If you don't have cable or satellite or if you just want a backup for when those services go out and you want to pick up local DTV stations you can build a Gray-Hoverman antenna.
Step 1
In the drawing, the green lines are guidelines and the red lines are the wires.
Step 2
Set up the guidelines:
- Establish the center of the board.
- Draw the center horizontal guideline
- Draw the other 6 horizontal guidelines
- Draw the center vertical guideline
- Draw the other 6 vertical guidelines
Step 3
Everywhere a wire and guideline crosses, center punch and drill a small hole (smaller than the screws) through the backboard.
Step 4
Put screws in the holes and use the resulting jig for bending the wires making sharp bends and keeping the wire as straight as possible between bends.
Step 5
Remove the screws from the backboard and set the wires aside.
Step 6
Drill the holes so the screws can pass through them.
Step 7
Drill/Cut a hole at the center of the backboard big enough for the BALUN to pass through.
Step 8
If the BALUN has screw terminals on the ends of its 300 Ohm wires, cut them off and solder 6” extensions made of stripped Cat 5 or phone wire to the 300 Ohm leads.. Set the modified BALUN aside.
Step 9
Glue (3M Spray works well) the foil to the backboard starting at the outer edges. A 20mm gap in the center is OK.
Step 10
Find the centers of the dowels and drill pilot holes for the screws in one end of each.
Step 11
Attach the dowels to the backboard at each of the previously drilled holes.
Step 12
Lay one of the wires on top of its support dowels and staple or tack them in place starting at the center. Then the other wire.
Step 13
Place the BALUN in the center hole so that the 75 Ohm connector protrudes from the rear of the board about 13mm.
Step 14
Silicone or hot glue it in place.
Step 15
When the silicone or glue is dry, solder the wires from the BALUN to the center points of the antenna wires on top of the dowels. (Might have to temporarily pull the staple or tack.)
Step 16
Connect 75 Ohm cable between Antenna and TV/DTV converter box.
Step 17
Mount and aim the antenna.
Tips
Warnings
- The original design for the Gray-Hoverman antenna is at http://www.digitalhome.ca/ota/superantenna/index.htm but their drawing didn't include drilling templates, etc.
- The Gray-Hoverman antenna was released under the GPLv3 license, which stipulates that the following text must accompany this article:
- The Gray-Hoverman antenna designs, schematics, and diagrams on this site are Copyright ©2008 and are free: you can redistribute them and/or modify them under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at our option) any later version. These designs, schematics, and diagrams are distributed in the hope that they will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. For your complete copy of the GNU General Public License to go along with the designs, schematics, and diagrams, see www.gnu.org/licenses/gpl.txt
- For outdoor use replace the plywood and foil with a mesh reflector using "corn crib" fencing because this design would have too much wind loading for outdoor use
- Also, the plywood would come apart after being rained on a few times
Things You'll Need
- Backboard: 3/8” or 1/2” plywood, 31” H X 25” W
- About 6 feet of 12-2 Romex or 12 feet of #12 solid wire. Insulated or uninsulated is OK.
- 18 dowels, 1/2” dia, 100mm long. Cut from stock as necessary. 3/4” X 3/4” sticks are OK too.
- 18 #6 X 1&1/4” wood screws or drywall screws to hold dowels to backboard.
- 1 300 Ohm/75 Ohm BALUN (<$5.00 at Radio Shack)
- 6 feet of 12” wide aluminum foil.
- 6 in of solid Cat 5 or phone wire or other 22 to 24ga solid bare for extending the 300 Ohm leads on the BALUN.
- Silicone or hot melt glue.
- Stapler or upholstery tacks. (the little black ultra-sharp ones
- A drill with assorted small bits
