EQT 1 Radio theory Flashcards Preview

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Flashcards in EQT 1 Radio theory Deck (21):
1

What is electricity

A form of energy produced by the movement of electrons in atoms. It can be used to transmit and receive electromagnetic energy.

2

What are radio waves

How fast do they travel?

Electromagnetic energy that are similar in behaviour to light waves.

Travels at 3000000000 metres per second

3

What is audio limited by?

Range

How loud someone speaks

Absorption by materials within range

Attenuation

4

What is one wave cycle

Each time wave travels from zero up down and back to zero this counts as one cycle

5

What is amplitude

The max displacement or value attained by the wave from its mean value during the cycle

Basically from zero to peak and back to zero

6

What is wavelength represented by?

Lambada

7

What is a wavelength

The distance in metres or part of a metre between corresponding points in consecutive waves.

8

What is the frequency

Cycle per second - hertz

9

What is 1m wavelength in MHz

300 MHz

10

How do you calculate velocity

Velocity = frequency x wavelength

11

If the wavelength is longe is the frequency higher or lower?

Lower

12

What are carrier waves produced by?

A local oscillator

13

Local oscillator can manipulate what?

Amplitude or Frequency

14

What does AM stand for

Amplitude modulation

15

What does FM stand for?

Frequency Modulation

16

What does a modulator do?

Combines the audio and carrier wave

17

What are the advantages or FM

Resilience to noise

Easy to apply modulation at low power - no boosting of amplitude required

Use of efficient RF amplifiers - less battery power required

18

Advantages of AM

Stronger stations can override weaker

A heterodyne (squeal) indicates a blockage

19

Is AM or FM used in ATC

AM

20

What is the ideal length of an antenna

The same as wavelength of the frequency transmitted

21

What does a RF amp do?

Makes signal stronger but also amplified static - has a noise gate fitted