Radio waves/ Gelombang Radio SMAKBO 57 2013

Radio Waves

Group 1:-Galang Adi S

-M. Suhud Farabi-Nur Azizah- Rica Aditya

Preface

ELECTROMAGNETIC WAVE

DefinitionElectromagnetic waves is waves that

can vine even there’s no medium or mediation.

Properties of Electromagnetic Waves

Electromagnetic waves can vine in vacuum area/without any medium

A transverse wave

Didn’t have any electric charge so move straight in magnetic field and electric field

Can undergo reflection, refraction, fusion, deflection, polarization

The change of electric and magnetic field happen in the same time, so the electric and magnetic field will be on the same phase and proportional

RADIO WAVE

Because the length of the waves ranged between 1 – 1000 meters and the

frequency ranged between 104 until 107 hertz.

Why it called as Radio Waves?

So….

Radio waves is a waves that have frequency ranged between 104 until 107 hertz and the

length of the waves ranged between 1 – 1000 meters. This waves function is as “courier” in

information technology. “Courier” means a waves properties that can be reflected with

earth ionosfer , so it can reach some places with a long distance on earth and can be captured by

the radio, television, handphone and etc.

Radio waves created from electric charge that accelerated through the conductor wires. This

charges generated by the electronic circuit called an oscillator.

How it

happens?

Founder…

David E. Hughes1878

James Clerk Maxwell1873

Founder…

Heinrich Rudolf Hertz1886/1888

Edwin Howard Amstrong1890-1954

Radio waves that can be captured can be a sound,

which is:

AM (Amplitude Modulation)Amplitude modulation waves as an information carrier have a big frequency , ranged between 550

kHz until 1.600 kHz

FM (Frequency Modulation)Use frequency wave modulation as an information carrier. The

frequency ranged is about 88 kHz until 108 kHz. But, from those waves, the waves that AM showed is tend to be noisy that FM, because the existance of electrical events in the air that can disturb the amplitude. In far-reaching FM is worse because can’t be

reflected through the ionosphere layer.

Radio waves that can be captured can be a sound,

which is:

FREQUENCY LENGTH Specific Wavelength Applications

Low (LF)30 kHz – 300 kHz

Long Wave1500 m

Long wave radio and long distance communication

Medium (MF)300 kHz – 3 mHz

Medium Wave300 m

Local medium wave and long distance radio

High (HF)3 mHz – 30 mHz

Short Wave30 m

Short wave radio and communication, amateur radio and CB

Very High (VHF)30 mHz – 300 mHz

Very Short Wave3m

FM Radio, police, and emergency service

Ultrahigh (UHF)300 mHz – 3 GHz

Ultra Short Wave30 cm

TV (line 4, 5)

Super High (SHF)> 3 GHz

Microwave3 cm

Radar, satellite communication, telephone, and TV channel

1. VHF and UHFThis kind of wave can’t be reflected by atmosphere layer because its scope is narrow.2.AM and FMEmission of AM wave used in broadcasting with long wave and can be reflected by the ionosphere layer

Kind of Radio Wave

Emission of FM wave used in broadcasting with VHF wave. It’s excellence is free from

electric interferention, so the music sounds melodious.

NOTE!

3.Medium WaveRadio wave with 1 MHz (1.000.000 Hz) is easy to reflected by the ionosphere layer

4.Micro WaveRadio wave with highest frequency is up to 3 GHz. If food adsorb the radiation of the micro wave, the food will be hot in short time.Microwave also used in RADAR. RADAR means search and determined trace something with microwave

The Formula

s = distance of objects that captured radar

c = 3 x 108 m/sλ = Wavelength

λ= c/f

Problems Example

Sebuah pemancar radio bekerja pada frekuensi 5 MHz. Berapakah panjang gelombang radio yang terpancar dari pemancar radio tersebut?Penyelesaian :Diketahui: f = 5 MHz = 5.106 HzDitanya: λ = …?Jawab:Λ = c/f = 3.108/3.106 = 60m

Problems Example

Gelombang radio AM memiliki daya jangkau yang jauh tanpa memerlukan relay, karena....

Jawab: Dipantulkan oleh lapisan ionosfer

Problems Example

Radio Radio wave has the longest wave length in electromagnetic spectrum. This wave can be longer than soccer field or as short as a ball. Radio wave do than just bring music to our radio. They carry signal for television and handphone too.

The Useful of

Radio Wave

TELEVISION

The antenna on the television organize receiving signals, in the form of electromagnetic waves, emitted from the television station. It is displayed on the television screen. cable companies have an antenna or dish that receives the wave broadcast from your local TV station. This signal is then sent through a cable to the House

Hand phoneAn cellular phones also use radio waves to transmit information. This wave is much smaller that the TV and FM radio waves.

How does Radio works?

Any Question?

Conclusion

Radio waves are electromagnetic radiation that occur when electrically charged objects raised frequency. Radio waves are distinguished on the basis of the frequency and wavelength range. Radio waves have 2 modulation which is beneficial for our daily lives, namely wave AM (Amplitude Modulation) and FM (Frequency Modulation).

Radio waves formula:

λ= c/f

Thankyou

Bibliography

• http://derianramdhani.blogspot.com/• http://id.wikipedia.org/wiki/Radio#Gel

ombang_radio• http://napitzfriston.blogspot.com/201

1/04/gelombang-elektromagnetik.html

• http://farahaulia04.blogspot.com/2012/03/bagaimana-cara-kerja-radio.html