Reflections of radar signals are not simple to figure out. A major area of study is devoted to it, and the field of stealth technology has emerged as a result.
The radio signal is then sent from the transmitter and expanded as a beam. When it hits an object, several things occur. Some of the beam is absorbed, while some is transmitted. Some of the pulse is reflected back to the transmitter.
The reflection of an object can be dispersed over a wide angle depending on the form of the object. This is the case for objects that are round in shape. Flat objects will reflect better, but not necessarily back towards the antenna.
Rotating the antenna allows for a wider and more effective scanning of a larger and better area, improving received signals.
The reflected signal is considerably less powerful than the original radar radio pulse that was sent. The stronger the original signal, the greater the echo return. The better the received signal, assuming that the receiver is more sensitive.
In general, radars will “see” objects constructed of conductive materials that reflect RF energy back to the source.
Not all materials respond equally well to radar. Metals, for example, are superior to insulators like wood or fiberglass because of the electrical conductivity. Carbon fiber is superior than Kevlar or fiberglass. Surfaces that are flat rather than curved reflect more effectively.
No materials are truly invisible to radar, there is just a spectrum of reflectively that needs to be considered.
Can radar detect small wooden boats?
Yes, even the tiniest of boat made of wood may be detected by radars, although it is not without its difficulties. The major problem is the clutter and multipath caused by the numerous bounces off the water’s surface.
If a small boat is moving, doppler processing can improve visibility, but it also needs good phase noise and high velocity. Antenna design, band selection, waveform choice, and processing technique can all have an impact.
Resonances of the ship might be detected by a broadband radar, potentially significantly improving visibility.
Even excellent radar signals can be lost in heavy rain or become intermittent. The formation of waves is a problem. Ground clutter is formed by the angle and size that a wave presents to a radar aerial.
Modern frequency agile radars can handle ground obstruction and weather better, but they are still very uncommon.
Taking all this into consideration it’s highly recommended to get a radar reflector for you boat to ensure detection.
What is a Radar Reflector?
A radar reflector is a device that’s attached to a boat in order for it to be more visible on radar. Radar reflectors are made up of several pieces of metal that overlap and form a geometric figure that greatly reflects radars.
There are a variety of styles and designs to choose from, and several boating safety organizations have evaluated a number of radar reflectors to determine which ones seem to work best, obtaining varied results that show that even with a radar reflector, a boat can be difficult to detect on radar.
A radar reflector allows for a much more safe sea travel by reflecting radar signals, resulting in a return that can be seen clearly on radar screens. Larger ships will be able to see tiny boats in front of them more easily, lowering the chance of collision. A radar reflector also makes a lifeboat easier to spot on radar scanning, allowing it to be found much more quickly.
Can Radar Detect a Wooden Aircraft?
Yes, a wooden airplane will be seen with radar. It would not be completely invisible to radar, but it would show a considerably lower radar signature.
Trees are one of the most prevalent reflection points, but since they don’t move, the Moving Target Indicator (MTI) circuit can filter them out. Both long and short-range radars should be able to identify a plane made entirely of wood as a moving target if you could construct and fly one.
The choice of low moisture wood would be best as water reflects RF pretty easily. Still this is only making the signal weaker and possibly providing an intermittent return depending upon the planes cross-section.
Also, the problem of the engine would need to be overcome. Just like a radar reflector on a boat, any presence of metal would significantly boost the potential radar reflectively. Even a sky diver could show up on a radar with a comparably tiny amount of metal.
If avoiding radar detection in the sky is your main goal then a hot air balloon would be your best bet. Not only is the material not that reflective, the spherical shape will generally have a small radar cross section. The slow moving speed tends to get filtered out as well if not specifically looking for it. This is why most hot air balloons are fitted with transponders to enhance the visibility on a radar screen.