Comm 03: Basic radio systems

Question 1

Components of a basic radio comms system

Answer 1

Transmitter, TX antenna

Receiver, RX antenna

Question 2

Transmitter

Answer 2

RF section
Oscillator/Generator: Generates EM energy at the desired frequency. This frequency is called the CARRIER wave
Amplifiers: increased the power of the signal to a level sufficient for transmission

Modulator section
Used to enter the desired info into the transmitter (microphone, keyboard, computer, etc)
Impresses the intelligence onto the carrier wave using many different methods

Question 3

Carrier Wave

Answer 3

The RF section generates a carrier wave
This carrier wave is a constant frequency and contains no intelligence
The carrier wave is the frequency that you select on the radio: 126.7, 121.5, etc

Question 4

Receiver characteristics

Answer 4

Frequency coverage
Sensitivity
Selectivity
Fiedelity

Question 5

Antenna information
Antenna gain
Polarization
Receiving

Answer 5

Antennas couple the radio system to free space
A single antenna can both transmit and receive RF signals, but not at the same time

Transmitting antenna

Antenna Gain
The measurement of an antenna’s ability to radiate energy in a particular direction
Gain is a function of antenna size and shape

Antenna polarization
Orientation of transmitting antennae determines polarization of the radio wave
Receiving antennae must have a similar polarization as the wave they are receiving in order to intercept it efficiently
Receiving antenna

The EM waves from the transmitting antenna excite the electrons in the receiving antenna
This causes an electric current to be formed and conducted to the receiver