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2. G5RV antenna - Wikipedia

   en.wikipedia.org/wiki/G5RV_antenna

   A transmatch (antenna tuner) is not required to use this antenna near its nominal design frequency of 14 MHz, and judicious length adjustments can sometimes include one other frequency band. All other frequencies require a transmatch. [citation needed] There are many variants of the G5RV antenna. Two variations of the G5RV design, called ZS6BKW ...

3. Dipole antenna - Wikipedia

   en.wikipedia.org/wiki/Dipole_antenna

   A half-wave dipole antenna consists of two quarter-wavelength conductors placed end to end for a total length of approximately ℓ = ⁠ 1 / 2 ⁠ λ. The current distribution is that of a standing wave , approximately sinusoidal along the length of the dipole, with a node at each end and an antinode (peak current) at the center (feedpoint ...

4. Beverage antenna - Wikipedia

   en.wikipedia.org/wiki/Beverage_antenna

   The AT&T receiving Beverage antenna (left) and radio receiver (right) at Houlton, Maine, used for transatlantic telephone calls, from a 1920s magazine. The Beverage antenna or "wave antenna" is a long-wire receiving antenna mainly used in the low frequency and medium frequency radio bands, invented by Harold H. Beverage in 1921. [1]

5. Electrical length - Wikipedia

   en.wikipedia.org/wiki/Electrical_length

   As the length of an antenna is made shorter than its fundamental resonant length (a half-wavelength for a dipole antenna and a quarter-wavelength for a monopole), the radiation resistance the antenna presents to the feedline decreases with the square of the electrical length, that is the ratio of physical length to wavelength, (/). As a result ...

6. Monopole antenna - Wikipedia

   en.wikipedia.org/wiki/Monopole_antenna

   Since a half-wave dipole has a gain of 2.19 dBi and a radiation resistance of 73 Ohms, a quarter-wave (⁠ 1 / 4 ⁠ λ) monopole will have a gain of 2.19 + 3.0 = 5.2 dBi and a radiation resistance of about 36.5 Ohms. [13] The antenna is resonant at this length, so its input impedance is purely resistive.

7. Sloper antenna - Wikipedia

   en.wikipedia.org/wiki/Sloper_Antenna

   The angle of the slope is usually between 45°–60° and the lower end of the wire is at least 1 ⁄ 6 wavelength above the electrical ground. [3] A sloper is typically fed with a coaxial cable in the center, at the top of the center support mast. At least 1 ⁄ 4 of the wavelength of feedline must be at 90° angle to the antenna. [3]

8. Loop antenna - Wikipedia

   en.wikipedia.org/wiki/Loop_antenna

   Typical feeder loops are ⁠ 1 / 8 ⁠ to ⁠ 1 / 5 ⁠ the size of the antenna's main loop, which gives transform ratios of 64:1 to 25:1, respectively. Adjusting the proximity and angle of the feeder loop to the main loop, and distorting the feeder's shape, both make small-to-moderate changes to the transform ratio, and allows for fine ...

9. Antenna measurement - Wikipedia

   en.wikipedia.org/wiki/Antenna_measurement

   Antenna directivity is the ratio of maximum radiation intensity (power per unit surface) radiated by the antenna in the maximum direction divided by the intensity radiated by a hypothetical isotropic antenna radiating the same total power as that antenna. For example, a hypothetical antenna which had a radiated pattern of a hemisphere (1/2 ...