find the post right now.
I purchased a Smittybilt SRC Roof Rack and need to move the antenna. Once I get the roof rack installed, I plan to use an LTMT1 to mount the antenna to the rack. Since the roof rack connects directly to the Jeep itself, I may not need to bond it further (but I am holding final decisions).
I also think I want to change the whip to something longer. I may go with the MFJ 758-2742, which is a 12-foot whip.