WHAT IS AN ANTENNA??

WHAT IS AN ANTENNA??

• Radiating/Receiving element

• Reciprocity - Behave similarly while radiating or receiving

• Isotropic antenna - radiates uniformly in all directions

• In practice, no antenna is isotropic

TYPES OF ANTENNA

• Guyed mast

• ‘T’,k,l and ‘L’ antennae

• Shunt fed

• Top fed

IMPORTANT PARTS

• Base insulator

• cricket ball

• Guy wires

• Guy insulators

• Guy chokes

• Aviation obstruction lighting

• Lighting transformer

• Static leak choke

• Earth radials


RF Cables

• RF cables are generally pressurised and has a characteristic impedance of 50 ohms

• They are available in different sizes and lengths

• They are to be supported and secured for preventing damages

• Cable ends are to be sealed properly to prevent intrusion of moisture

ROLE OF RADIO IN COMMUNICTION

• INFORAMATION TO WIDER AREA

• MESSAGE CONVEYED TO GROUP AT A TIME

• VAREITY OF INFORMATION

• WITHOUT AFFECTING THE DAY TO DAY ACTIVITY OF A PERSON THE INFORMATION IS CONVEYED

• PERSON AT THE RECEPTION CAN CHOOSE HIS REXEIVER AT THIS RANGE(COST EFFECTIVE)

• OBJECTIVE IS TO INFORM,EDUCATE AND ENTERTAIN THE MASSES

Dynamic voltage restorer (DVR)

Abstract
This paper describes the mitigation of voltage sag by using custom power devices. One of custom devices is Dynamic Voltage Restorer(DVR) through which the power quality problems are being studied. As voltage restoration process involves real power injection into the distributed feeder, the capability of a particular DVR topology, especially for compensating voltage sag for long duration that depends upon the energy storage of the DVR. Different solutions have been developed to protect sensitive loads against such disturbances but the DVR is considered to be the most efficient and effective solutions. Since it includes lower cost, small size and its dynamic response to the disturbance. The simulation results were presented to illustrate and understand the performance of DVR under voltage sag conditions.