What is radar?

Radar is an abbreviated term for radio detection and ranging. They are instruments that detect surrounding objects by sending RF energy and receiving smudges; energy reflections from these materials. Since radar uses microwaves which are considered short wavelengths, this means that the accuracy is very high. The reflected energy indicates the direction and distance from the radar to the object.

Radars work on; a "line of sight", meaning there should be no obstacles around the radar. Having antennas such as masts and other antennas in front of the radar will result in the signal hitting these antennas and being reflected back, giving false targets and creating "shadow zones", which essentially are black spots on the radar screen.

The installation of a radar is something that must be considered carefully, and there are some points that should be considered and followed closely. if you are installing one:

1. The radar should be mounted above and out of the way of the crew. Radar beams are focused energy that can be harmful to people, although modern radars have significantly less radiation than before.
2. It shouldn't are there any obstacles for the radar on critical areas.
3. If more than one radar is present, they require vertical separation. The radars must be free from each other's vertical beam width. (At least 45 cm vertical distance)
4. The installation and mounting location must be able to support 6x the weight of the antenna.
5. The recommended installation should be 8 feet across the door. ck and no higher than 30 feet above the water, so to aim at Close range is not provided.

The microwaves that are sent from a radar travel in an almost straight line, and when this When the wave hits a frame, it is reflected back to its original position. This principle is constant through all radars, where the reflected weather is what is used to determine certain measurements. The "brains" of the radar use this information to give the user an accurate display of the target.

The object's distance from the ship is calculated from the time it takes for the reflected wave to bounce back to the radar. The longer it takes for the reflected wind to reverse, the further away the belt is. The distance is determined using the following calculation:

D = ½ * (c*T) or D = (c*T) / 2

D = Distance between radar and object
c = Speed ​​of light
T = Time between sending wave and receiving reflected wave

Since the time (T) is for a complete trip of the microwaves, it must be divided with two, to determine the distance between the radar and the object otherwise you would end up with double the distance, resulting in invalid target readings that could put you and other boats in danger.

There are twoå types of radar, "Dome" and "Open Array". Dome radars typically have a larger beam width compared to Open Arrays. Usually (although this is not always the case) dome radars are located on smaller, non-commercial vessels and pleasure boats. They weigh less, are cheaper and use less power depending on; the strength of the radar.

Open Array Radars are often found onå Military, commercial and long-distance jet ships that carry icebreakers. Usually, Open Array radars are more powerful, which makes targeting at Longer distances can be identified. The narrower beam angle also provides; better discrimination and targeting when several objects are in close proximity to each other. However, the cost and weight are a counterargument to these.

Radar is defined in 2 bands, S-band and X-band. These två bands have different frequencies, and therefore they are both beneficial, depending on scenario.

S-band has a 2-4GHz bandwidth and longer wavelengths than X-band. På due to the longer wavelength and lower frequency, they are attenuated less, which means that they can detect targets on Longer distance than X-band. Interestingly, S-band waves are not well reflected by water, making them excellent for marine navigation.

X-band works on; an 8-12GHz bandwidth, which has a much shorter wavelength than the S-band. Thanks to the shorter wave length, the waves are straighter and reflect better. The shorter the spring, the more accurate the radar antenna. While this is beneficial, it means they are limited in range compared to S-band. På because of this, they are often used together, giving the ship the best coverage for long-range targets, while providing accuracy on; close range.

Radars can have a variation in detection range depending on; the beam angle and power etc... but there is one key factor that will always determine how far a radar can detect; Installation height.

Waves from the radar can be affected by diffraction, causing them to bend somewhat along the surface of the earth. This effect allows radar to "see" beyond the human eye's line of sight. In general, the diffraction allows the radar to go about 5% further than the line of sight. Although we can only see up to the Earth's visible horizon, the radar can identify objects and targets beyond this. The calculation for this is:

D = (√A1 + √A2) * 2.2

D = Radar sight distance ;nd
A1 = Höjd på radar installation
A2 = Height of the reflective weight of the object

By increasing the height of the antenna installation, you in turn choose the radar's sight distance. To change the height of the object that reflects the wave would naturally also Check the line of sight... but you can't check the height of the a rock surface.