Random wire antenna

[2] Further confusing the issue, if an antenna is used over a wide range of frequencies, some writers may technically qualify it as a long wire at the shorter wavelengths but not at the longer.

The term random wire raises no such quibbles: Its only requirement is that the antenna length was not planned for resonance at a particular interesting frequency.

Although antennas an odd numbers of quarter-wavelengths long are easy to feed, when the length of the wire is near an even multiple of a ⁠ 1 / 4 ⁠ wave, its feedpoint impedance may take on thousands of Ohms of both reactance and resistance due to antiresonance – extreme values which can exceed the ranges where conventional impedance matching schemes are adequate.

A folded or zig-zag antenna may exhibit a more complex pattern as there are even fewer symmetry constraints on the dipole moments that may contribute.

[1] One side of the output of the tuner is connected directly to the antenna, without a transmission line, the other to a good earth ground.

[5][6] Even without a good earth, the antenna will still radiate, although poorly; it will do so by capacitively coupling to any nearby conducting material; this is not recommended.

A wire antenna kit, with a coil of wire, strain insulators and a balun . When installed the wire is supported by buildings or trees using the insulators to prevent a short circuit to ground.
A typical permanent wire antenna strung between two buildings and then extended off to a remote post. This example shows a lightning switch on the window frame, to disconnect the radio and ground the antenna for safety during electrical storms.