Thursday, July 23, 2009

A Simple Low-Cost HDTV Antenna

Prior to the recent digital TV changeover, I was using several 7.25” ring antennas mostly made of thick copper wire. Since then, I’ve noticed that the reception was rather poor on some stations. I tried making a few of the bow-tie antenna’s that are shown on video and pictures around the web, but found them to be clumsily large for an indoor antenna, as well as hit and miss on a few dimensions.

While experimenting with a few shapes of formed metal rods, I came across a 16” by 4” steel rectangle that used a quarter inch rod. After connecting the split ends to a 300/75 ohm transformer (balun) and then to a TV input, I was amazed that all the local channels came in.

I’ve made a few others using copper wire and three-eight’s inch tubing, and they work great. With tubing, simply cut out a right angle section at each corner so that when bent inwards, it forms a 90 degree corner. Place a wooden or plastic dowel between the open ends at the connection. Coat hanger wire and thin copper wire will work, but not as well as material between one quarter and three-eighth’s inch diameter metal.

If this size does not work well, try an 8.25” x 8.25” square.

So far I've mounted the frames on wood or plastic with hot glue.

Here are the dimensions: