The homemade wire coat hanger HD antenna has become sort of a phenomenon. The main reason is its incredibly low cost, from next to nothing, if the parts are just laying around, to about £6 for a motorised version. The second reason is that the simple construction pulls in stronger signals than are readily transmitted by the cable and satellite TV providers, with program name and more information available on-screen. Actual construction can take 30 minutes to an hour, so it doesn't take much time, in addition to getting great signals for free.
Check what you've got laying around. If you don't have wire hangers, get them from a laundry. If mounting outside or in an attic, a metal grate or old oven shelves can be used instead of wood for the reflector. Get the screws, washers and transformer, all very economical if they're not already lying around.
Gather your tools, and decide on outdoor or indoor installation. For use outdoors or in attics, use a 2x4; for use indoors, you can use a 1X4 for greater portability.
Assemble the reflector by wrapping the plywood, metal grate or shelving or cardboard with aluminium foil. Secure the foil on the back of the surface with high-temperature duct tape. Then place it atop the 2X4, centre it, and nail or screw it to the 2X4.
(Note: This is only a step for attic or outdoor placement, but it can improve indoor reception.).
Mark the bow tie placements. 7 inches is optimum. Mark down from the top of 2X4 or the 1X4 if the antenna is staying indoors. Then mark each 7-inch section: there will be four. Between the second and third mark, draw a line at the 3 1/2-inch point; this is where the matching transformer attaches.
Prepare the hangers by straightening each one and cut off the curved top of the hanger. Next, cut off the squiggly opposite end of the hanger. Make each straight length 14 inches long, and fold each of them in the centre to make each "V."
Screw in the screws with washers. Only go half way, but place them all on the board, making sure none of the washers touch. Take each prepared hanger section, making sure each contact point is free of paint or grime. Screw each hanger section lightly to the board.
Secure and connect all parts of the antenna. Run the two remaining hangers or Romex or other solid wire from each top "bow tie" and down the opposite side through the third bow tie, making the final connection on the fourth bow tie on the same side as the top bow tie. The wires will cross between the first-second, and third-fourth bow ties, and at these crossing points, at least one wire should be insulated. Tighten each screw firmly, and check that each "V" segment angle is uniform and parallel to the reflector or work surface. Finally, attach the matching transformer, aka "balun," aka UHF/VHF adaptor, to the 3 1/2-inch mark between the second and third bow ties.
Install the finished antenna in the attic or outside. If built with the 1X4, position the antenna for best reception in a corner, behind the flat screen or wherever else the signal is strongest.