AV7212 TECHNICAL SEMINAR AND REPORT WRITING
KATHAN IRISH
2018603017
Who is my
God?
RADIO
Radio is a wireless device.
It transmits (or) receives data(messages) in air
medium as well in vacuum.
It uses Electromagnetic waves for carrying the
information.
Electromagnetic waves that is used in the
Radios is termed as Radio wave which has the
frequency range of 30 KHz to 300 GHz.
Electromagnetic Spectrum
What is a wave?
For instance take water waves as
example
Tidal Waves Transverse Waves
(or)
Longitudinal Waves
Water Waves
When a stone is dropped in a pond of water, a
combination of transverse waves and
longitudinal waves are produced on
the surface of water. When a
transverse wave travels horizontally in a
medium, the particles(water) of the medium
vibrate up and down in the vertical direction.
Waves produced on the surface of water is
neither transverse waves nor longitudinal
waves.
Nature of waves
Transverse Waves:
Movement of the particles are parallel to the
motion of the energy transfer(i.e., propagation of
wave). Its need medium for its propagation.
Example: Sound waves.
Longitudinal Waves:
Movement of the particles are at perpendicular to
the motion of the energy transfer. It can travel in
vacuum.
Example: Electromagnetic waves.
Examples of types of waves
Sound Waves:
In sound waves, energy is transferred through
vibration of air particles (or) particles of a solid through
which the sound travels.
Water Waves:
In water waves, energy is transferred through the
vibration of the water particles.
Electromagnetic Waves:
In electromagnetic waves, the electric field and
magnetic field are perpendicular to each other.
Here, energy is transferred through vibrations of electric
and magnetic fields.
Cause of Electric and Magnetic Fields
Electron
Magnetic Field Electric Field
Simplified Diagram
electric field
Flow of Electrons
Flow of electrons
is termed as
electricity
Is electron is really revolving around the
nucleus (or) moving straightly (or) at rest?
According to atomic theory Ernest
Rutherford and Neils Bohr strongly
believed that electron revolve
around the nucleus
Heisenberg’s Uncertainty Principle
It is impossible to determine
simultaneously with high precision
both the momentum and position of
an microscopic particle like
electron.
Wired Medium
Electron is the information
carrier in wired medium.
Wireless Medium
Electromagnetic waves is
information carrier in wireless
medium.
They travels with the velocity of
3x108 meter/second.
History Of Radios
The origin of radio
invention is the
discovery of
Electromagnetic waves.
James Clerk Maxwell (1831-1879)
Birth: 13-05-1831
Died: 05-11-1879
Maxwell showed that
the equations predict the
existence of waves of oscillating
electric and magnetic fields that
travel through empty space at a
speed that could be predicted
from simple electrical
experiments.
Maxwell obtained a velocity of
310,740,000 metres per second.
Heinrich Rudolf Hertz (1857-1894)
Birth:22-02-1857
Died:01-01-1894
Hertz proved the
existence of the
electromagnetic waves
experimentally in
1888.
Hertz Experiment
Antenna
Spark
Gap
Receiver
Transmitter
When a transmitter is powered, a spark
is produced at the receiver due to
Electromagnetic wave propagation.
Hertz's first Radio Transmitter
Spark
Gap
Spark gap is about 7.5mm.
A dipole resonator consisting
of a pair of one meter copper
wires which has zinc sphere
at its end.
The diameter of zinc sphere
is about 30cm.
Hertz's Radio Wave Receiver
Simplified Circuit Diagram of
Hertz’s Radio Model
Hertz's proof of the existence of airborne electromagnetic waves
led to an explosion of experimentation with this new form of
electromagnetic radiation, which was called "Hertzian waves"
until around 1910 when the term "Radio waves" became current.
Nathan Beverly Stubblefield (1860-1928)
Birth: 22-11-1860
Died: 28-03-1928
He demonstrated wireless technology in public in
the year 1892.
He switched to using ground currents instead of
induction.
He was able to broadcast signals as well as voice
and music In 1898, again he demonstrated wireless
to a documented distance of about 535 meters.
