Introduction: Ehow Outdoor and Indoor DTV Antennas.
Somehow the text for this frame was lost. Anyway I wanted to make my own version of their antenna. Thinking it would be like the (second) picture was a real mistake. NormallyThe third picture I think is the type of antenna the original antenna was intended to duplicate. I would not include such a picture except for clarity. Also included are other pictures of foild antennas we have made. The ehow antenna was made with coat hangers and wood. We wanted somethhing a little safer for indoor use.
Note: I went to look for the original article so I could quote it, but could not find it.:In any case it came from ehow.com. It was similar to this article: http://www.ehow.com/how_7788726_build-vhf-tv-omni-antenna.html
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Step 1: What's Needed.
A drawing of what it might look like.
14-inch long non-coated brazing rods (16)
Metal coat hangers (4)
300 ohm twin lead flat antenna wire 20 inches long
15 by 9 inch cooling racks (4)
Oil based outdoor wood sealer
2 by 3 by 21 inch piece of wood (2)
1 by 2 by 18 inch piece of wood (2)
No. 10 wood screws one inch long (20)
No. 10 wood screws two inches long (8)
No. 10 flat washers (20)
75-ohm VHF/UHF transformer balun
Pliers with wire cutter
Squeeze tube of outdoor weather caulking
Antenna mast or rotor
Thick poster board
Regular poster board
Rolls of aluminium foil.
75-ohm VHF/UHF transformer balun
300 ohm twin lead flat antenna wire 20 inches long
Step 2: Step 1.
Paint with a clean brush all surfaces of the wood with an oil-based wood sealer. Let the wood dry fully overnight.
Note: We are going to use double thick poster board.
Cut the ten pieces of poster board to size. (4 - 2 x 18 and 6 -3 x 21) and can be done with one poster board.
No painting is required, but you will need to glue each of the two/three piece sets together for four separate units. Let dry.
We had some leftover partially unused poster board, so I made 2 extra 2 x 18 sections so all the boards would be the same thickness as the longer units.
Step 3: Step 2.
Cut the twisted hanging section of the coat hangers using the wire cutting section of your pliers. Straighten the remaining piece of each hanger. Using the pliers, bend one end of each of the two straight wires to form a small "U" to fit around the screw. Sand off the coating on the "U" section.
Note: We will be using four twenty one inch strips of folded aluminium foil. Fold them lengthwise till you get thin strips. Take an ohm meter or a continuity tester and make sure the foil conducts electricity. You will have to use something else if it does not.
Step 4: Step 3.
Cut 16 brazing rods down to 14 inches with wire cutters. Bend each piece in half to form a "V" shape with a 3-inch gap at the open end. Each leg of the "V" should measure 7 inches.
Note: Sixteen more fourteen inch foil strips that you will need to fold as in the last step.fold each strip into a vee pattern with a three width between the tines.
Step 5: Step 4.
Place one 2 by 3 by 21 inch piece of wood on a flat surface with the 3-inch wide side facing up. Run your tape measure down the length of wood 1 1/2 inches in from the edge. Place a mark at 2, 8, 14 and 20 inches from the top of the board. Do the same on the opposite edge of the wood.
Note: we will be using a double thick poster board. Also shown are the shorter sections. Notice the difference on the sections I cut with scissors versus using a razor blade.
Step 6: Step 5.
Insert a No. 10 one-inch screw into a washer and screw it halfway into the wood at each of the marks you made.
Note: In our version you will not need to do this. So take a break for a bit and then continue on.
Step 7: Step 6.
Slide the bent "U" shape end of one of the wires under the washer of the top left-hand screw. Run the straight wire down the length of the wood touching the screws on the left side. Slide one "V"-shaped brazing rod under the washer. Tighten the screw with the open end of the "V"-shaped rod pointing straight out from the wood on the left side. Do the same for the top right-hand screw.
Note: we will tape down the "V"-shaped rod pointing straight out from each of the points we have marked. we will tape down the tines instead of using screws at the focal point.
