What is a RADIO ?

Some months ago, we Nagpurian's got a taste of what kind of entertainment one can get when the guys at M.S.E.D.C.L. (the people managing the electricity supply in Maharashtra) go crazy and do the load shedding thing leaving you hapless without your idiot box or computers to rely on (of course, people with inverters got away for a while!). The new source of such uninterrupted entertainment was the simple radio which though was existing from a long time but was not quite making waves (at least not among the non-fisherman, people loving old songs and highly curious elders...). The thing is, the state sponsored government channel were simply way too much boring for majority of the masses and were neglected a lot. But after the entry of private entities like Mirchi, My FM, Radiocity etc (in no particular order, of course) the scene in Nagpur has changed dramatically with a major shift towards the erstwhile instrument of information. Most of my friends are now listening to lots of songs and those with radio enabled mobiles go on with a murky smirk on their faces !! Though many of us know how the thing works, except for those people who have done a minor/major course in electronics most of us don't know the intricate details of technology involved in the same. Thats why this effort. Explained in as simple terms as one can. Read on. So that you wont be dumbfounded if your grandchildren were to ask you this very question after some years when you are an oldie. Hehe...

What is it and how does it work?

Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travel by means of oscillating electromagnetic fields that pass through the air and the vacuum of space. It does not require a medium of transport. Information is carried by systematically changing some property of the radiated waves, such as their amplitude or their frequency. When radio waves pass an electrical conductor, the oscillating fields induce an alternating current in the conductor. This can be detected and transformed into sound or other signals that carry information.

Although Nikola Tesla first demonstrated the feasibility of wireless communications in 1893, Guglielmo Marconi, an Italian inventor, was the first to develop workable radio communication. He sent and received his first radio signal in Italy in 1895.

The word 'radio' is used to describe this phenomenon, and radio transmissions are classed as radio frequency emissions.

What is the difference between AM radio and FM radio?

AM stands for “amplitude modulation” – a type of signal. With AM, the amplitude of the combined audio frequency and radio frequency waves varies to match the audio signal. AM radio can develop problems with interference. This makes it hard to hear the radio show. Interference can be caused by many sources. For example, sparks discharge when a car is started, in electric motors in all sorts of electrical appliances, and even lightning. All of these things can produce interference to AM radio. As you can see, there is a lot of background noise that changes the amplitude of the radio wave signal. This creates the random crackling noises call static.

FM stands for “frequency modulation”- a type of radio transmission, the frequency of the combined waves change to reproduce the audio signal. For example, higher frequency is associated with the peak amplitude in the audio wave. FM waves do not have a problem with interference because the noise background does not modify the radio wave frequency. In addition FM waves give better sound reproduction.

Please do post any other insights that will be be valuable to the understanding of this so-commonly-used-yet-so-much-neglected-technology by clicking here.