Search results
Results From The WOW.Com Content Network
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.
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 ...
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 ...
Similar to a folded dipole, one can add a third wire to get 9× the efficiency, and so on. [2] Although the name is similar to the folded unipole, the two antennas are electrically different: The folded monopole is a much simpler antenna. Discone antenna The discone is a monopole version of a biconical antenna. The name of the antenna describes ...
Tests done by J.S. Belrose (1994) [7] showed that though the conventional T²FD length is close to a full-size 80 meter (3.5–4.0 MHz) antenna, the antenna starts to suffer serious signal loss both on transmit and receive below 10 MHz (30 m), with the 80 meter band signals −10 dB down (90% power loss) from a reference dipole at 10 MHz.
A turnstile antenna, or crossed-dipole antenna, [1] is a radio antenna consisting of a set of two identical dipole antennas mounted at right angles to each other and fed in phase quadrature; the two currents applied to the dipoles are 90° out of phase. [2] [3] The name reflects the notion the antenna looks like a turnstile when mounted ...
Rigorous testing of the loop Yagi–Uda (quad) antenna show the following advantages over a dipole-based Yagi–Uda antenna made from dipoles: [10] Polarization It is easy to change polarization from vertical to horizontal, by changing the feed point. Multiband antenna It is easier to design a multiband quad antenna than a multiband Yagi antenna.
Corner reflector UHF TV antenna from 1954 with bowtie dipole driven element. A corner reflector antenna is a type of directional antenna used at VHF and UHF frequencies. [1] [2] It was invented by John D. Kraus in 1938. [3] [4] It consists of a dipole driven element mounted in front of two flat rectangular reflecting screens joined at an angle ...