NIGHT VISION EQUIPMENT
The Truth, the Whole Truth, and Nothing but the Truth ...
Well, hello again, fellow mouseketeers. Not too much new on this end. As always, I wait until the very (very!) last minute to crank out these articles, causing hate and discontent amongst the editors, beloved typesetters and management of this exalted publication. These articles are written between phone calls, travel, trips to the head, and everything else that seems to take higher priority. Once completed, run through the spell checker and printed out, the final copy is rushed on a gurney from the computer printer to the FAX, where it usually arrives at something like 4AM at the Police & Security News offices. Equipment has been installed to allow transmitting articles directly from our computer over phone lines to the editors, which should help. How long will it be before the entire thing is transmitted electronically, from my terminal to the editors and directly to your terminal?
This month we're picking back up on night vision. Please note a correction from the article in the last issue. Cathode sensitivity for commercial grade tubes should have been printed as LESS THAN (not greater than) 239 MICROAMPS (not milliamps) per lumen, and White Light Gain as LESS THAN (not greater than) 30,000 times. Also, I had included a typical intensifier tube data sheet from ITT, a manufacturer of quality tubes, as well as a pictorial drawing of a typical night vision system showing how everything actually hooks together. Due to tight schedules and not having someone to redraw the rough copy into a quality suitable for reproduction, the data sheet and pictorials will not appear here. Please send an SASE to my office with a note if you would like a copy for your files. The configuration, especially, will help you understand what you need if you will be purchasing night vision. And these articles will be a bit easier to understand if you have the graphics to go along with them.
As I expected, we got an unusually large amount of comments, mostly critical, regarding the information we shared in part one of this series on night vision. Several manufacturers and dealers crabbed that I was: 1) Being too negative about the industry, 2) Using highly exaggerated specs for image intensifier tubes, thus making their rather ordinary night vision pieces look rather ordinary, 3) Overtly pushing the Dark Invader brand of night vision, and 4) Not playing fair. To the above I will briefly respond, then drop the whole thing. This column is not intended to be a pissing contest and allegedly we are all adults, at least biologically. Reference to above: 1) Probably I was too negative. I admit I'm rather cynical by nature and have little patience with those who try to take advantage of people who do not know too much about what they're buying and have to trust the vendors. I also am not fond of those who attempt to knock off a quality product and take advantage of a manufacturers' hard earned reputation by selling an inferior piece of equipment purporting to be an equal. The various vendors doing this know who you are and, to you, I offer no apologies. I did mention that there are many quality night vision devices available and certainly a number of quality firms out there competing in the marketplace who I am proud to call my associates. We all deal in a free marketplace, and the quality firms will eventually rise to the top. If you are one of them, you'll share my attempts to clean up the industry. If you feel threatened by my efforts to educate the consumers of our products, then maybe you're counting on their lack of knowledge to sell your products. I don't recall exactly how the story goes about the foo defecating, but it would be appropriate here.
Re 2) The specs I quoted were confirmed by top industry professionals as truly typical specs. In examining several data sheets for intensifier tubes, we found several that were better than the specs I used, and several that were worse. My references to commercial, military and hand select grades were taken directly from federal government standards, developed after millions of dollars and thousands of hours of research. No argument there.
3) If I seem too obvious in my enthusiasm for the Dark Invader, it is because I have found it to be a top quality, versatile, reasonably priced piece that is ideal for law enforcement. There is excellent factory and dealer support, a wide range of practical accessories specifically designed for police, and hundreds of satisfied professional users. In over sixteen years in this industry, I've sold night vision from most of the major manufacturers. The Dark Invader is the system I feel is the best equipment of its type available to the law enforcement community. Why shouldn't I be allowed to share a good thing with those who are spending our tax money (or deficit money) to buy it? And, anyway, I'm writing the damn article, not you. If you want to write an article pushing your equipment, be our guest. Just be sure you can back up your claims with proof. The guys reading this column are not dumb.
I'm not going to beat a dead foo. Please reread part one of this series in the last issue and decide for yourself. You pays your money and you gets your equipment. The purchasing agents who buy this stuff generally are pretty shrewd and do a commendable job of getting you the most for your money. They're not technical types, though. That's why I encourage the users, the technicians, to be in the procurement loop. A police department, on the budgets they give us anymore, can't afford to buy an expensive piece of equipment twice.
OK. We all see enough negative in this business, so the rest of this article will be positive. For the next parts, we'll discuss accessories for night vision, basic system configurations, and especially details relating to using night vision in front of film or video cameras. Pay attention. The majority of questions we get from night vision users will be answered here. All accessories, options and systems referenced may not be available from all manufacturers.
