Make a homemade AM radio antenna by creating a loop of thin gauge insulated copper wire around an object used as a holder and attaching each end of the wire to the radio's antenna leads. A larger loop and more wire increases the range.
A simple version can be made from cardboard by cutting out two pieces about 3 squares inches each with a pair of scissors. Into each piece, cut one slit from the outside edge to the middle. Fit the slits together until the two pieces become flush together and form a cross. This serves as your spindle. Wrap about 4 feet of 16-gauge wire around the cross snugly, leaving about 2 feet at each end to allow your antenna leads to attach to the radio after they have been stripped back about 1 inch. The wire can touch itself in the loops, but having an even gap between the rounds provides better results.
Make a larger version by nailing two 1-by-2-inch boards spanning 17 inches long together in the shape of a cross. Put a nail out at the end of each board to make a larger spindle, and wrap with wire in a similar fashion. You can nail the assembly to a 2-by-4-inch board about 2 feet long and use it to stand up the antenna for better reception.