• The aesthetics of the new installation are cool … with blue LEDs to illuminate the array at night.
  • The system is very fast to start up and is almost instant for changes in range.

Halo – A Circle of Light

The new radar system from Simrad is unleashed under the watchful eye of PBR’s Simon Everett.

Technology marches forward at an incredible rate, bringing us clearer imagery and higher definition over a longer range or greater depths. Much like the simple echolocation used within the animal kingdom by bats and dolphins, where their brains process the reflected sound waves to give them a mental picture of what lies ahead and in sufficient detail to distinguish between prey and an obstacle, man has always been inspired by the simple but exquisite beauty of nature, and one of the things we excel at is taking what occurs in the natural world and adapting it to our needs. What started out as the fledgling radar used to warn of approaching aircraft during the war has evolved into the sophisticated systems we have today. What has facilitated this is the ability to process data. An industry insider told me that the hardware capability has always been ahead of the ability of software to process that data. For instance, many computers in general use have quad-core chips, yet in Silicon Valley they have been able to make 100-core chips for about the last 15 years – the problem is writing the algorithms capable of dealing with that amount of information delivered in a short space of time.

I well remember the launch of the broadband radar and how I was blown away by the sheer clarity and target definition of the new technology. It was a quantum leap forwards in radar capability, providing sharp returns from small or soft objects hitherto invisible to pulse radar. As we motored down the Lymington river I could remember my first insight into this revolutionary X-ray vision. Three swans were swimming across the river at a range of about 400 yards and there on the screen in front of me were three red targets perfectly rendered and exactly in relation to our heading. There was no mistaking them for moored boats or any other objects – this radar could determine individual birds at a range of nearly a quarter of a mile.

It was, and still is, incredible and a long way from the fuzzy, green oscilloscope I did my radar exam on in the 1970s. This was radar that anyone with the ability to relate their surroundings to the screen could use. Navigation marks lining the Channel stood out like a flare path on a runway. The dark art of radar interpretation had suddenly become uncloaked, ensuring that radar would suddenly be accepted by a whole new class of leisure boater. The new radar emitted very little power too, and so it was safe for the family to be in the proximity of the antenna. This alone made it more suitable than pulse radar for smaller boats. The limiting factor, if it really is one, is that broadband radar suffers from a lack of range. It is incredibly detailed but only for what is, in radar terms, short range.

In a parallel with the advance in sonar technology, the new Halo radar from Simrad addresses the restricted range of the broadband by providing remarkable detail for both short- and long-range targets. Harnessing the down scan sonar idea, which uses a crescendo of frequencies to optimise the signal for the depth, the Halo radar uses the same technique to send multiple radar frequencies to create, in effect, CHIRP radar, which is how it provides such detail out to 48 miles with the 3ft open-array antenna – out to 72 miles with the 6ft arm – and still retains the remarkable short-range detail, which is impressive for a compact antenna. It means that in just a 25ft boat with a 3ft antenna, sat mid Channel, you can cover both coasts and keep a watchful eye on approaching traffic, commercial or otherwise.

First, a bit about the technology. The Halo uses solid-state electronics with low-power consumption and ultralow radiation emissions, so it is safe from a health aspect even close to the antenna. The system is very fast to start up and is almost instant for changes in range. It only takes one revolution of the arm to recalibrate itself, so there is no discernible delay or blanking out. The screen is another breakthrough – with a linear polariser incorporated, it is bright and glare-free, even viewed through sunglasses, from about 80 degrees to the side. It is as clear as a bell whether in sunlight or shade, unless you tip head on its side, which is when the polarisation becomes apparent, as with sunglasses on, the screen blacks out, but not when viewed normally.

The target definition is adjustable for edge definition and size. It is best to keep it on low sharpening to render solid objects as solid – the target separation is so good that on high sharpening a bridge might break up into a series of separate targets as the radar reflects each individual girder and renders it a separate return; on low sharpening the bridge will show as a solid object.

To make things even more interesting, it is possible, just like modern sonars, to split the screen and show the two returns side by side, with one screen set on band A at long range and the other on band B for high-definition close range. The processing power is able to display both returns. People will be familiar with the concept because it is like having standard sonar on one screen and down scan on the other, only now it is through the air for surface contacts. This gives a useful double vision for long-range warning and close-range feeling your way through a passage.

As on a modern camera, there are five preset modes to emphasise certain features of interest. Trails mode draws a wake astern any moving target when you are not moving. Underway, even stationary objects will be given a short trail because they are moving in relation to the base, but for anchor watch duties it makes things easy. The chart overlay mode enables the watchkeeper to easily identify way markers or landmarks on the chart with the actual radar return for accurate navigation in poor visibility – for instance, even unlit Channel markers can be identified at night.

For the avid sports fishing fraternity, there is Bird mode. Remember I said that my introduction to broadband was those three swans? Well, the Halo has taken that a stage further and will display a flock of active birds in blue. For fishing, this enables the skipper to see diving birds over a shoal of fish well beyond normal eyesight and steam over to where the action is.

Of more interest to everyone afloat is the weather – more importantly, approaching fronts or deteriorating weather systems. In Weather mode, the Halo will accurately define rain showers in just the same way as the Meteorological Office radar does, with light rain in yellow getting increasingly denser through to red for heavy rain, which also often goes hand in hand with strengthening wind and poor visibility, giving you plenty of warning of impending bad weather long before you encounter it.

The aesthetics of the new installation are cool too, with blue LEDs to illuminate the array at night. For those with existing blue LED cockpit and underwater lighting it is a perfect match and will provide your craft with an existential glow.

This new development is a logical progression, but it has been a while coming. The results, though, have been worth waiting for. The drawback, if there is one, is the cost of this ability to see into the future, at around £5,000 for the 3ft version going up in £500 increments for each extra size. But then, opticians always did know how to charge … Have you had to buy a new pair of glasses recently?

More info: Simrad Yachting

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