Radio waves and Microwaves
Radio communications Radio waves are used to broadcast radio or television signals from transmitters, which are then converted into electrical signals with an aerial (which is made out of metal to absorb the radio waves) so you can hear and see them. When done so the aerial converts this wave into an electrical signal (because of the electromagnetic waves energy exciting particles in the aerial and causing them to oscillate/vibrate and thus create an electrical current) this electrical signal is an alternating current which has the same frequency as the radio wave. This electrical energy can again be converted through a loudspeaker into sound, or using a television into light. Also each radio station and television station is given a specific frequency to broadcast at so that when you tune your television or radio you get only one radio station not all of them.

Receiving signalsWe not only send information in radio waves we also use microwaves. They are both absorbed by very thick or dense objects, like hills. However some long wave radio signals can be diffracted around a hill and still reach us to be able to be heard. This only happens to longer wave radio waves that have wavelengths of

around 1000m because the wavelengths are more similar to the sizes of the hills. Therefore because of this even if you live somewhere where there is no line of sight to a radio station you can still receive long wave radio signals, but not microwaves because they cannot be diffracted by hills as their wavelengths are much smaller. Also it is helpful to remember that radio waves can be reflected off the ionosphere and be received in longer distances through that route.

MicrowavesSatellites are used to transmit information very quickly around the world, and they can be used to get information to very hard to reach areas like places that are very remote – the top of Mount Everest. It can also provide a large area of land with...

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...beginning our research
on radiowaves, to us, radiowaves were just
waves going through the atmosphere, carrying
sound from one place to another. Those were our
ignorant days! We did not realize the complicated
terms and theories involved. In the following
report you will see how we advanced in our
knowledge of radiowaves, and we hope it will do
the same for you. Radiowaves are a combination
of two kinds of electric vibrations. Audio
frequency waves, which represent voice and other
sounds and radio frequency waves, which carry
audio waves after being combined with them. Two
examples of broadcast waves are AM waves and
FM waves. AM which stands for amplitude
modulation, is a broadcasting method in which the
carrier waves (carry the sounds of a program) are
changed to match changes in the audio frequency
waves. These are electric waves that represent the
sounds of a radio broadcast. FM stands for
frequency modulation and these waves, that go
skyward, are not reflected. Instead, they pass
through the atmosphere and go into space. AM
signals, however, reflect off the atmosphere and
travel back down to earth, causing broadcasts to
be received at a much greater...

...RadioWaves
In the modern society, radio is the most widely used medium of
broadcasting and electronic communication : it plays a major role in many areas
such as public safety, industrial manufacturing, processing, agriculture,
transportation, entertainment, national defense, space travel, overseas
communication, news reporting and weather forecasting. In radio broadcasts, they
use the radiowaves which can be both microwaves and longer radiowaves. These
are transmitted in two ways: amplitude modulation (AM ) and frequency modulation
( FM ). These two kinds of wave have many differences.
Radiowaves are among the many types of electromagnetic waves that
travel within the electromagnetic spectrum. Radiowaves can be defined by their
frequency (in hertz, after Heinich Hertz , who first produced radiowaves
electronically), which is number of times they pass through a complete cycle per
second; or by their wavelength, which is determined by the distance (by meters)
that is traveled from the crest of one wave to the crest of the next.
Radio frequencies are measured in units called kilohertz, megahertz, and
gigahertz. (1 kilohertz = 1000 hertz : 1 megahertz = 106 hertz, 1 gigahertz =
109 hertz). All...

...﻿MICROWAVERADIO COMMUNICATIONS AND SYSTEM GAIN (c22 Tomasi)
CHAPTER 24
MICROWAVERADIO COMMUNICATIONS AND SYSTEM GAIN
1)Electromagnetic waves with frequencies that range from approximately 500 MHz to 300 GHz or more.
Microwaves
2)The wavelengths for microwave frequencies, which is than infrared energy.
1 cm and 60 cm slightly longer
3)The name given to microwave signals, because of their inherently high frequencies, have short wavelengths.
“Microwave” waves
4)Each frequency is divided in half with the lower half identified as the low band and the upper half as narrow band.
Full-Duplex (Two-way)
5)Communications system used to carry information for relatively short distances such as between cities with the same state.
Short Haul
6)Microwave systems that is used to carry information for relatively long distances, such as interstate and backbone route applications.
Long Haul
7)It propagate signals through Earth’s atmosphere between transmitters and receivers often located on top of tower spaced about 15 miles to 30 miles apart.
MicrowaveRadios
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...﻿Radiowaves for Communication
Radiowaves are electromagnetic waves with wavelengths larger than the infrared light. Like all other electromagnetic waves, they travel at the speed of light. The wavelengths can vary from the size of a football field to the size of a football. They can be produced naturally by large stars and by lightning. Man-made radiowaves are used for transmitting signals and currents.
Specific Properties of Radio Frequency (RF) Current
Radio frequency is the frequency of radiowaves ranging from 3 kHz to 300 GHz. RF current has the following properties:
1. The energy in an RF current can emit back into space in the form of radiowaves. This is the foundation of radio technology.
2. RF current does not penetrate deeply into conductors but flows along the exterior. This is known as skin effect. Due to this, the body gets burnt only on the surface on coming in contact with RF currents. These burns are called RF burns.
3. RF currents do not easily give electric shocks because they change direction too quickly to cause the depolarization of nerves membranes.
4. RF currents can easily ionize air to create a conductive path through it.
5. RF current has the ability to appear to flow through an insulating substance.
6. RF current has a...

