If you're a ham radio enthusiast or you're thinking of taking up the hobby, you've probably dreamed of putting an antenna tower close to your home. This is a serious undertaking, but the benefits to your radio performance will be worth it. The most important part of installing an antenna is the base. A properly installed concrete foundation will protect your tower and your home.
Dig a square hole 5 feet deep and 20 percent larger per side than your tower's footprint. Position the hole a distance of 1.5-times the height of your tower from any structures.
Construct a metal frame out of rebar. Use the #6 rebar to make four vertical posts. Cut each to 5 feet long, then bend 2 inches on each end 90 degrees in the same direction. Cut three 8-foot lengths of #4 rebar, and bend them into 2-foot-by-2-foot squares. Using the baling wire, connect the four vertical posts to the corners of the rebar squares. Place two squares 15 inches from the top and bottom of the verticals, and another in the middle.
Using the remaining #4 rebar and baling wire, attach the threaded anchors included with the tower kit into the center of the steel frame. Space the anchors to match the holes in the tower base, and wire them in parallel to one another. The anchors must extend at least three-quarters of the way into your concrete base, or 4.5 feet in this case. Make sure there is plenty of thread sticking out above the frame for you to attach the tower to after you pour the concrete.
Pour the aggregate gravel into the hole to a depth of 4 inches. Level this layer.
Place your metal frame in the hole. Make sure there will be 4 inches of concrete separating all sides of the frame from the ground, to prevent sparks in a lightning storm.
Check the anchors to make sure they are exactly plumb, or vertical. If they are not, your tower will lean. Adjust the gravel layer until they are plumb.
Mix your concrete in a concrete mixer. You can rent a concrete mixer from a home improvement center. Pour concrete into the hole, and allow it to cure for 30 days before attaching your tower.
While this is a do-it-yourself project, having a professional install your concrete will save you a lot of time and worry.
All metal in the frame must be connected together and insulated from the ground to prevent sparks during an electrical storm.