What are long-wire and random-wire antennas?
A long-wire antenna is a single wire at least one wavelength long. As length increases, its main lobes move closer to the wire axis and gain rises slowly; terminating the far end in a resistor makes it a traveling-wave antenna with a unidirectional pattern, as in the Beverage and rhombic antennas.[1][2] A random wire is an arbitrary-length end-fed wire matched with a tuner.[3]
What is the difference between standing-wave and traveling-wave wires?
An unterminated wire reflects current at its open end, creating a standing wave and a bidirectional pattern with lobes symmetric about the wire’s normal. A wire terminated in roughly its characteristic impedance to ground carries a traveling wave and radiates primarily toward the terminated end, with lobes at a small angle to the wire that shrinks as length increases.[1]
What are Beverage and rhombic antennas?
The Beverage, developed by Harold Beverage in the 1920s, is a long wire a few meters above lossy ground terminated at the far end. It is a low-efficiency but highly directional receiving antenna for LF, MF and low HF, where atmospheric noise dominates. The rhombic joins four long wires in a diamond, terminated at the far apex, for high-gain HF point-to-point links.[2][3]
How is a random wire fed?
An end-fed random wire presents widely varying impedance across bands, so it is used with an antenna tuner or unun at the feed point and a counterpoise or ground system. Lengths that are close to multiples of λ/2 on used bands give very high impedances and should be avoided unless a high-impedance transformer is intended, as in the end-fed half-wave.[3]
Frequently asked questions
Is a Beverage a good transmitting antenna?
No; its terminating resistor and ground losses make it inefficient. It is a receiving antenna.
Why do lobes move toward the wire with length?
Phase progression of the traveling current means radiation adds in phase only near the wire direction.
Do long wires need a ground?
End-fed wires need a counterpoise or ground return for the feed current.
See also
References
Online sources accessed October 21, 2026; printed works cited by edition. See all sources.
- “Antenna Theory: Analysis and Design, 4th ed.”. C. A. Balanis, Wiley. 2016.
- “Antennas for All Applications, 3rd ed.”. J. D. Kraus and R. J. Marhefka, McGraw-Hill. 2002.
- “The ARRL Antenna Book for Radio Communications”. ARRL. multiple editions.