NDB

Question 1

What is the frequency for NDB

Answer 1

190 KHZ - 1750 KHZ

“Hundred and a bit to thousand and a bit”

Question 2

What signal does a NDB transmit

Answer 2

Omnidirectional

Question 3

How to identify a NDB

Answer 3

By morse code

2 letters = locator (short range)

3 letters = NDB (long range)

Question 4

What is the morse code for a NDB usually transmitted on

Answer 4

AM (NON A2A)

Question 5

How is a NON A1A beacon identified

Answer 5

Requires a BFO (beat frequency oscillator)

Question 6

What does a ADF (automatic direction finding) require on the aircraft

Answer 6

Loop antenna
Sense antenna

Sensor
Receiver

Question 7

Is a sense antenna omnidirectional or directional

Answer 7

Omnidirectional

Question 8

Is a loop antenna directional or omnidirectional

Answer 8

Kinda directional depending on how aligned with signal = all of nothing

Question 9

What happens if you use a loop and a sense antenna

Answer 9

No ambiguity in direction

Question 10

What is the accuracy of a loop antenna

Answer 10

Has 2 null positions = ambiguity = could be 180° off

Question 11

What is a BFO

Answer 11

Beat frequency oscillator / tone

Used to identify NON A1A

Introduces a signal that mix with NDB signal to create tone = mix 2 frequencies to create a 3rd in the audible range

Question 12

What is ANT

Answer 12

When the loop antenna is disconnected = increased clarity of identification

But no bearing is available

Some indicators might park needle at 90° or 270°

Question 13

What is the danger of ADF

Answer 13

Don’t know if it works or not

But if beacon doesn’t work then NDB doesn’t work

Question 14

What is a RBI

Answer 14

Relative bearing indicator
= relative to nose of airplane

Bearing = relative bearing + heading

Question 15

What is a RMI

Answer 15

Radio magnetic indicator

= RBI + compass
= rotates like compass = QDM (head) QDR(tail)

Question 16

What happens is compass card is stuck in a RMI

Answer 16

Turns into a RBI with random heading at top (what it froze on)

Question 17

Where is variation measured for NDB

Answer 17

Aircraft

Question 18

What does BFO do

Answer 18

Creates time for NON A1A

Question 19

What is the NDB cone of confusion

Answer 19

Area above NDB where signal is disturbed

40° either side of vertical

Question 20

What is the difference between fixed and moving card ADF

Answer 20

Moving card has heading bug

Question 21

What is NDB homing

Answer 21

Needle starts to move opposite direction to drift

If you make corrective turns to keep needle at 12 o’clock

= Cheever approach to NDB

Question 22

What is accuracy if NDB

Answer 22

+/- 5°

Question 23

What happens to NDB distance at night

Answer 23

Distance signal travels increases

Usable distance decreases

Question 24

How much do u need to increase power by to double and triple the range of a NDB

Answer 24

Double = 4x power 
Triple = 9 x power

Question 25

What is static interference on a NDB

Answer 25

Most likely caused by active CB

can make ADF completely unreliable

Question 26

What is night / twilight effect on a NDB

Answer 26

Occurs between sunset / sunrise

Causes ‘hunting needles’
Due to
Sky waves + surface waves mixing which can lead to fading

Question 27

What is coastal refraction NDB

Answer 27

The signal refracting due to a change in speed over the coastline

Question 28

When is there no coastal refraction error in the NDB

Answer 28

If the NDB is on the coast exactly

If the A/c is on a angle of 90°

Question 29

How does distance inland affect coastal refraction NDB

Answer 29

Further inland = worse error

Question 30

What is multi path propagation (mountain effect) NDB

Answer 30

Radio waves bounce (reflect) off the terrain and follow several paths between the NDB and A/C

Question 31

What is bank angle error (Dip) NDB

Answer 31

Needle points into turn

Question 32

What is quadrantal error NDB

Answer 32

Aircraft structure bends incoming wave

Least error on cardinals (not 0)

Worst midway between