Most night vision pieces come standard with an eyepiece. A 32mm is typical. One popular brand does not include an eyepiece in the basic configuration, so be sure you cover this base if you are buying low bid. A quality eyepiece should be multi-coated, wide field, and focusable. Wide field means that you do not have to have your eyeball lined up precisely on the axis of the piece in order to see. If you've used certain scopes on a rifle, you know that if you're not directly behind the thing you can't see.
This, obviously, is what you don't want. It is better to see a piece in the flesh before you buy it as anybody can claim wide field - there is no standard or reference figures that mean anything here. Focusable means exactly that. If you wear glasses and your eyes aren't totally wrecked, you can focus the eyepiece (note we are not referring to the objective lens) to compensate for your less than perfect vision. This will let you use the night vision without your glasses, which is more comfortable for long viewing sessions. My glasses don't bother me with these things, but a few of my friends can't stand wearing glasses when they're using optics of any sort. I don't have any figures, but I imagine a focusable eyepiece could correct for at least minus 4 or 5 diopters. This is equivalent to moderate to severe myopia (nearsightedness).
Different eyepieces may be available. See part one last time for an explanation of why you might want a different eyepiece. There is one available for the Dark Invader that has ranging circles etched on the inside of the eyepiece. If using the standard objective lens (a 135mm), this special eyepiece will allow you to estimate with a reasonable degree of accuracy the distance from you to a man sized target. This is of primary interest when using the Dark Invader as a weapons sight. More on this later.
A neat goody, (would it be more professional to say "A very useful accessory"?) is a biocular eyepiece. Do not read this incorrectly as binocular. A biocular eyepiece replaces the monocular eyepiece usually supplied as standard and, as the name implies, lets you view intensified images with both eyes instead of just one. If you only have one eye you may skip the remainder of this paragraph. Typical bioculars are available in different sizes, ranging from 3 inches to six inches in diameter. A biocular lets you use both eyes to view from a distance of a foot or more. This is great for long viewing sessions, such as an all night surveillance where you would get tired holding the piece up to your eye for any length of time. The biocular, especially the larger ones, also are very useful for driving at night or piloting a boat through dark, maybe hazardous, waters. You can mount the intensifier on the dash or deck (more later) and watch it just as if you were watching TV. The biocular is also used where several officers must observe through the night vision at the same time. Try it, you'll like it.
Several mounts are available for night vision systems. Every scope that I know of comes drilled and tapped for a 1/4 x 20 tripod mount. As the name implies, you can use a standard tripod, either full sized or miniature depending on your particular application. If you do opt for a tripod, spring for a good one. A top grade tripod is not too much more expensive than a crummy one, and if you get a crummy one (with spindly legs) it will be such a pain that you'll probably never use it. For handheld use you don't really need any mount, but a pistol grip is an inexpensive accessory that makes life more pleasant. A pistol grip threads on and off the tripod mount in seconds. For the night vision scopes that are equipped with a spot illuminator, you can get a pistol grip with a trigger switch that will control the illuminator.
Other innovative accessory mounts include a car window mount that clamps down onto a side window in your vehicle and supports the intensifier. There are pieces of felt on the wide, flat clamps so they don't mangle the glass. The car window mount coupled with a biocular eyepiece is a very nice package for all night surveillances (the ones where you keep nodding off, and have to pee in milk bottles). An additional useful mount is a suction cup mount. This is a humongous suction cup that will suck up to any flat surface, and connects to the tripod mount. The suction cup is large enough to hold quite a bit of weight securely. There is a pushbutton to release the vacuum, and a gimbaled arrangement that lets you attach the thing at any angle and still keep the optical piece upright. The suction will hold for at least several hours, and probably a lot longer. You can use a suction cup mount to hold a night vision piece to the inside of a vehicle windshield for driving or flying (or spying) at night, or to hold the system firmly to the deck of a boat. Bogen makes a good one, or get it through your friendly neighborhood night vision dealer.
A telescope adapter is available for most pieces that will let you use your night vision behind a telescope. You can use a telescope as a very long range lens (see comments on this in part one), or maybe to view stars that are too dim for mere mortals. Obviously make sure everything in your proposed configuration is compatible and will fit before you start shelling out bucks.
Even though second generation, passive night vision works by amplifying existing light (as opposed to active night vision, which converts artificially induced infrared light to visible light), the passive devices are still very sensitive in the infrared portion of the spectrum. This characteristic is very nice for we, the people. Although most any night vision will work to some extent outdoors with existing ambient light, there are times where it would be nice to have some supplementary illumination. These instances might be when you are videotaping through the night vision and want to highlight a tag, or facial features. Or maybe you want to see into shadows. Or how about through a window into a darkened room? One job we assisted on once involved a night raid inside a large warehouse, and boy was it dark in there. We tried leaving some doors open to let some of the dark leak out, but no luck. Supplementary illumination was required.