Later in 1902, he showcased a ship-to-shore
broadcast on the river Potomac in Washington DC;
for this, he received a patent for wireless telephone
in 1908.
Jagadish Chandra Bose (1858-1937)
Birth: 30-11-1858
Died: 23-11-1937
In 1896, he demonstrated radio
transmission to the British Governor
General at Calcutta in India.
The transmission covered a distance of
around 3 miles.
The instrument he used, the Mercury
Coherer attached to a telephone detector,
is still displayed at the Calcutta University’s
Science College.
Bose had overcome Hertz’s problem of
waves not being able to penetrate through
mountains, walls or water. Marconi’s
Coherer and Bose’s Coherer were exactly
the same.
J C Bose’s Radio Apparatus
Bose's 60 GHz microwave apparatus at the Bose Institute, Kolkata,
India. His receiver (left) used a galena crystal detector inside a horn
antenna and galvanometer to detect microwaves. Bose invented the
crystal radio detector, waveguide, horn antenna, and other
apparatus used at microwave frequencies.
Nikola Tesla (1856-1943)
Birth: 10-07-1856
Died: 07-01-1943
Tesla invented the induction coil or the
Tesla coil after he came to the US in the
year 1884.
A Tesla coil is a device required to send and
receive radio waves (it is said that Marconi
relied on this coil for his experiments).
In about 1895, unfortunately, Tesla’s
laboratory was completely destroyed by fire
when he was preparing to send a radio
signal about 50 miles to the West Point,
New York.
Father Roberto Landell de Moura (1861-1928)
Birth: 22-01-1861
Died: 30-06-1928
In June 1899, he had
successfully transmitted
audio (i.e., Voice signal)
over a distance of 7
kilometres (4.3 miles).
He was the first person
to transmit the voice in a
Radio Waves.
Guglielmo Marconi (1874-1937)
Birth: 25-04-1874
Died: 20-07-1937
Twenty years after the telephone was
invented, music was set down on
telephone line and Marconi was the one
responsible for the radio signals.
Hertz’s discovery of the radio waves that
he realized it could be employed for
receiving and sending telegraph
messages; he referred to it as wireless
telegraphs. Marconi’s earliest radio
transmissions transmitted coded signals
to only a mile far in the year 1896.
World First Radio Transmitter Station
Conrad Radio Studio:
1919 - Dr. Frank Conrad, Westinghouse engineer and scientist, conducted experimental
ham radio broadcasts on 75 watt 8XK from his garage in Wilkinsburg, PA (above in
1920) in 1919; November 2, 1920 - Station KDKA, Pittsburgh, PA (established by Conrad
at request of Westinghouse), made nation's first commercial broadcast of election results
of Harding-Cox presidential race; first commercially licensed radio station in United
States.
Marconi with his Radio Transmitter
Fight for Patents
After a lot of lawsuits, the US
Supreme Court restored Tesla
(who had died a few months
earlier) as the inventor of radio.
Commercial Radios
Worlds first commercial radio
Initially, Amplitude
Modulation(AM) was used
commercially and then Frequency
Modulation(FM) is also developed.
AM and FM Frequency Range
• AM Frequency Range: 540KHz to
1600KHz.
• FM Frequency Range: 88.1MHz to
108.1MHz.
CXA1019S
TDA7000
TEA5767
Today’s Scenario
Use of Radios in Ships and
Aviation
Use of Radios in Ships and
Aviation
Guess?
Use of Radios in Ships and
Aviation
Use of Radios in Ships and
Aviation
Use of Radios in Ships and
Aviation
Use of Radios in Ships and
Aviation
Use of Radios in Ships and
Aviation
Use of Radios in Ships and Aviation
Use of Radios in Ships and
Aviation
Use of Radios in Ships and
Aviation
SSB(Supressed Side Band) AM signal is
used in both the Aircraft as well as in
Ship.
For Telephony, the frequency used is
2182KHz. The code for this is MAYDAY
MAYDAY MAYDAY.
For Telegraphy, the frequency used is
500KHz. Here, the Morse Code is
employed.
