RADAR

Question 1

Pulse Length

Answer 1

Determined by the design of the modulator circuit.

Short/Medium/Long depending on range scale in use.

Question 2

Carrier Frequency

Answer 2

Transmission radio frequency

Question 3

X band

Answer 3

3cm 9-10 GHz

Better Resolution, preferred for navigation

Question 4

S Band

Answer 4

10 cm 3 GHz

Better in rain, longer range

Question 5

Sea Clutter (or STC; Sensitivity Time Constant)

Answer 5

Reduces reflections from waves near ship by reducing sensitivity of receiver from centre out.

Proper Setting: Clutter reduced, echoes distinguishable.

Question 6

Precipitation Clutter

Answer 6

Reduces reflected echoes from rain, hail or snow to clear display.
Via video processing it doesn’t display leading edge returns.

Question 7

Detection Characteristics of Radar Targets

Answer 7

MASTS

Material
Aspect
Size
Texture
Shape

Question 8

RADAR meaning

Answer 8

RAdio Detection And Ranging

Question 9

Setting up a Radar

Answer 9

1. Check scanner is clear
2. Turn ON
3. BIG RANDY GIRLS TAKE COCK

Brilliance

Range

Gain - light background speckle (70%)

Tuning - need to be receiving something

Clutter

Question 10

Pre departure radar checks

Answer 10

then done < 4 hrs of radar watch.

(MGN 379)

On + Running

Performance Monitor

VRM against range rings

EBL using charted object with heading marker against compass

Question 11

Good Radar Practice

Answer 11

-Quality of radar performance checked regularly
-Misalignment of heading marker can lead to misinterpreting collision situations.
-Small vessels, ice and other floating objects may not be detected by radar
-Video processing techniques used with care
-Echoes may be obscured by sea or rain clutter
-Masts or other structural features may cause shadow or blind sectors on display.

Question 12

Performance Monitor

Answer 12

Provides a check of the performance of transmitter.

Plume length - Strength of echo received

Question 13

Radar Displays

Answer 13

H-Up : Un-stabilised- does not utilise heading input. Reverted to after heading input failure.
C-Up : Stabilised - heading input from a Gyro or transmitting heading device (THD)
N-Up : Stabilised - heading input from a Gyro or transmitting heading device (THD)

Question 14

Ground stabilisation

Answer 14

• Coastal Navigation
• COG + SOG input
• Speed and Heading from GNSS
• Set and Drift visually shown
• difficulty determining true aspect
• fixed target will appear stationary

Question 15

Sea Stabilisation

Answer 15

• Collision Avoidance
• CTW + STW input
• Speed and heading from Gyro and Log
• Doesn’t account for set and drift
• true aspect easily determined
• fixed target will have a vector direction rec. to set and speed indicates rate of drift

Question 16

Errors of Radar

Answer 16

Side Lobe effects
Spurious Echoes and Effects
Radar Interference
Indirect echoes
Multiple Echoes
Shadow Sectors
Blind Sectors
Radar Horizon