Hobbies And Interests
Modified Cubial Quad Antenna
The modified cubial antenna is a simple indoor aerial project. Put two dowels made of wood or some other material that does not conduct electricity together in an "X" shape, with 90-degree angles between the sticks. Attach with string, tape or tacks. Cut slots in the outer ends of each stick, and wrap insulated wire around the outside spokes, forming a square of wire. Secure the wire at each spoke and hold it taut using electrical tape or cable ties. At the last spoke, pull the wire taut and extend each side of the wire an inch or so past the spoke. Cut the wire and strip the insulation from the ends. Strip the insulation from the two wires of a 300 Ohm ribbon feeder cable and attach one to each of the wires on the antenna. Attach the antenna to the radio receiver using the ribbon cable.
Modification for Coaxial
For a receiver that uses a coaxial connection for the antenna, on the final step of the cubial antenna, attach a coaxial cable rather than the ribbon wire. Strip the ends of the insulated wire and the end of the coaxial cable. If there is a connector at the end of the coaxial cable, cut it off, then strip the wire. Attach one wire to the center conductor in the coaxial cable and the other wire to the outer shield wire. Twist them together and solder if possible.
Simple Wire
Just a length of 300 Ohm twinlead wire can make an FM aerial with solid performance. The wire is available from electronics suppliers at a fairly low cost. Calculate the ideal length for the antenna based on the frequency you want to target. For the broad FM spectrum, use 98 Mhz, the central frequency on the FM band. The ideal length for an FM aerial is multiple of 5/8th the wavelength you are targeting, so to get the ideal length of wire, multiply the wavelength by 5/8. For electronic reasons, this length amplifies the signal the most. Pin the wire high onto the wall, at the ceiling or in the attic for best reception. Use another length of twinlead wire to connect the aerial to the FM receiver.
Moxon Indoor FM Antenna
There are many versions of a Moxon antenna, which is a rectangular FM antenna. You can make an indoor Moxon antenna out of PVC pipe available at any home improvement store. Make a rectangular PVC frame using two two-foot lengths of PVC and two three-foot lengths connected by 90-degree elbows at the corners. Run insulated wire around the rectangle, and leave three gaps in the wire. Use zip ties to connect the gaps and keep the wires taut. The Moxon antenna has a driven portion and a reflector portion. The gaps separate the two portions, allowing the antenna to pick up signals. Create a stand that is at least as tall as half a wave-length of the lowest frequency you'll want to bring in. Use four one-foot pieces of PVC connected with 90-degree elbows to make a square base, then add a cross piece through the center. In the cross piece, add two "T" PVC connectors to hold the PVC uprights, then attach the rectangular antenna on the top of the uprights.