Pulse Length
Short/Medium/Long depending on range scale in use.
Short pulse- better definition
Long pulse-better range
Carrier Frequency
Radio frequency on which the transmission is made.
(X or S band)
X band
+ state preferred adv.
3cm about 10 GHz
Better Resolution, preferred for navigation.
What is attenuation?
Which band frequency suffers most?
the loss or reduction
of signal strength
over distance or
through a medium (rain)
X band suffers from attentuation more than S band.
S Band
+ state preferred adv.
10 cm about 3 GHz
Better in rain, longer range.
Sea Clutter (or STC; Sensitivity Time Constant)
+Correct setting?
It reduces the sensitivity of the receiver from the centre out.
Proper Setting: Clutter reduced, echoes distinguishable.
Precipitation Clutter
Suppresses reflected echoes from rain, hail or snow to clear the display.
Via video processing it doesn’t display leading edge returns.
Detection Characteristics of Radar Targets
MASTS
Material
Aspect
Size
Texture
Shape
RADAR meaning
RAdio Detection And Ranging
Setting up a Radar
(3 points)
Brilliance
Range
Gain - light background speckle (70%)
Tuning - need to be receiving something even if it is own wake. REFER TO MANUAL.
Clutter- Sea and Rain
Pre departure radar checks
(+ every 4 hrs WATCH min)
(list 6 steps)
then done < 4 hrs of radar watch.
(MGN 379)
Good Radar Practice
(5 points)
CHAPS
1. Clutter controls
2. Heading Marker
3. Awareness
4. Performance
5. Shadow/Blind Sectors
Performance Monitor
Verifies the radars ability to detect targets and provide accurate information.
Will also identify issues or faults within the radar system.
Read the manual for your particular radar.
Ensure radar range rings are on.
Radar Displays
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)
Ground stabilisation
(6)
Sea Stabilisation
(6)
Errors of Radar
(8)
How do you make sure your heading marker is aligned?
How do you set you radar up for a SART?
On the X band radar as most vessels have one:
big randy girls take cock
(BIG) Brilliance: N/A
(RANDY) Radar range scale set to 6/ 12 miles.
(GIRLS) Gain: Normal
(TAKE) Detune the radar: this reduces the clutter without reducing the SART echo.
(COCK) Clutter controls:
-Sea clutter set to min.
-Rain Clutter to match conditions/doesn’t matter
What could be fitted to a navigational mark to make it more radar conspicuous?
A racon or radar reflector.
When should you not adjust your heading marker?
-when alongside a berth
-using bearings of targets which are close to the vessel, not distinct or have not been verified visually.