TECHNOLOGY USED IN AMATEUR RADIO

SUBJECT:- ELECTRONIC COMMUNICATIONSPRESENTED BY:- BHARGAV KAKADIYA

Amateur radio Amateur radio (also called ham radio)

describes the use of radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radio sport, contesting, and emergency communication. 

Frequency requirements1)short wave/High frequencies(HF)

1.820-30.000 MHz2)VHF(Very high Frequencies) 144-146 MHZ

What is the difference between ham radio and ordinary radio?

Amateur radio operators are often called “ham radio operators” or simply “hams”.

Hams are not allowed to do anything with their radios that earn them money in any way.

Ham radio is two-way communication whereas ordinary radio is used to communicate in one-way. Ham radio operators can’t broadcast to public.

Modes of communication in ham radio

Morse code is the original digital data mode. Radio telegraphy which is the direct on/off keying of a continuous wave carrier by Morse code symbols, often called amplitude-shift keying(ASK), may be considered to be an amplitude modulated mode of communications. 

Analog voice- Amplitude modulation (AM), Double Sideband Suppressed Carrier (DSB-SC), Independent Sideband (ISB), Single Sideband (SSB), Amplitude Modulation Equivalent (AME), Frequency modulation (FM), Phase modulation (PM)

Image modes consist of sending either video or still images-Amateur television, also known as Fast Scan television (ATV), Slow-scan television (SSTV), Facsimile

Text and data Most amateur digital modes are transmitted by inserting audio into the microphone input of a radio and using an analog scheme, such as amplitude modulation (AM), frequency modulation (FM), or single-sideband modulation (SSB).Amateur teleprinting over radio (AMTOR), D-STAR (Digital Data) a high speed (128 kbit/s), data-only mode.

Modes of communication in ham radio

Instruments used in ham radio

HF transceiver VHF transceiver Half wave dipole antenna

mount on the top of the roof for maximum signal to noise ratio

The transmission is done through ionosphere-this layer of charged particles envelops the earth

SSB transmitter

Super Heterodyne receiver

AMATEUR RADIO REPEATER

An amateur radio repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. Many repeaters are located on hilltops or on tall buildings as the higher location increases their coverage area, sometimes referred to as the radio horizon.

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