The point I am getting to is that it is nice to have a way to generate some covert illumination for many of the scenarios where night vision is required. Infrared is perfect for this, as it is invisible to our eyes, very visible to night vision, easy, cheap, small and lightweight to generate. Infrared filters are available in different sizes to fit most standard police type flashlights, spotlights or floodlights. Dedicated filters are available off the shelf for Collins, Streamlight, Maglight and others. Consider a filter, especially if you already have a good light laying around. A potent light with the appropriate infrared filter will make your night vision see much better in dark places. Note that a filter does not make infrared light, it merely removes the visible components from the light generated by the source and lets the infrared pass through in peace. Therefore, it is necessary to get a filter of the proper wavelength for the night vision device you are using. Any old infrared filter will not do. Do not buy a filter from a camera store unless you know what to ask for. Merely requesting an "infrared" filter may not be good enough. Best to buy the filter either from the manufacturer of your light, or of your night vision.
An infrared filter blocks almost everything from passing other than infrared. This visible light does not just go off into never never land. It changes to heat. What I am trying to say is that a filtered light, especially a potent Collins CD12 or some such, will get very HOT when operating. Be sure the light has plenty of air circulation, and keep your fingers away from it. In general, if the filter gets hot enough to sizzle spit, it's too hot.
While we're on the subject of covert infrared illumination, how about marking a covert landing zone for a chopper? Covert signaling, perhaps ground to air, or vice versa?
Another very practical application for infrared, as viewed through a night vision device, are the use of miniature IR (from now on, I will use the abbreviation IR for infrared, OK?) beacons. IR beacons are available all over the place, inexpensively. A beacon is a very simple electronic circuit that flashes one or several IR LED's (Light Emitting Diodes). Usually they are encapsulated in black epoxy and have snaps molded in to clip directly onto the top of a standard 9 volt battery. The actual size of most beacons is about half that of the battery. No switches, controls or anything, just plug it onto a battery and it's working. You can't see anything happening, but through night vision these little goodies are blinking away. For a while we were making them up in house and using an old toothbrush container as a mold. Now we just buy them from guys who crank them out by the hundreds. You can order them with different flash rates so you can tell the difference between several units on the same job. A good alkaline 9 volt battery will usually run the things for a day or two. You also can get beacons that stay lit continuously, if your application requires such. An interesting property of the beacons is that the light they generate will penetrate a certain amount of clothing or other porous materials. If you put the beacon in your pocket it will still be visible (under night vision, of course).
What kind of havoc can we wreak with an IR beacon? Well, a typical application is for tagging friendlies in a night raid. You can mark packages, perimeters, landing zones, building entrances, etc. The first time we ever used them was on a job where we were surveilling a civil strike on an industrial job. We were on a water tower videotaping the strike activities through night vision. Our client had several K9's patrolling the perimeter, and frequently we didn't know precisely where the critters were. As we were trying to direct our K9 officers to certain trouble spots, it was difficult not knowing where they were in the dark. So the next morning I raided the local Radio Shack and threw together several IR beacons, which I attached to the dog's collars. Worked great. Later, on the same job, I dropped beacons inside the taillight lenses of a certain few vehicles we needed to keep tabs on. Through our night vision (from inside our vehicle) we could see them 5 or 10 blocks ahead - as long as nothing was in the way. I have since used the IR beacons for other covert night tracking operations. Their application is limited only by your imagination. Beacons are cheap enough for you to order several with your night vision scope.
A certain manufacturer who I am accused of plugging makes a more potent beacon in a package about 2/3 the size of a pack of cigarettes. This beacon has a clip to fasten it to a vest, harness, or belt. A different manufacturer has an IR beacon mounted in a baseball cap. Using watch batteries and miniature LED's, it easily would be possible to make up even more miniature packages than these for special applications.
Well, I'm going to wrap it up for now. My brain hurts, and I might need to use it again someday. There's a lot more we need to cover, but it will have to wait until the next issue. Stay tuned, as we will be getting into the all important videotaping and photographing considerations. And, please, continue with the feedback, be it assault or flattery. We appreciate constructive feedback - and criticisms are welcome also, as there is an ongoing requirement for paper to line the bottom of the parakeet cage.
We are in desperate need of ideas for topics for future articles, if there are to be any. I'm getting a bit burned out, as I contribute regularly to 13 various publications. Are these articles useful? Interesting? Boring? Entertaining? Please let me know. And, anyone who will be there, please look us up at Secret Service in May. Bye.
COPYRIGHT (C) FEBRUARY 1989 by Steve Uhrig, SWS Security.
"Please note: At the time these articles were written, SWS distributed the Dark Invader line of night vision equipment, manufactured by B. E. Meyers Company. We no longer recommend this brand of equipment or this company. Please see our links page for a link to another night vision supplier who we recommend."