Damir Systems Inc.

The other day we decided to try out the HDTV reception over the air (OTA). We are close to the CN tower, but facing away from it and shielded from the signal by a building. For starters I ordered a  nice indoor antenna from DELL. Works nice, however could not pick up more than three channels in one position. For more channels we had to constantly move the antenna. Tried it at a neighbour’s who faces the tower, perfect. However, we have to rely on signal-bounce and this one seem to be too directional for that.

Good news was that it was a time to tinker a bit. It has been a long time since I calculated some antennae, but with a help of the ARRL Handbook and some web search I was quickly in business.

Here are some antenna configurations I have tried:

• two spoons (tea spoon-dipole),
• two paper clips,
• two tape measures,
• tape measure + tea strainer,
• coat hanger antenna (without reflector),
• aluminium foil + resistor (T2FD = tilted terminated folded dipole).

All of the above configurations worked as well as the fancy commercial antenna, check out some pictures. The last one proved to be the best, we get six channels in one spot and takes a small move to get one more channel.

This is what it takes:

• Some aluminium foil (usually found in the kitchen).
• One 390 OHM resistor (1/8 or 1/4 W).
• TV matching transformer 300 to 75 Ohm (cost = $1).
• A piece of coax cable (already attached to the TV).
• Scotch tape to keep it in place.

This works better (at our location) than the fancy commercial antenna. At the end it was mounted on a 12-inch wooden ruler and a wooden salad-spatula bracket was added to support the transformer and the coaxial cable. A nut (1/4) was super-glued to the bottom of the spatula to allow tripod-mounting. Anything looks good mounted on a tripod. Here is the final configuration.

With this we can get the following HDTV channels:

If you feel like trying, and are close enough to the tower, here is the procedure:

1. Find a 12 inch wooden ruler or piece of cardboard 12×2 inches;
2. cover it with aluminium foil and secure the foil using scotch tape;
3. download the template and print it, make sure it is not resized during the print;
4. place the template over the foil and cut through with an X-Acto knife;
5. remove the excess foil, make sure the loop stays aligned;
6. mount the ruler on a support (a spatula will do) to form a T, using glue or adhesive pads;
7. mount the TV matching transformer to the spatula;
8. slide the transformer leads below the aluminium foil and tape over;
9. slide the resistor leads below the foil and tape it in place;
10. attach the coaxial cable to the digital signal input of your TV.

Notes:

• Your TV must have a digital (ATSC) tuner for this to work.
• Somewhere in the TV setup menu you should select antenna instead of the cable input.