How to Erect a 20-Foot Antenna Tower

By Lawrence Harris

Depending upon your roof height, a 20-foot antenna mast may not need guy wires.
i Rooftop Television Antenna image by ryasick from

Maybe you're a ham radio operator setting up a new rig, or maybe you're just a guy who wants to stop paying $80 to $120 per month for satellite TV and still get your digital, high-definition television fix by tuning in over-the-air HDTV broadcasts from your local TV stations. With a 20-foot antenna tower, you'll have much better results trying to pull in those faraway stations that were impossible to receive with your old pair of rabbit ears. Our 20-foot antenna mast will require 25 feet of mast pipe so that the base of the mast can be buried for good electrical grounding and stability.

Decide where to install your antenna tower. Make sure it's far away from overhead utility lines (especially power lines) to avoid electrocution hazards. You'll be burying the base of the antenna mast between 2 and 8 feet below grade, depending upon local building and electrical codes. The antenna mast should be erected right next to the roof fascia or gable end so an antenna mast mounting bracket can be attached there. Hand-dig your hole (about 8 to 12 inches in diameter) with a post-hole digger or shovel before attaching the mounting bracket. This way you can ensure your hole and bracket won't have to be moved due to a conflict with an underground utility line, tree root or boulder.

Figure out the bracket mounting location. Do this by using the bracket and a plumb bob to dry-fit the bracket at the correct spot, directly over the hole you just dug. Mark the proper bracket-mounting location with a pencil. This way you'll make sure the mast will be plumb when it is installed in the hole.

Mix up a small batch of concrete according to the package directions. Pour about 6 inches of concrete into the bottom of the hole and let it thoroughly set. This is the foundation upon which your antenna mast will rest; it will keep the mast from slowly sinking into soft sediments.

Install the antenna mast mounting bracket to the fascia or gable at the marked location using the included hardware.

Attach the assembled antenna to a section of mast pipe using the provided hardware. Make sure the antenna is mounted right-side-up, with the bottom of the antenna facing the male end of the antenna mast pipe.

Spray the male ends of the mast pipe sections with WD-40 and fit the mast sections together. Attach the top section (with the antenna mounted to it) last. The WD-40 is optional, but it really makes it much easier to fit each mast section together securely, especially if you have no access to a helper for this step.

Find a helper to help you raise the antenna. Ideally, one of you should be on the roof to grab the top of the antenna as you raise it up to roof height. The "ground" person should then guide the bottom of the mast into the mast hole while the "roof" person holds the mast against the roof mounting bracket. Then the "ground" person checks the mast with the carpenter's level to make sure it's plumb.

Attach the mast to the roof mounting bracket using the supplied hardware. Before the final tightening of the nuts, check the plumb of the mast one more time. After the bracket hardware is tightened down, backfill the hole, tamping the soil into the hole as you go. The antenna assembly is now ready for final aiming and connection to the downlead wiring.