Search results
Results From The WOW.Com Content Network
A 20-meter-long T²FD antenna, covering the 5-30 MHz band. The Tilted Terminated Folded Dipole (T²FD, T2FD, or TTFD) or Balanced Termination, Folded Dipole (BTFD) - also known as W3HH antenna - is a general-purpose shortwave antenna developed in the late 1940s by the United States Navy.
A folded dipole is, technically, a folded full-wave loop antenna, where the loop has been bent at opposing ends and squashed into two parallel wires in a flat line. Although the broad bandwidth, high feedpoint impedance, and high efficiency are characteristics more similar to a full loop antenna, the folded dipole's radiation pattern is more ...
AT&T 2 wire rhombic in Dixon, California, in 1937, used for telephone service to Shanghai, China. The rhombic antenna was designed in 1931 by Edmond Bruce [1] and Harald Friis, [2] [3] It was mostly commonly used in the high frequency (HF) or shortwave band as a broadband directional antenna.
The two-wire version is often described as a "squashed loop antenna", since the total length of wire is one wavelength, and efficiency / radiation resistance of the folded dipole is very high: 4× that of a single dipole, [citation needed] analogous to the high efficiency of large loops. Any number of similar parallel wires may be added, with ...
The 1 / 2 λ dipole and the 1 / 2 λ folded dipole are commonly taken as having nominal impedances of 75 Ω and 300 Ω, respectively. [ 13 ] An installed antenna's feed-point impedance varies above and below the quoted value, depending on its installation height above the ground and the electrical properties of the surrounding ...
Yagi antenna with one driven element (A) called a folded dipole, and 5 parasitic elements: one reflector (B) and 4 directors (C). The feed line leading to the receiver is not shown; it attaches to the driven element at D. The antenna radiates radio waves in a beam toward the right.
terminated coaxial cage monopole The TC²M is a vertical polarized broadband shortwave antenna. The antenna can be characterized by being a vertical traveling-wave coaxially caged monopole over a ground plane, or alternatively described as a folded unipole with a terminating resistor. [5] off-center fed dipole antennas
Consider a Yagi–Uda consisting of a reflector, driven element, and a single director as shown here. The driven element is typically a 1 ⁄ 2 λ dipole or folded dipole and is the only member of the structure that is directly excited (electrically connected to the feedline). All the other elements are considered parasitic. That is, they ...