How Radio Waves Work

TITLE

How Radio Waves Work

INTRODUCTION

This paper is about radio waves and the discovery of it. This paper was complete in partial fulfillment of the course requirements of NASC 2100 as assigned by our instructor at Shorter College, Professor Joe B. Campbell.

MATERIALS AND METHODS

I went to the East Marrietta branch library to find the book The Age of Electronic Messages. I searched the Google internet database for How Stuff Works about Radio Spectrum I also researched Wikipedia for detailed information on Heinrich Hertz. I also searched the Galileo search engine, but did find anything that I could use for this paper.

RESULTS AND DISCUSSIONS

Heinrich Hertz was a student of Dr. Herman von Helmholtz. Hertz was fascinated with the meteorology and found himself occupied with the theory of electromagnetic. In 1864, James Maxwell had a theory of electromagnetic waves being transmitted by sparks. In 1886, Heinrich Hertz proved that electricity can be transmitted in electromagnetic waves while at the University of Kiel. Hertz made a simple receiver with loop wire, and at the ends of the loop were small knobs separated by a tiny gap. Then the receiver was placed several yards from the oscillator. When Hertz turned on the oscillator this was the first transmission and reception of electromagnetic waves. Hertz also developed a dipole antenna. This antenna was an element used for transmitting or receiving radio frequency energy. He was known for being the first to broadcast and receive radio waves. His name also became the term used for radio and electrical frequencies: hertz (Hz). A frequency of 1 Hz means there is one cycle or oscillation per second. We now use the terms Kilohertz (kHz), or thousands of cycles per second, megahertz (mHz), or millions of cycles per second, and gigahertz (gHz), or billions of cycles per second all the time. Dr. Lee deforest was known as the father of American Radio. Dr. deforest invented the three-element electron tube, called the audion. This "triode" tube could amplify signals and generate oscillation, making it possible to transmit sound over wireless communication systems. The first radio AM (amplitude modulation) broadcast began in 1906. A radio wave is one type of electromagnetic radiation, a form of energy that travels in waves. He generated a signal of 75mHz which was picked up from a transmitter. Radio astronomy has an advantage in that sunlight, clouds, and rain do not affect observation. (hsw/radio). In 1915, speech was first transmitted across the continent from New York City, NY to San Francisco, CA, and across the Atlantic Ocean. In 1920, the United States had the first commercial radio broadcast of speech and music. In the late 1930's, all radio stations were AM. The combination of radio and satellite has solved the problems of mathematics and science. Radio navigation systems have been used since the 1940's. Radio signals from space are faint because they need to be amplified by large radio dish antennae. The first sounds transmitted from outer space were "beeps" from the Russian Sputnik on October 4, 1957.The electronic circuitry on the satellite is called a transponder. It receives the signal transmitted from the earth station, the signal is amplified, changed in frequency and retransmitted back to earth.(jgnellist),(p.59) The size and shape of the satellite's radio beam on the surface of the earth is called the "footprint". The antenna design and transmitting power are important to determine the size of the footprint.

Long time ago you could use 9 volt battery and a coin to create radio waves to an AM radio. The transmitter is an electronic oscillator that gives voltage according to a particular frequency. This voltage is applied to the bottom of a vertical metallic rod (antenna). A radio wave is intercepted by the antenna, which coverts the wave into an electrical signal that is transmitted to a radio. Within the radio the electrical signal is converted to a sound wave that can be broadcast through speakers. Music and speech signals are made up of different audio frequencies from 30Hz to 18,000 Hz. In 1992, there were at least 18 satellites in orbit, about 12,000 miles from earth. Each broadcast starts in a precise, prearranged time of schedule. Each satellite sends out 2 radio signals (one at 1,227.60 MHz and one at 1,572.42 MHz with a coded message describing its location. Since the quickness of radio signals is 186,000 miles per second, the receiving equipment can determine the distance from the satellite to the user. Once the user has received the signal from one satellite and calculated the distance from that satellite. Then the user must be located somewhere on a sphere. A Very Large Array (VLA) is on the world's premier

astronomical radio observatories. It consist of a least 27 antennas in a huge "Y" pattern