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Getting the best from your radar

 

 

Simrad® radars are really simple to install – four bolts, one cable, power on and you're good to go. But, to get the best out of your radar there are some key things to take into account starting with the installation.

 

Craig McMillan is a Navico® product expert, he's based in Auckland, New Zealand and has a lifetime's experience in radar. He outlines the key issues.

“It’s vital that, you have a good installation. We see a range of problems from bad power supplies causing the radar at to drop out or not work, to issues with obscure targets, or scattered targets due to obstructions. We also see problems where people have pulled the cable too tight and have pulled the plug off in the process, but these are all issues that can be avoided or resolved.”

So here are his 10 top tips for getting the best from your system.

 

 

 

1: Power Supply

 

Ensure that the radar has a good power supply and is fed from a correctly rated circuit breaker. Problems with bad power supplies, which cause the radar at to drop out or not work, are quite common so it’s important to get this fundamental issue right.

2: Mounting

 

Make sure that the radar antenna is mounted so that echoes are not obscured by vessel structure, such as hard tops, masts search lights etc.

 

Calculate the beam angle to ensure that the beam passes above the bow of the vessel or front edge of the hard top where it is mounted.

 

This installation could suffer decreased performance as the radar energy is either reflected or absorbed by the hard top.

This may mean using a pedestal to lift the antenna up off the hard top.

Specific clearance dimensions are listed in the manual for each model but here is an example.

 

For every increase of 200mm (7.87”) of dimension (A), increase the height (B) by 80mm (3.15”).

 

 

3: Horizontal Alignment

Make sure that the antenna is mounted so that it is horizontal when the boat is in its normal underway attitude. For power boats that have a bow up attitude, it may be necessary to put a wedge under the rear part of the antenna, to bring the antenna level. (In this instance it may look like the radar is pointing down when at rest.) For yachts, there are gimbal brackets available which help when the yacht is heeled. Otherwise, if it is mounted on a mast, then it is important to understand that there may be a loss of targets to the sides of the yacht but generally targets in the fore and aft sectors are OK.

 

If possible, ensure that the location site provides the scanner with a clear view all round the vessel.

If installed on power boats that have a steep planing angle, it is recommended to tilt the scanner angle down at the front. (Beam angle is 11° either side of horizontal).

4: Cables

Ensure that the cable is run without damage from pulling excessively on the cable when running through the boat. The most common way of causing damage is to tie the mouse line in the wrong place where it will put pressure on the connector.
Instead, connect the mouse line to the outer jacket of the cable so that the strain of pulling is transferred to the stronger outer jacket of the cable. Use some small cable ties to secure the mouse line to the outer jacket as well if there is sufficient clearance.

A: Mouse Line
B: Electrical Tape
C: Cable Tie

5: Installation Setup

The correct installation setup is vital. One of the primary uses for the radar is to pick out buoys and vessels and show what bearings they are to you, so it’s vitally important that the bearing alignment is set up correctly. If the antenna is not pointing directly straight ahead at the bow of your boat, the angles of everything it sees will not be correct. The antenna height setting is critical as it is used in the sea clutter suppression calculations. An antenna mounted too high up will get increased sea clutter close to the vessel, which can obscure smaller targets.

The antenna height setting is used in the signal processing to set the correct sea clutter curve and supress sea clutter returns close to the boat. This makes it easier to see the smaller targets that we are interested in.

6: On Board Sensors

Make sure that on board sensors such as the GPS and compass are correctly installed, connected and calibrated. These devices input key information and if this data is not accurate, other valuable functions such as chart overlays and VelocityTrack™ will be affected. Remember, ‘garbage in/garbage out’, as the saying goes.

 

7: Understand the Controls

Understand what the main controls of the radar do. This may sound obvious, but it’s easy to get overwhelmed with the number of functions and possibilities that are on offer. The reality is that there are four key controls and understanding what they do will help to ensure that you can have confidence in the information you are receiving.

The four controls are:

A) Gain – Like volume control on a radio, turn it up to see the targets, but not so high that the targets get obscured by clutter. Auto gives a very good setting.

B) Rain control – Used only when in rain or snow to reduce the clutter on the screen and see targets behind the clutter. Use sparingly. This should be set to zero in fine conditions.

C) Sea Clutter control – This can be set manually, or you can use the preset modes: calm, moderate or rough. Take care if you are setting manually as it could blank out small targets close to the boat. Auto Sea Clutter is often the simplest and best option. Auto Sea Clutter will automatically adjust the sea clutter dynamically to provide increased suppression when looking into the waves and reduced suppression when looking down the waves.

Downwind signals deflect away = less clutter

Upwind signals reflect back = more clutter

stronger-targets-downwind-v2.png

Stronger Targets Downwind

D) Mode – Simrad® radars have modes for; Harbour, Offshore, Bird or Weather (depending on model). Make sure you are in the correct mode for the task. For example, Harbour mode will set the radar into 60 RPM, (depending on model), when you are operating at close quarters. At 1 sweep per second this gives a much faster update which is better for showing fast moving targets in real time.

8: VelocityTrack

Use Velocity Track. This is a really helpful tool that colours targets differently depending on the potential risk that they pose ie. If they are approaching or diverging. Targets that present a conflict will appear in a different colour to draw your attention. For example, if a ferry is leaving a cluttered wharf it might be difficult to pick it out initially. If it is coming towards you and presents a risk it will pop up on your screen in yellow. When it has passed and is moving away it will be blue.

Approaching target

 

 

Stationary targets, or target under threshold velocity.

 

 

Diverging target.

9: Blanking Sectors

Use blanking sectors to stop transmission in areas where there may be bad reflections, or in areas where people may be positioned. For example, if there is a mast behind the radar antenna this could cause false echoes as the signal bounces off the mast which could cause the radar to show targets where there aren’t any.

10: Advanced features

 

A) Dual Range™. This is like having two radars in one as it allows you to have one range set to see targets that are close to your boat, while viewing a longer range for vessels approaching further out. Our Halo radars use a patented technique of processing the shorter range signals alongside those of the long range responses. In many cases with other manufacturer’s equipment this is achieved by alternating the transmissions which can slow down the update rate by 50%. Our system means that the image is updated just as quickly in dual range as it is in single range. This dual range option and the fact that it doesn’t compromise the image, delivers big benefits when it comes to better situational awareness.

B. Chart Radar Overlay. Overlaying the radar image onto the chart makes life much easier when it comes to identifying key features, especially channel markers. Targets that are not shown on the chart are most likely boats or obstacles to be avoided. VelocityTrack also works on chart radar overlay to show where potential conflicts might be.

C) MARPA (Mini Automatic Radar Plotting Aid). An advanced and sophisticated tool that is invaluable when it comes to collision avoidance. Simply tap on a target and select acquire. This will provide useful collision avoidance information such as the other vessel’s course and speed, closest point of approach (CPA) and time to closest point of approach (TCPA). Once you’ve used it for the first time in anger you’ll never want to be without it again.

 

Craig McMillan

PRODUCT EXPERT

After a career in avionics in the New Zealand Airforce Craig was a distributor for Simrad® and B&G® products for 20 years before joining Navico as Product Expert, a role that he has held for the last six years.