Idea: If I had to do it over again, i would just cut out the pieces form a foil tine and just fold them over. That is sturdier, quickerm and therfore easier.
Step 8: Step 7.
Cross the two straight wires over to the opposite side of the wood. Slide the wires under the washers of the second and third set of screws from the top. Slide a "V"-shaped rod under each washer. Tighten the screws, keeping the open end of the "V"-shaped rod facing straight out from the wood.
Note: be sure not to let the two foil sections touch where they cross. We liberally used tapeto make sure there would be no contact.
Step 9: Step 9.
Separate with your fingers the wire where it crosses the other wire. Put a small amount of caulking on the bottom wire where it will touch the upper wire. Slide a pencil between the two wires to let the caulking dry for a bit. Do the same for the second wire crossing. These wires should not touch each other.
Note we have already used the tape to accomplish this. You could use an ohm meter to make sure their is no connection.
Step 10: Step 10.
Sand a one-inch section of the straight wire's midpoint between screw No. 2 and No. 3. Screw a washer loosely into position over the sanded section of wire. Make a 2-inch cut with a knife at each end of the flat section of the 300-ohm wire. Spread the ends apart. Strip one inch of wire coating with your wire strippers. Attach one wire of the 75-ohm VHF/UHF transformer balun (cable adapter) to the screw under the washer and one of the 300-ohm wires and tighten the screw. Do the same for the other side using the second wire from the balun and 300-ohm wire.
Note: tape down the balun. Balun should not be touching the foil.
Step 11: Step 11.
Repeat these steps with the remaining parts to make a second antenna. Do not attach a second balun to the second antenna section. Screw in the screws but don't connect anything to them yet on the second section.
Note: Attach the wire and tape down.
Step 12: Step 12.
Turn the antenna over and screw two 15- by 9-inch cooling racks (reflectors) to the wood. One rack will line up with the top two bow ties and the other with the bottom two bow ties. Do the same with the other antenna section using the last two cooling racks.
Note: Cut 4 pieces of poster board and 4 pieces of foil nine by fifteen inches. If you can not get foil the right size, cut additional pieces to fit. Glue the foil to the poster board with the shiny side away from the poster board. Let dry!! Optional: Cut long strips from the unit so that it looks like a grill. Glue the spacers to the back of the three by twenty one inch units. Let dry. Glue the units you have made to the spacers arranged as above.
Could not find any 9 x 15 cooling racks. but the ones from the dollar store probably would have worked good enough.
Step 13: Step 0d.
Place both antennas with the reflectors facing up side by side. Line up the open edges of the "V"-shaped brazing rods with the tips of the rod one inch apart from the other antenna. The antenna should look like a square.
Note: We will lay ours face down to make glueing the cross members easier and then set for one inch apart.
Step 14: Step 14.
Place a 1 - 2 by 18-inch piece of wood across the top section of the two antennas joining them. Place the second piece across the bottom to make a square frame. Screw the frame together with No. 10 two-inch screws.
Note: Glue the four pieces into place. Let dry. (To be honest, I used some wood screws to make it a bit more stable.)
Step 15: Step 15.
Turn the antenna over and connect the other end of the 300-ohm flat wire to the screw connectors on the second antenna. Tighten the screws. Remove the pencils from the crossing wires.
Note: tape the flat wire to the same corresponding part of the foil on the other half of the antenna. At the making of the this instructable with did not have any 300 ohm wire yet.
Step 16: Step 16.
Squeeze some caulking over the screw connections to protect them from the weather. Attach the antenna to the mast or rotor on the center of the cross supports using screws. Connect the cable from the TV and you are finished.
Note: Just connect the cable from the tv. (The microsphone stand ends up getting another use. Need to make a second on for the antenna.)
Step 17: Addendum:
Looking for a better safe way to allow the foil tines to stay straight. Will come out with an update when I do.
Optional variation of the antenna. Actually that is what I thought the antenna might look like before reading though all the steps completely.