Building a radio satellite antenna at home is a popular project. The portable fabric Yagi antenna designed by Diana Eng adapts well. Keeping to the original design of the transmitting and receiving elements, a plastic telescopic poster tube is a simpler alternative to using fabric and a ruler as the backbone of the antenna. The tube also doubles as a storage container when the antenna is not being used. Generally, as long as the shape and size of the elements and their positions relative to each other are maintained, the materials forming the backbone can vary.
- Skill level:
Things you need
- Telescopic poster tube
- 1/8-inch diameter brass rod
- 1/4-inch diameter
- RG-58 coaxial cable
- Coaxial cutters
- Soldering iron
- Black marker
- White out
- 42-inch felt strip
- Broom handle
Compress the poster tube to 26 inches, and remove the cap.
Make small markings with the black marker or white out, depending upon which is more visible, along the tube's length at 8, 15, 18, 20-1/2, and 23-1/2 inches from the bottom end of the tube.
Mark the opposite side of the tube directly across from the marks that you made in Step 2.
Create 1/8-inch holes by puncturing the tube with an 1/8-inch diameter nail at the 18, 20-1/2, and 23-1/2 inch markings . Tap with a hammer to drive the nail through the tube. Remove the nail after making a hole.
Create 1/4-inch holes in the tube by puncturing the tube with a 1/4-inch diameter nail at the eight inch and 15-inch marks. Tap with a hammer to drive the nail through the tube. Remove the nail after making a hole.
Cut an 1/8-inch diameter 6-foot length of brass rod with the hacksaw into segments of 12-1/5, 13-1/2 and 21 inches.
Bend the 21-inch brass rod around the broom handle in the shape of the letter 'J', with the shorter side seven inches in length, and the longer side 13 inches. The length of the 'J' curve should be one inch. Use a vice or a friend to hold the broom handle steady while you bend the rod.
Cut a 9-foot hollow rod into segments lengths of 40-1/2 and 59-1/4 inches.
Bend the 59-1/4 inch segment around the broom handle in the shape of the letter 'J', with shorter side 18-1/2 inches in length, and the longer 39-3/4 inches. The length of the 'J' curve should be one inch. Use a vice or a friend to hold the broom handle steady while you bend the rod.
Prepare the coaxial cable. Cut it in half. Remove two inches of outer insulation from the end of the cable using the coax cable cutter. You will have two inches of exposed copper wire at the end of each piece of coaxial cable. Unbraid the exposed length of outer wiring at the end of each coax cable. Do this by scoring the outer braid with a nail.
Pull all the frayed wire to one side, and twist it together for each of the two pieces of cable. Bend the twisted wire strands perpendicular to the insulator.
Attach one of the coax cables to the J-shaped 21-inch brass rod by wrapping the inner exposed coax cable wire around the leg on the shorter side 1-1/4 inches away from the tip and then wrap the outer exposed wire around the leg directly opposite on the longer side. Solder each of these wires on with the soldering iron.
Attach one of the coax cables to the bent 59-1/4 inch solid brass rod by wrapping the inner exposed coax cable wire around the leg on the shorter side a 1/2 inch away from the tip and then wrap the outer exposed wire around the leg directly opposite on the longer side. and then solder each piece of wire on with the soldering iron.
Write down the length of the curve for each J-shaped rod. Label the distance for the shorter rod " "distance A"; label the longer one "distance B" Note that these distances should ideally measure approximately one inch.
Make a mark with a marker on the poster tube a distance equal to the value called "distance A" above the hole located 20-1/2 inches at this point from the bottom of the tube; make an 1/8 inch hole using the 1/8 inch nail at this point.
Make a mark with a marker on the poster tube a distance equal to the value called "distance B" above the hole located 15 inches from the bottom of the tube; make a 1/4-inch hole using the 1/4-inch nail at this point.
Insert the 40-1/2 inch hollow rod through the hole at the eight-inch mark from the bottom.
Insert the long leg of the bent 59-1/4 inch J-shaped rod through the hole at the 15-inch mark from the tube bottom, and fit the shorter leg in the hole one inch above.
Insert the 13-1/2 inch rod through the hole at the 18 inch mark from the bottom of the tube.
Insert the long length of the 21-inch J-shaped rod through the hole located 20-1/2 inches from the tube bottom, and fit the shorter leg in the hole one inch above.
Insert the 12-1/2 inch rod through the hole located 23-1/2 inches from the bottom of the tube, and screw the cap back on the tube.
Attach the coaxial cable connectors to the RF connectors on your radio.
Slide the rods out of their holes.
Bundle the rods together, and wrap them with the felt fabric.
Extend the tube to its full length, approximately 42 inches, and insert the bundle of rods.
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