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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.
The nominal "80 meter" band begins at 3.5 MHz (85.7 m wavelength) and goes up to 4.0 MHz (74.9 m wavelength).The upper part of the band, mostly used for voice, is often referred to as 75 meters, since in Region 2, the wavelengths in that section are between 80–75 meters (adjacent to or overlapping a shortwave broadcast band called by the same name: "75 m").
The full wave loop (left) emits maximum power broadside to the wires with nulls off the sides, the small loop (right) emits maximum power in the plane of its wires with nulls broadside to the wires. Surprisingly, the radiation and receiving pattern of a small loop is perpendicular to that of a large self resonant loop (whose perimeter is close ...
Half-loop the upper half of a vertical full-wavelength loop antenna mounted on the ground (not to be confused with the visually similar but electrically different half-square antenna described below, under array antennas, [u] nor to be confused with the halo antenna, described next). The full loop is cut at two opposite points along its ...
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 ...
A half wave whip antenna (length of ) has somewhat higher gain than a quarter wave whip, but it has a current node at its feedpoint at the base of the rod so it has very high input impedance. If it was infinitely thin the antenna would have an infinite input impedance, but the finite width gives typical, practical half wave whips an impedance ...
The quarter-wave monopole, the most compact resonant antenna, may be the most widely used antenna in the world. The five-eighth wave monopole – length 0.625 λ , or 5 / 8 of a wavelength – is also popular, since at that length monopoles direct the greatest proportion of their radiated power horizontally, hence the best use of ...
Log-periodic antennas are arrays invented in 1952 and commonly seen as TV antennas. This was long before Mandelbrot coined the word fractal in 1975. [4] Some authors (for instance Cohen) [5] consider log-periodic antennas to be an early form of fractal antenna due to their infinite self similarity at all scales.