How to Make an Omnidirectional TV Antenna
Building an omnidirectional antenna for HDTV signals will allow you to receive signals in any direction that are in range of your antenna. These HD (high definition) signals are broadcast free from towers that are in your local area, so all you need is an antenna, and an HD ready TV. Simply constructing a few coat hangers on a board and connecting them with copper wire and a balun will have you enjoying the high resolution and crisp sound from your HDTV.
Things You'll Need
- 4 metal coat hangers
- Measuring tape
- Wire strippers/cutters
- Sandpaper, 150 grit
- 1 x 4 wood board, minimum 3 feet
- Circular saw
- Carpenters pencil
- 8 wood screws, 1/2 inch long
- 8 washers, 1 inch diameter
- 6 feet insulated stranded copper wire
- Utility knife
- 75 Ohm balun
- Safety goggles
Cut the hooks off of each coat hanger with the wire cutters. Using the pliers, bend each of the coat hangers into straight wires, so they are perfectly straight. Sand off any paint or baked on enamel using the sandpaper.
Measure and cut the coat hanger wires into eight wires that measure 14 inches long. Take each of the 14 inch wires and bend them with the pliers into the shape of a V so each side of the V is seven inches long. Bend them until the distance between each leg (or top of the V) is exactly three inches wide.
Cut the 1 x 4 board to 36 inches using the saw. Lay the cut board, down flat on the table and label the one end as the top.
Measure down from the top end of the board (mast), and make a pencil mark at the 5, 10, 15, and 20 inch measurements. Make the pencil marks about one inch from the left edge of the board. Repeat this step to make four identical pencil marks down the right edge of the board, starting from the top of the board.
Lay the small bend of the eight V-shaped wires over each of the eight pencil marks from step four, so that the legs point away from the board. Screw down a washer on the mark so that the washer clamps down on the bend of the V-shaped wire and secures it in place. Do not completely tighten down the screws.
Cut a 30 inch length of stranded copper wire. Strip two inches of insulation off one end. Wrap the stripped end around the screw in the top right corner, but under the washer. Cross the wire over to the two middle screws on the left side and wrap one loop of the wire around each screw. Cross the wire back over and wrap the wire around the screw in the bottom right corner. Where the wire is wrapped around each screw, use the knife to cut away two inches of insulation so the wire makes good contact with the screws. Make sure the wire is wrapped one time on each screw. Cut away any extra wire.
Repeat Step six to attach a new piece of stranded wire to the screw beginning in the top left corner and finishing with the screw in the bottom left corner.
Connect the 75 ohm balun leads to the second set of screws from the top of the antenna mast. Attach one lead to the screw on the left and the remaining lead to the screw on the right. Tighten down all the screws on the antenna to secure the wires in place.
Screw in the male connector from the coaxial cable from the TV to the female connector on the balun. Turn on the TV and test for reception.
Tips & Warnings
- Use extreme caution when operating the power saw, as contact with the blade while it is running could cause a serious injury.
- Be sure to use the safety goggles to avoid injury to the eyes from debris when cutting the wood or wiring.