Can you really make a ham radio antenna out of a Slinky, the beloved spring toy? Indeed you can, but it needs to be one of the metal models that were produced in the late 1950s and '60s, and have recently been reintroduced. A Slinky is really nothing more than 63 feet of flat steel wire -- plenty of surface to conduct radio waves. The fact that it is wound into a helix gives it additional resonant properties that make it a lightweight, portable antenna. In fact, soldiers in Vietnam prized the Slinky as a radio antenna that could be carried and set up anywhere.
Run the rope through the centre of the two Slinkys, and tie each end to stable objects about 40 feet apart.
Clip the end loop of one Slinky to one end of the rope, using a clothes pin. Stretch the other side of the slinky to within 2 inches of the centre of the rope, and clip it at that point. Do the same thing with the other Slinky on the other side of the rope. You now have the two Slinkys stretched out on either side of a 4-inch gap in the centre of the rope.
Attach the each of the end-terminals on the two coaxial-to-end-terminal cables to an alligator clip, fastening them to the screw on the top of the alligator clips. Slip each end-terminal through the handle in the alligator clip, and pull it up through the slot next to the retaining screw. Wrap the terminal around the retaining screw and tighten it with the appropriate screwdriver (whose type may vary).
Go to the centre gap between the two Slinkys. Clip one alligator clip to the right-hand Slinky and the other to the left-hand Slinky.
Attach the coaxial ends of the two cables to the two coaxial inputs on the antenna tuner.
Connect the antenna tuner to the ham radio with coaxial cable, if it is not already integral to the radio.
Set the Antenna, Transmitter, and Inductance settings on the antenna tuner to the values prescribed by the manufacturer for the band on which you wish to transmit/receive.
This antenna should work on all frequencies from the 7MHz band and up. You can buy kits online with all the pieces you need to build a Slinky antenna, as well as detailed technical instructions for operation.
Broadcasting through this antenna introduces high radio-frequency voltages into the line. Do not allow anyone to touch the Slinkys or the connection lines while the radio is operating. Make sure all equipment and connections are properly grounded. Slinkys corrode quickly when exposed to moisture, so they are not appropriate for permanent outdoor installations.