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Part One of Two

Bumper beepers, bird dogs, tracking systems, direction finders, homing devices  - whatever name we know them by we're all talking about the same thing. Though the name is misleading (I'll explain later), around here we refer to the generic line of tracking systems as bumper beepers. Bear with me if I  unconsciously default to that name even where something else might be more  appropriate.

 What are we talking about? In a nutshell, bumper beepers are electronic  packages that assist you in following successfully a vehicle under  surveillance. A quality unit, specifically designed for covertly tracking a  moving vehicle, and operated by someone who knows what he's doing, will let you hang a considerable distance behind the target vehicle and tell you what direction to travel in order to stay behind the target. If you're an active investigator, in either the public or the private sector, pay attention here,  as these devices are one of the most useful investments your agency can make.  Here in part 1, we'll discuss some general aspects of bumper beepers and get  into practical hints concerning their operation. Part 2, in the next issue, will cover some technical aspects of bumper beepers, their care and feeding, more operational tips, and how not to get ripped off in buying one. As  always, part 2 will be influenced to some extent by reader feedback, so get your two cents in while you have the chance.

 How do YOU run a vehicle surveillance? Two investigators (money), two cars (money), two radios (money)? Somebody either within sight of the  target or both of you at either end of the street covering two possible  directions of travel? Target leaves and one of you has to turn around - what happens if you get stuck behind Mr. or Mrs. Elmer Grope or their grandmother, all of whom are going to cop a prima donna attitude that  the whole rest of the world is also going to observe the 20 MPH  residential speed limit? If the target is suspicious and uses the rear  view mirror that God and Detroit (or Japan?) gave him, you have your choice of either being made or dropping back far enough to where you might lose the target. Forget it also if you get caught at a long light, heavy traffic, complicated intersections, or if the target cuts behind the 7-11 for a few minutes to evade any possible tail.  Underground parking? Residential garage? Evasion? 90 MPH? I've been there too. Forget it.

 One of these days I'm going to compile and publish all the various  reasons (read EXCUSES) investigators give their clients why two professional detectives lost Mabel and her paramour for the fourth time. There will be a separate chapter for excuses followed by notice  that the retainer has been used up. The same book will also have a  section on dealing with clients who want to accompany you on the  surveillance.

 Bumper beeper packages consist of a transmitter which usually is  affixed magnetically to the car under surveillance, and a companion receiver which will tell you certain things about the conditions  between the transmitter and the receiver. Cheap units, usually the  imports selling for $500 to maybe $2500, will give you a tone of sorts which will tell you only if you are moving closer or further away from the target. Better units will indicate, by either a zero center meter or a series of lights, where the target vehicle is located in reference  to your vehicle. All units which indicate a bearing also will give you  a relative range.

 Properly applied and used, a real beeper (real meaning not a toy, which comprises virtually all of the cheapies widely promoted to private detectives) will let you stay far enough behind the target to be well  beyond visual range. By glancing at the receiver's meter panel every so often as you drive, you will know quite a bit about where the target is. If the meter is hanging around center, you're doing fine. If you start to see a definite indication of right or left, slow down and pay  attention to where the target might have made a turn. The closer you  get to the turn the more solid will be the left or right meter indication. No longer will you have to take a chance at a 4 way  intersection if you've lost sight of the target. If the target has  turned, you'll see it on the meter well before you get to the intersection. The meter will start pulsing to the right (or left), ending up pinned to one side or the other as you approach the turn. By the same token, if the target slides off behind a building or onto a side street in an attempt to evade surveillance, you'll see that in  enough time to take the appropriate action.

 With a beeper, you won't have to worry any longer if you get caught at  a light. If you're far enough behind the target to where he has time to park in a garage - no problem. With a bit of training, your unit will  take you right up to the door.

 Sounds great, doesn't it? As I mentioned earlier, vehicle tracking  systems are one of the greatest products ever developed for investigative use. We get several calls a week on our unit, and we're very enthusiastic about their capabilities. I hope to see some of the  mystique dispelled about these things, and see many more quality units  get into private hands. I don't work the street much anymore, but if I  did a bumper beeper and radios would be my trademark. In our field, as in most others, our equipment will tell the men from the boys.