...signal) is produced when radio stations broadcast.
A radiowave (radiating electric field) propagates out from the source, traveling at the speed of light. The source, for example an antenna, creates oscillating electric(E)/ magnetic(B) fields. These fields are perpendicular not only to each other but to the direction of the traveling wave, and travel away from the antenna. The electromagnetic wave is, therefore, a transverse wave. The electric/ magnetic fields store the energy of the wave. Basically, the oscillating current to the antennas sets the electrons in motion. These electrons, being accelerated, create discontinuity in the electromagnetic field.
•Briefly explain what is actually producing the radio signal.
Energy, in the form of electromagnetic radiation, exerts steadily oscillating force on charges (electrons). The force is originally exerted strongly in one direction, but then reverses for the cycle to continue. The radiowaves push on the electrons in the metal in the antenna, causing the oscillating up and down the length of the source (antenna). The current is this created in the antenna.
•Adjust the transmitter on the simulator so that it is in the sinusoidal mode and the electrons are oscillating up and down at a regular frequency. Ensure the “display the curve” and the “radiated field” boxes are checked. What...

...Waves Assignment
Microwave Ovens
Microwave ovens, or microwaves, are kitchen appliances which use microwave radiation to cook, heat or defrost food.
Properties of a microwave:
Microwaves are electromagnetic waves with wavelengths longer than those of Terahertz (THz) wavelengths, but relatively short for radiowaves. Microwaves have wavelengths approximately in the range of 30 cm (frequency = 1 GHz) to 1 mm (300 GHz). The word microwave generally refers to "alternating current signals with frequencies between 300 MHz (3 x 108 Hz) and 300 GHz (3 x 1011 Hz)."
History of the microwave oven:
The microwave oven was first invented by Dr. Percy Spencer who was a self taught engineer in 1946. He discovered that a magnetron tube which was a new type of vacuum tube, could melt things.
He conducted an experiment by placing some popcorn kernels near the tube and found that the kernels near the tube cracked and popped. He attributed this result to exposure to low-density microwave energy.
Dr. Spencer created a metal box with an opening into which he fed microwave power, thus creating a higher density electromagnetic field. When food was placed in the box and microwave energy powered up, the temperature of the food rose rapidly.
In...

...unique way by matching the brand personality with that of the Radio channel and altering the channels positioning to accommodate the brand’s requirements. Coupled with the on ground activation and using the brand ambassador so judiciously this was a truly innovative campaign.
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The game of Antakshari lies in the heart of most Indian celebrations and gatherings. Close-up and 92.7 BIG FM decided to bring back Close-up Antakshari on radio and the show became a grand success – it was awarded an RMAI Flame 2013 award for ‘Best Radio Campaign of the Year’. Given the encouraging response received in Uttar Pradesh in 2013, Close-up Antakshari moved to Jharkhand and Bihar.
Renowned actor, singer and music director Manoj Tiwari returns as the host for the 2nd Season. 12 teams from 12 different cities will be selected through a process of city finales, from which Manoj Tiwari will select one team each from UP, Jharkhand; while famous actress Ratan Rajput will choose the winner from Bihar through a process of elimination rounds on radio where, even listeners can vote for their favorite teams. Going by the response for the first season, registrations are expected to pour in by the hundreds out of which the best teams from the cities will compete in the respective city finales. The city winners will then be pitted against each other through a live 6 week...

...﻿SUBCOURSE EDITION SS0130 B
US ARMY SIGNAL CENTER AND FORT GORDON
PRINCIPLES OF RADIOWAVE PROPAGATION (SC:25C)
EDITION DATE: FEBRUARY 2005
PRINCIPLES OF RADIOWAVE PROPAGATION
Subcourse Number SS0130
EDITION B
United States Army Signal Center and Fort Gordon
Fort Gordon, Georgia 30905-5000
10 Credit Hours
Edition Date: February 2005
SUBCOURSE OVERVIEW
This subcourse is designed to teach the principles of radiowave propagation.
The prerequisite for this subcourse is that you are a graduate of the Signal Officer Basic Course or its equivalent.
This subcourse reflects the doctrine which was current at the time it was prepared. In your own work situation, always refer to the latest official publications.
Unless otherwise stated, the masculine gender of singular pronouns is used to refer to both men and women.
TERMINAL LEARNING OBJECTIVE
ACTION: Describe the principles of radiowaves and how they are propagated as ground waves and sky waves.
CONDITION: Given this subcourse.
STANDARD: To demonstrate competence on this task, you must achieve a minimum of 70 percent on the subcourse examination.
i...