أنواع وقياسات الهوائي ثنائي القطب المطوي .. كتاب التلفزيون الملون والعادي

Types and measurements of folded dipole antenna:

It is called the folded dipole, and it is made of aluminum tube and its length after being folded (as in the figure) is equal to half the wavelength of 0.95x. Its two open ends, Figure 4, are connected to the simplified or coaxial antenna cable, depending on the entrance impedance of the television set, and it is connected directly to the cable or to an impedance compatible transformer.

A reflective pole is placed behind the dipole whose length exceeds the dipole by (5%) and is away from it by (15) to 20% of the wavelength. pole before it. It is 18% away from the wavelength. The number of routers may reach from (5-13) routers. The impedance of the folded diode is about 300 ohms. Figures (4 - 8) (4) - (9) - (4 - 10)
​​​​​​(4-11) Different types of antennas appear, and from that we find that the length of the dipole is proportional to the wavelength of the channel, and that reflectors and routers increase the gain of the antenna and improve its directionality. The most commonly used antenna is the dipole type (bagee). It is known that calculating the wavelength in meters is equal to = 300,000,000 at the frequency of the wave in hertz