Chapter 5: ADF

Question 1

what is ADF?

Answer 1

automatic direction finding

Question 2

what frequency band does ADF uses?

Answer 2

190 - 1750 kHz

Question 3

loop current formula

Answer 3

H sin theta

H - magnetic field

Question 4

why is sense antenna needed?

Answer 4

remove loop 180deg ambiguity (2 sides will be null in 360 range)

Question 5

errors in direction finding

Answer 5

1) vertical or antenna effect
2) quadrantal error
3) night effect
4) static interference
5) coastal refraction

Question 6

what components is in the ADF system?

Answer 6

1) ADF receiver
2) loop & sense antenna
3) radio magnetic indicator
4) control panel

Question 7

what is a loop swing?

Answer 7

determining sign and size of error in ADF installation

Question 8

when should swing not be carried out

Answer 8

+- 2 hours of sunset/rise

Question 9

Correction (D) formula

Answer 9

D = MB - (MH + RB)

Question 10

at which position will coastal refraction most affect its ADF?

Answer 10

30deg from beacon

Question 11

what is a loop & sense aerial polar diagram

Answer 11

loop: figure of 8 (2 circles)

sense: omni directional (1 circle)