fm radio antenna

The radio horizon for space waves is about four-thirds as far as the optical horizon. This beneficial effect is caused by the varying density of the atmosphere, and because of diffraction around the curvature of the Earth. The radio horizon of an antenna is given, with..

Let us now discuss the basic principles of wireless radio communications. We shall mainly concentrate on the principle of amplitude modulation and demodulation. The simplest scheme of wireless communication would be to convert the speech or music to be transmitted to electric signals usin..

The amplitude-modulated band (AM band) contains the radio waves having frequency of less than 30 MHz or having wavelength of 10 m or more. The lower atmosphere is more or less transparent to radio waves. However, the ionosphere reflects back the radio waves. Thus, a s..

. A good quality service can be continuously ensured by a global operational satellite system. Thus, communication satellites would give a valuable service in addition to the submarine cable and high frequency radio systems. Geostationary communication satellites have enabled not only nat..

(i) Various electrical machines and noises cause amplitude disturbance in the transmission of amplitude-modulated wave. This makes the reception noisy. So, there is a need for different type of modulation, which can reduce the noise factor. Frequency modulation (FM) was proposed as a mean..

Any tall or massive objects will obstruct space waves, since they travel close to the ground. Consequently, shadow zones and diffraction will result. This is the reason for the need in some areas for antennas higher than would be indicated by Equation (1). On the other hand, some areas re..

The AM radio waves which propagate from one point to another following the surface of Earth are known as ground waves or surface waves. This type of propagation is called ground wave propagation or surface wave propagation. In ground wave transmission, the intensity of the signal falls w..

>This frequency for which the current in AC circuit reaches a peak value and the A.C circuit behaves like a pure resistive circuit is called resonant frequency. The following diagram shows the variation of frequency with I o . Notice that as the value of R decreases, the value of I o increases. Sin..