Radio Theory

Question 1

In what Frequencies do VOR operate?

Answer 1

108.1 - 117.95 MHz

Question 2

On what frequency does DME operate?

Answer 2

UHF - Ultra High Frequency

Question 3

DME are often located with_____

Answer 3

VOR stations

Question 4

What does DME do?

Answer 4

It measures distance in nm from the transmitter.

It can usually also calculate ground speed and ETE

Question 5

What does ADF stand for?

Answer 5

Automatic Direction Finder

Question 6

On what frequency does ADF operate?

Answer 6

Low frequency/medium frequency band

Question 7

What is an ADF ground station know as?

Answer 7

NDB - non-directional beacon

Question 8

What does RADAR stand for?

Answer 8

Radio Detection and Range

Question 9

Types of Radar

Answer 9

Primary RADAR - radio waves reflect off the aircraft

Secondary Surveillance RADAR - requires aircraft with transponder

Question 10

How many transponder codes are there?

Answer 10

4096

Question 11

Types of Transponders

Answer 11

Mode C - older

Mode S - has data incorporated like aircraft ID permanently

Question 12

Low and Medium Frequency band

Answer 12

Long range transmission is possible

Range is dependant on power output of beacon

Signal tends to follow curvature of earth

Subject to interference like Thunderstoms

Question 13

High Frequency characteristics

Answer 13

Well suited to long range communication

Signal quality can be poor

Subject to various forms of interference

Question 14

Very High Frequency characteristics

Answer 14

Range is subject to line of sight

Range = 1.23 x sq rt of the height.

1500’ AGL is close to 50nm

Signal quality is good (that’s why we use it for voice).

Signal travels in a straight line - useful to determine direction

Question 15

UHF Characteristics

Answer 15

Similar in all aspects to VHF

Used for DME and TACAN

Question 16

Full skilled reflection of the CDI on a GPS receiver indicates ____ of track error with each dot on the indicator equal to ___ while in en route mode.

Answer 16

5nm, 1nm

Question 17

GPS is accurate to within___ Horizontally 95% of the time

Answer 17

6 metres

Question 18

What is the frequency band used for VHF navigation?

Answer 18

108.1 to 117.95 MHz

Question 19

Full skilled deflection of the CDI on a VOR receiver indicates ___ of track error with each dot on the indicator equal to ___

Answer 19

10°, 2°

Question 20

What is the formula for the expected range of a VOR?

Answer 20

VHF Range = 1.23 x (sq rt of aircraft height + sq rt antenna height)

one decimal 33 times (the square root of the height of the aircraft plus the square root of the height of the ground station antenna in feet MSL)

Question 21

What is the frequency band used for aeronautical communication?

Answer 21

118.0–136.0 MHz

Question 22

Each GPS satellite has four atomic clocks accurate to within:

Answer 22

1, billionth of a second

Question 23

What are the practical applications of low frequency waves?

Answer 23

NDB - but I don’t know why.