- published: 11 Mar 2009
- views: 917357
AM broadcasting is the process of radio broadcasting using amplitude modulation (AM). AM was the first method of impressing sound on a radio signal and is still widely used today. Commercial and public AM broadcasting is authorized in the medium wave band worldwide, and also in parts of the longwave and shortwave bands. Radio broadcasting was made possible by the invention of the amplifying vacuum tube, the Audion (triode), by Lee de Forest in 1906, which led to the development of inexpensive vacuum tube AM radio receivers and transmitters during World War I. Commercial AM broadcasting developed from amateur broadcasts around 1920, and was the only commercially important form of radio broadcasting until FM broadcasting began after World War II. This period is known as the "Golden Age of Radio". Today, AM competes with FM, as well as with various digital radio broadcasting services distributed from terrestrial and satellite transmitters. In many countries the higher levels of interference experienced with AM transmission have caused AM broadcasters to specialize in news, sports and talk radio, leaving transmission of music mainly to FM and digital broadcasters.
Radio is the use of radio waves is to carry information, such as sound, by systematically modulating some property of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.
Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation). Radio systems also need an antenna to convert electric currents into radio waves, and vice versa. An antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected. The electromagnetic wave is intercepted by a tuned receiving antenna. A radio receiver receives its input from an antenna and converts it into a form usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc. Radio frequencies occupy the range from a 3 kHz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum.
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Genres: Comedy, Drama, Sci-Fi,AM & FM radio have been around since way before the digital age. How can radios decode AM & FM signals only using analog technology? Freshbooks message: Head over to http://freshbooks.com/techquickie and don’t forget to enter Tech Quickie in the “How Did You Hear About Us” section when signing up for your free trial. Follow: http://twitter.com/linustech Join the community: http://linustechtips.com
How to make an AM radio transmitter for use with a crystal radio or a normal AM radio. This simple circuit uses an oscillator chip and a transformer to take input from a sound source and turn it into radio waves, transmitted using an antenna. I test it with a CD player as the sound source but it may also work with an iPod or iPhone, though it may need some amplification for that. WARNING: Do not transmit more than 1 or 2 meters/yards otherwise you'll interfere with other radios. For how to make the homemade crystal radio, watch "How to Make/Build a Crystal Radio": http://youtu.be/VqdcU9ULAlA For how to make the crystal earpiece watch "Make Crystal Earphone/Earpiece for Crystal Radio - Homemade": http://youtu.be/OVapqz4yBCY For how to make a lifter or ionocraft, watch "How to Make a Lif...
The technology of amplitude modulation (AM) radio transmission was developed during the two decades from 1900 to 1920. Before this, the first radios transmitted information by wireless telegraphy, in which the radio signal didn't carry audio (sound) but was switched on and off to create pulses that carried text messages in Morse code. This was used for private person-to-person traffic, similar to telegrams. The first AM radio transmission took place in 1906 from a garage in Brant Rock, Massachusetts. After six years of hard work, Reginald Fessenden, a Canadian inventor transmitted the world's first voice message by using an Alexanderson alternator and a rotary spark-gap transmitter. His message was heard by radio-equipped ships within a range of several hundred miles away from the transmi...
Hobo Rishayan shows how you can recieve great AM radio reception from anywhere using just 15 or 20 feet of random hook up wire, on any small portable AM reciever. Used in the demonstration is a Grundig G8 radio which can be found on the internet for around 50 dollars US or so. I bought mine for this price from Microcenter in Houston, but I haven't been able to bring up their website, so maybe they're out of business. But you can get it directly from Eton for 59.99. Amazon has the same radio for well over 100 dollars, which is absurd.
This video covers the history of the discovery of radio waves, to the creation of simple oscillator based radio transmitters. Then I explain what modulation and amplitude modulation are, and show you how to build a low powered AM radio transmitter. My webpage: http://www.afrotechmods.com Original design by Stefan0719: http://www.youtube.com/watch?v=f42W9jNHMZ0 Kickass music by imeddy: http://www.youtube.com/watch?v=MzptQ4ZuTTI
Oldies on am radio -
Scooter - 4 Am (Radio Version) [1 Hour Loop]
Scooter - 4 AM (Radio Edit) [1 Hour Loop]
(Lyrics: Scott Starr)
All I ever do is fall asleep with A.M. radio on.
All I ever hear is static from you.
It makes me feel so out of tune.
You call my faith.
I call this design.
When channels change I feel our receptions out of line.
All I ever knew from reading the signs with A.M. radio on.
All I ever see are visions of you.
You keep my heart constantly moving.
You call my fate.
Our souls parallel.
When channels change I feel I'm running out of spells.
You call me insane.
I call this divine.
Love only grows when you leave it seconds out of time