RADAR more

RADAR set up:

general set-up:

check that the scanner is clear,

Brilliance, gain, anti-clutter to a min.

switch to standby.

ensure it is receiving the correct speed and heading inputs.

make one sea and another ground stabilised.
 sea stabilised and ground: sea better for aspect collision avoidance and ocean.

after warm up hit transmit. warm up time? 4 mins to warm up 5 seconds to on from stnadby.


select range scale and pulse length

display/orientation: NU, CU, HU

Mode: RM, TM

GS ss




BGTRS

Gain slight speckling
tuning: best picture

check range rings: correct number, good focus, circular, and equidistant using vrm.

and check that the heading marker aligns with the bearing scale.

check ebl with heading marker.

and check that the heading marker aligns with the fore and aft line of the ship: MGN 379

why ss i nthe ocean:

RM(T) With true trails you will see, with ss ships will be through the water, in the ocean very little set and drift so thats fine, GS: over the ground, with a lot of set and drift use GS, so coastal areas.
SS: aspect and CA.

so at ocean SS for the arpa:

Settings for ocean voyage:  and why?

NU: true bearings, gyro stabilised
own ship is fixed at the centre or offset and the course is a gyrocourse.

as the ship changes course the heading marker rotates across the screen rather than the RADAR echoes. 000G is at the top.

RM: the sum of the other ship's true motion and your true motion, most common.

relative motion, true trails allows the relative vector to be seen therefore giving the best vector for CA and the true motion of the targets trail enables it to see that ship's motion.

PL: it is normallyadjusted according to the range, The pulse width must be long enough to ensure that the radar emits sufficient energy so that the reflected pulse is detectable by its receiver. The amount of energy that can be delivered to a distant target is the product of two things; the peak output power of the transmitter, and the duration of the transmission. Therefore, pulse width constrains the maximum detection range of a target. long pl deep sea.

short pulse is good distinguishing between two ships.

http://solasv.mcga.gov.uk/m_notice/mgn/mgn379.pdf]

sea stab at coast: n coastal, estuarial and river waters where a significant set and drift may be experienced, a sea stabilised display will produce significant target trails from all fixed (stationary) objects possibly producing an unacceptably high level of clutter and masking. In such circumstances a ground stabilised display may reduce its effect and enable the observer to det


Gain is used to increase the receiving sensitivity of the radar. It need to be adjusted to a level where targets are visible but there is no other interference on the screen.

https://www.myseatime.com/blog/detail/speed-over-water-or-speed-over-ground-which-one-to-use

http://www.marcomm.ru/UserFiles/Files/Doc/ARPA%20manual.pdf  209 arpa search


sea stabilisation:
https://docs.google.com/document/d/1NT7y-hdpMygorfRiqse9TxJgm6_6YujmFMhtQgNuMQo/edit

How does sea stabilisation work? Why does it give you a better aspect?


So a sea stabilised display, gives better aspect as the ship involved is not affected by set and drift, when the tide and current is strong

by usign the speed throug hthe water

Your vessel is moving on a true course of 000 Deg. You have another vessel right ahead on a course of 180 Deg. There is strong easterly current and because of that your vessel is making good a course of 040 Deg. Other Vessel is making good a course of 140 Deg.

If there is risk of collision, what action you will take and under which rule ?

For example, as per ROR, Head on situation is when you see a ship right ahead or nearly right ahead. That is when you can see both her Mast headlights in line or nearly in line and both of her sidelights.

so you must ignore the set and drift and the sit, and aspect for CA relates to the ships STW, not GS. or GT
showing the COG may well give a false aspect of the situation.

why does it give a better aspect because the picture on the radar represents  the heading of both ship's and the vector is not affected by the tide so it shows the heading as if you looked out the windo and Ca is how the ship's aspect.
When we use speed over water the same situation would look as a head on situation. That is because when we use speed over water, it does not consider the effect of current on the vessel.

https://msi.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/RNM/310ch2.pdf

https://www.manualslib.com/manual/55737/Furuno-Fr-2125v.html?page=96#manual 

this
https://msi.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/RNM/310ch5.pdf


Without a heading input, you won't get "head up" and the target echoes appear as concentric smears, range only.

If you think about how the radar calculates CPA/TCPA, this is purely motion of the target relative to the radar and doesn't rely on anything other than a series of range and bearing observations. In practice ARPA often fudges it using other inputs, so you have to be careful.