A simple web search of "DIY HDTV antenna" yields dozens of plans for making an antenna to receive HDTV channels over the air. It's better than the old days of antenna reception, though, because digital signals are an all or nothing affair; you either get the signal in all its high definition beauty, or you get nothing at all.
HDTV With Coat Hangers
Homemade HDTV antenna design can surprisingly be done with simple wire hangers, aluminum foil, and a 2-by-4 about four feet in length. Alternatively, you can use a 1-by-4 for an HDTV antenna for inside use.
Straighten ten wire hangers. Cut off the top and squiggly section of each. Make eight straightened lengths into a "V" shape by bending them in half, and precisely place them on the narrow side of the 2-by-4, or the wide side of the 1-by-4, precisely 7 inches from one another.
You'll use a total of 10 hangers, because two more crisscross the V-shaped wire arrangement to make contact between them. Four hanger "V" sections are placed on each side of the wood. This creates the appearance of bow ties, which is why this is design is often called a "bow tie antenna."
The aluminum foil reflector, if used, aids reception by bouncing signals to the wire bow ties, in the same way that a dish bounces signals to the transponder that sends satellite signals to the receiver connected to a TV.
Two Ways To Go
The 2-by-4 design is more for an attic or outdoor mounting; the 1-by-4 design is better for interior placement. With the 2-by-4, mount everything to the narrow side of the board; with the 1-by-4 design, mount everything on the wide side of the board.
Make a mark 7 inches from the top of the 2-by-4 or the 1-by-4. Then make three more marks, each mark 7 inches from the previous one. Between the second and third marks, draw a horizontal line at the 3 1/2-inch point; this is where the matching transformer attaches.
Drill pilot holes at each mark for the screws. Then, using a screw and washer, screw each to the wood half way. Be sure none of the washers touch one another.
Attach each "V"-shaped hanger to the wood, four on each side. Be sure the point of contact between the hanger and washer is free of paint or grime.
Secure the last two hangers. Start at the top of each "bow tie". Connect to the second bow tie on the opposite side, and down this side through the third bow tie. Make the final connection on the fourth bow tie on the same side as the first "bow tie". Wherever these hangers touch, at least one should be insulated.
Tighten each screw firmly, and check that each hanger segment angle is equal, and parallel to the work surface. (If the backing reflector is being used, the hangers should be parallel to the backing reflector.)
Screw in the matching transformer—aka "balun", aka UHF/VHF adapter—at the midpoint of the wood, between the second and third bow ties.
The Backing Reflector
The backing reflector can be constructed with 30-by-16-inch plywood. Alternatively, heavy cardboard, metal shelving grates, or old oven shelves can also be used. In any event, aluminum foil is used to cover the side of the surface that faces the hangers. The opposite side is secured with heavy duct tape, especially if the antenna is placed in humid or outdoor environments.
This backing reflector improves reception by bouncing the signal waves to the hangers, in the same way a satellite dish bounces signals to the transponder that is facing it. It is optional when the antenna is mounted indoors.
Attachment to the TV
Connect the UHF/VHF transformer to the TV or receiver using a standard 75-ohm coaxial cable. Adjust for optimum signal strength, and enjoy your homemade HDTV antenna and free HDTV channels.