Radar And Arpa

Question 1

What are the time stipulation for ARPA Providing target information

Answer 1

With in 1 min it must display RELATIVE MOTION TREND, RANGE and BEARING

With in 3 min it must display, RELATIVE COURSE, RELATIVE SPEED, CPA, TCPA, TRUE COURSE, TRUE SPEED

Question 2

How to setup radar

Answer 2

Check scanner
Turn on
Wait to warm
While waiting night/day, set radar orientation(n up, relative trails,)
Turn to transmit

Big - Brilliance
Randy - Range
Girls - Gain
Take - Tune(If manual tune then adjust until target at edge of screen has best image, if in the middle of the ocean check tuning bar and tuning indicator or check that radar is in auto tune. Manual tune can be done to sea clutter or to own vessels wake.)
Cock - Clutter

Question 3

How to test health of scanner/radar performance

Answer 3

Performance Monior
To be checked before every use of Radar and once every watch
Steps in Furuno:
Menu
Echo
PM
ON
Auto change to 24nm range
Two Ring echos will appear, may need to adjust gain to display better
Measure range of Ring and compare to previous measurements and specs in operators manual inner most arc 13.5 to 18.5
Reduction in distance indicates performance reduction

Question 4

What are the potential radar errors

Answer 4

• Side lobes
• Multiple echoes, multipathing
• Spurious interference (corrected with interference rejection function)
• Shadow / Blind sectors
• Indirect echoes
• Second trace echoes (ducting and super refraction stuck between 2 layers of warm air)
• Ghost echoes from power cables
• Sub refraction

Question 5

What factors effect target detection

Answer 5

Material 
Aspect/shape
Size of target
Texture of surface
Height of scanner

Question 6

What actions to take if you loose log

Answer 6

Manual input of water speed from engine speed, or input GPS speed for ground stabilised

Question 7

How to check radar heading alignment is correct

Answer 7

Point vessel directly at a radar conspicuous target and check if it lines up with radar heading marker. If not then to correct in older radar you would have to actually readjust the heading indicator sensor on the scanner unit. In newer models they have a heading indicator offset adjustment.

Done regularly anytime a vessel crosses your bow

Question 8

Good radar practice, things to keep in mind when using Radar.

Answer 8

• PM checks regularly
• Incorrect heading alignment can give rise to misleading interpretations of collision situations
• Small vessel and ice and other floating objects may not be detected
• Video processing techniques used with caution
• Echoes may be obscured by sea or rain clutter, careful use of controls will assist
• Always use minimum clutter controls and reduce when not needed
• Shadows and blind sectors caused by mast and other structures.

Question 9

Difference between X-band and S-band

Answer 9

X-band: 3cm/9ghz, Collision avoidance at closer ranges, navigation, GMDSS pickup SART, Better bearing and range discrimination

S-Band: 10cm/3ghz, Long range scanning, Detection in rain and bad weather, less sea clutter, Collision avoidance at long range.

Question 10

Pre- Departure checks of RADAR

Answer 10

PM before sailing and at least every 4 hours while sailing
VRM against range rings
EBL agains compass bearing of a radar conspicuous object
Heading marker
Check gyro reading and radar are in alignment