how radio signals are transmitted at a particular frequency?

Question

for example in pune Radio mirchi has changed their frequency from 93.9 t0 98.3. hence what have they actually made changes

Answer 1

Commercial radio stations transmit signals using two types of schemes.....AM (Amplitude Modulation) and FM (Frequency Modulation).

In both types of schemes, the voice/music/audio is imposed upon what is known as the carrier wave. This carrier wave is generated at the radio station and has frequency within a certain portion of the range. For example FM radio stations typically have a range of 88 MegaHertz (Million Cycles Per Second) to 108 MegaHertz.

So, when your station changed from 93.9MegaHertz to 98.3MegaHertz, what they changed is the frequency of the carrier wave.

The music/voice/audio then is used to modulate (change) this frequency by a pre-determined amount. Other radio stations are assigned carrier wave frequencies in such a way that two adjacent stations will not broadcast on top of each other.

For example, since your station now broadcasts on 98.3 MegaHertz frequency, the adjacent stations will be assigned frequencies of 98.5MegaHertz (above your station's frequency) and 98.1 MegaHertz (below your station's frequency).

Hope this helps.

Answer 2

We can use radio to transmit and receive audio signals by electromagnetic waves, the process uses modulation and demodulation, the electromagnetic wave is transmitted at a much frequency. However sound (audio) waves are transverse pressure waves that move through air by creating both high and low pressure areas. An electromagnetic wave can be created at audio frequencies but its enormous wavelength makes it use rather unique. A n audio signal at 2,000 Hertz if converted 2,000 Hertz electromagnetic wave has a wavelength of 150,000 meters, about 90 miles long.

Answer 3

There is a transmitting freqency of the modulated signal which is generated by a tuning ciurcuit or an RL circuit. The L is the inductance coil. When you tune the tuning control the inductance varies giving different RL circuits fro different modulated waves which is picked up by the reciever. For transmitting you just change the modulating frequency from the old one to the new one as the numbers suggests.

Answer 4

Radio waves are the same as waves of light only with longer wavelengths so we can't see them. 93.9 is the frequency of the radio wave being emitted from a radio station. I believe the units of this are Mega Hertz or in other words 93.9 million cycles per second.

Answer 5

FM is frequency modulation so the frequency has changed from 93.9 khz (I think, maybe mhz) to 98.3. Frequency is distance between peaks of the wave. So the emitter just vibrates faster.

AM is amplitude modulation.

Answer 6

Slight correction on another persons response; we cannot see any EMR outside of the visible spectrum because our atmosphere absorbs/reflects everything but the visible. Thusly, we adapted to use the EMR that was readily available

Answer 7

They reduced capacitance and/or inductance to raise the resonant frequency of their oscillator. They may also have shortened their antenna for efficiency at the new freq.