What are the different types of UHF antennas?
Ultra high frequency antenna (UHF), more often called UHF antenna, can come in many different forms for use with electronic devices that receive or transfer radio signals between 300 Megahertz (MHz) and three Gigahertz (GHz). This type of antenna can come in almost any shape or size, but falls into one of several categories of antennas: antenna quarter wave, half wave dipole antenna, folded dipole antenna, loop antennas and Yagi antenna. Each has advantages and disadvantages.
The quarterly wave of UHF antenna, commonly called the "whip" antenna, consists of a single metal rod or wire that is a quarter of a wavelength that is long. They are usually mounted vertically, similar to the types of antennas observed on cars. As a result, it is said that they are "vertically polarized", with one pole in the top of the antenna and the other at the bottom. Most UHF transmitters are horizontally polarized and UHF aircraft antennas are the least effective from the antenna antenna antennaas; OneThe ghost of the design, easy connection to equipment and the ability to receive signals from any direction or omniiformly, but often prevails over this deficiency.
Several quarterly wave antenna antenna connects the antenna wire to appear as a long spring. Although the antenna is still vertically oriented and polarized, horizontal aspects of individual coil windings can improve the efficiency of the antenna. Despite this improvement, the fourth wave aircraft antennas are usually used only in a device where the costs, portability and need to receive signals from all directions are paramount.
Antenna half of the UHF dipole, the standard in the UHF antenna, consists of two metal bars or wires that spread straight, usually horizontally, with one end of the other. These two components consist of half of the wavelength to be accepted for a long time. Though Half Wave UHF antennas are more efficient nTheir cousins a quarter of a wave, gain only good signals that hit two elements of the antenna perpendicularly, requires these antennas to point to the signals they are to receive. Because the standard UHF air antenna, half wave dipoles are often integrated into other, more efficient UHF antennas designs.
Porad dipole antennas are very common. This type of UHF antenna is made of a single piece of metal or wire folded or bent into a shape that approaches two ends together. In this way, they act as a half -wave dipole antenna and have almost identical properties, although they tend to be less effective. The main advantage of compound dipole antennas is that they are easy to make of cheap materials. Antenna antenna antenna type loop type, often used with television, is an example of a composite dipole antenna.
Despite the name, the loop antennas are not the same as the round roller of the loop used as a television antenna. Instead, the loop antennas consist of a lot of wire lengthtimes around the ferrite core, usually only a few inches long. These antennas have good revenue properties, but are not completely versatile. The loop, which is often called the "sticks" antennas, are most often the inner antennas hidden inside cases of an electronic device.
TheYagi antennas consist of metal bars arranged in parallel with each other and are commonly considered to serve as roof television antennas. Yagi metal rods serve three different purposes. One pair of rods is actually half the wave dipole antenna. Behind the dipole is one to three pairs of bars, which serve as reflectors that broadcast signals that have undergone a dipole back to the dipole. Before the dipole, there are pairs of rods called directors who drive incoming signals to focus on the dipole.
antennas are extremely efficient and are often used where UHF Signals are very weak. They have a significant disadvantage: they are extremely directional and are often able to receive signals in a 20 -level beam. Yagi antennas have timeThe engine that rotates them in different directions because they can "see" stations or transmitters that are directed almost directly at.