1. The Torch: The simplest way to see something in the dark is to shine a torch or searchlight onto it. The obvious disadvantage is that the enemy can see your torch and therefore where you are. Close enough to be uncomfortable at any rate. An alternative is to use flares of various kinds but then the enemy know they have been seen and flare light is neither clear nor long lasting.
2. Active night vision equipment: Active night vision equipment projects an electromagnetic beam like a torch onto the target and then picks up the reflection and turns it into a picture the human eye can see. This beam is normally infra-red which is just below the frequency visible to the human eye but it can be a type of laser light. It is like shining a torch on the target that no one else can see. The problem with active night vision equipment is that anyone else with a receiver for, say, infra-red can see where you are looking from as plain as if you were shining a torch. This kit used to be issued to drivers at one stage so they could see their own infra-red headlights but the practice pretty much stopped when both sides had the kit.
3. Thermal imaging equipment: All objects warmer than – 273° give off heat for complicated reasons to do with black-body-radiation and quantum. This heat can be picked up and turned into a picture by thermal imaging equipment because heat such as you feel from a fire is actually an electromagnetic wave similar to light but at a lower wavelength. This type of kit is excellent because it does not give you away and can see through light fog, rain and smoke – but at the time of writing the picture could be better.
4. Night glasses: These are pretty ordinary binoculars except the object lens – the one furthest from your eyes which collects the light – is much bigger than normal. But just like a normal pair of ‘binos’ it focuses the light it collects onto the rear lens and then onto your eyes. Because of the larger size of the object lens more light is collected than by your eye and therefore the image is brighter. Quite a lot brighter. Until the advent of electronic night vision equipment this was all we had and night glasses were widely used particularly at sea where object lenses of over 2in were used. There were also some special eye-drop drugs developed to use with night glasses which made your pupils open wider to collect more light – so count yourself lucky that technology has moved on.
5. Passive night vision equipment: This is the kit you want to use if you can get it. Essentially it is a TV camera which collects whatever light is available coming from the target. And there is always a tiny bit of light however dark it seems to the human eye. Then the mechanism turns up the brightness with an amplifier and shows the result on a screen. Through the wonders of science this can all be made so small you don’t realize how clever it is. Helmet mounted you hardly know you are wearing it. It does need a battery power source but it does not give you away and can see clear as day in the darkest night.
Human night vision
The human eye has two types of light receptors at the back of the eyeball. They are called rods and cones because that is what they look like. Small ones obviously. The cones see colours well but not in bad light and the rods see black and white best and they work fairly well in bad light. The rods taking over is why things lose their colour and look various shades of grey to us at night.
The cones are placed mostly in the centre of the receptive patch in your eyeball and the rods mostly around the edges. This means that you see things in colour that you look straight at but not so well out of the corner of your eye. This is not obvious because your brain fills in a lot of the picture from memory. What matters to you is that your best night vision is obtained by looking at a target with your peripheral vision – out of the corner of your eye. Try this at home as most people have to test it to believe it. If you have a dog you may have noticed that he or she can see really well in the dark. This is because dogs have a lot more rods than we do. Dogs, cats and many other nocturnal animals also have something called a tapetum lucidum which is a membrane at the back of the eye. This sort of reflects more of the light coming into the eye to where it can be sensed by the retina and this is why you can see cats’ eyes shining at night.
Night-vision goggles that can be mounted onto helmets. (USMC)
Another feature of the human eye is that it takes it about 40 minutes to get used to bad light. You must have experienced coming from a light place into the dark – driving into a tunnel say – and being blind for a few moments. Well for some reason – and I don’t know exactly what it is – it takes your eyes about 40 minutes to reach their best in bad light. The thing you need to remember is that a moment’s exposure to a bright light, when your night vision is working, ruins it. And then you have to start the 40 minutes all over again. While you are doing this you are vulnerable so guard your night vision. If you have to fire your weapon or take a look at a map by torch light then close one eye – the one you shoot with if you are not shooting at the same time. This protects the night vision in your aiming eye for that all-important first shot. Muzzle flash ruins your night vision instantly so you should aim to keep your spare eye closed while you are in a shooting match.
TOP TIP!
Always use passive night vision equipment
When passive sights were in an early stage of development they were not that good if it was very dark and active sights were much better in that situation so they had a use. Now that passive equipment is so good it can work efficiently no matter how dark it is. There is no obvious benefit to active equipment and a fairly serious drawback – it could get you shot.
Summary
Always carry passive night sights – one per man if you can get them. Never use active night sights as they will get you killed. Use night vision equipment to read maps etc. at night rather than a torch because this will preserve your team’s ‘night vision’. If you have to use a light, warn the other members of your team and close one eye yourself so as to maintain night vision.
RADIOS AND MOBILE PHONES
Goals: Why communications are important
One of the reasons an army is always superior in performance to an armed mob is that confrontations at every level are won by bringing superior force to bear against the enemy at a certain point. All armies are organized in the hope of achieving this if they can. This strategy is called achieving a localized superiority of firepower – and is covered in some depth later. To bring a superior force to bear requires someone to make decisions and issue orders, people prepared to obey these orders and, of course, that these instructions be received. No communications means a headless mob not an army.
What allows an army to stay organized is its communications. It is necessary for commanders to be able to tell their troops where to go and what to do. It is even better if the troops can report back what is happening so the commanders can assess the success of their plans and send reinforcements or make other adjustments as appropriate. Without effective long-range communications no large-scale strategy can be put into action. How could a commander control the movements of a division or a battle group without being able to tell his men what to do?
History: Forms of communication