 Modern electronic investigative goodies are nice, can save you  thousands of dollars and hundreds of investigator hours as well as  enhance your reputation as being the man who gets things done. If you were a high dollar client like an insurance agency or workman's comp commission, who would you be most willing to spend your investigative  dollars with? A bumbling loudmouth whose only piece of equipment is a gun, or a confident, well equipped agency who not only knows how to  apply technology to his trade, but offers a better work product with  fewer hours besides? This is a bit of a soapbox here, but I'm just sharing what I've heard from certain users of investigative services.

 Just owning the equipment doesn't do it though. To use an old analogy that's usually applied to weapons, just because I give you a violin  doesn't mean that you are a musician. The same holds true with bumper  beepers. The units work, and they work well, but a certain amount of  training and understanding of what the system is doing is necessary in  order to be successful in following a vehicle. I have a hard time getting this across to some of the investigators who call me and want a unit shipped overnight for a surveillance starting up tomorrow. You're NOT going to open up the box, read enough of our instruction manual to  figure out how to install the batteries and go out and follow a car around town.

 This thing will NOT tell you the direction to the transmitter. It doesn't know that. What it will indicate is the  direction(s) from which it is receiving the signal. Due to numerous  factors involving physics and radio propagation characteristics, you  can hope that the signal is arriving from the same direction as the transmitter - but you can't count on it. In just a second we'll get  into this, but the point I'm trying to make is that, regardless of what many salesmen of these devices would have you believe, a certain amount  of training is mandatory in order to get the most out of your new  tracking system. If you do buy a unit, plan on spending several hours reading not only the technical manual for the unit, but some information on radio direction finding in general. Knowing just a bit  of the theory of direction finding (which is what the bumper beepers  really do) will help you get much more out of the unit. If you're just  a grizzled old veteran of the street, don't be turned off by the  prospect of a bit of book work. Even a total ignoramus can soak up what he needs to know in an hour or so - and you wouldn't be here if you  weren't interested in expanding your knowledge of the field, so you  obviously aren't an ignoramus. To those who don't read my articles  though, it's a different story!

 If you buy a bumper beeper from us, you'll get copies of several pages  of mild theory on direction finding, as well as a comprehensive manual  on the operation of your unit. If you buy elsewhere, ask your supplier  to provide you with the same, or at least tell you where to go to find  the information. Don't try to use a tracking system, however, without  cracking the books or you'll be disappointed with the results and probably blame the equipment. Wherever you buy, though, feel free to  keep our phone number around if you'd like some handholding while you're getting started.

 Let's back away for a second and take a look at what we're doing with the beeper system. We have a relatively pipsqueak transmitter  (pipsqueak due to low power, less than optimum antenna and a crummy location buried underneath steel just a few inches from ground) trying to squeeze a signal into the twin antennas mounted on the roof of your  car. The problem is that the signal from the transmitter bounces off  every natural and man made object. Imagine a flashlight in a hall of mirrors. If the light is weak, and there's many mirrors to reflect the signal, you'll see hundreds of images. The only way to find your way to the flashlight is to walk towards the strongest reflection and hope you  see the flashlight from there. So it is with tracking systems. In busy  downtown areas, with many high buildings, overhead wires, and bridges,  you will have to settle for a bit less performance than if you were in  the suburbs or the country. Fortunately in the city you can usually hang closer to the target without being spotted, so the reduction in range is not too serious a problem.

 There is a partial solution to reflections. From here on out we will  refer to reflections by their proper name of "multipath". I'm not going to get too technical in this article, because the dry theory won't help you follow a car any better. Just try to follow along with what we do  cover, and that information will be plenty enough to get the job done.

 Most tracking receivers have an audio output. Our unit has an internal  speaker as well as a headphone jack. When you're experiencing multipath, you'll hear it as a raspy tone from the transmitter instead of a pure audio note. A pure audio tone is an excellent confidence that  you are hearing the beeper transmitter directly, and should be music to  your ears. The raspiness is caused by several reflections arriving at the antennas at almost the same time. You'll also notice the needle on the bearing indicator acting a bit squirrely. The overall average, as  shown on the meter, will usually be correct unless you're in a real difficult situation - maybe the target is over a hill from you, or you're in an artificial "tunnel" (at least as far as radio waves are concerned).

 If a hill is in the way the signal from the transmitter will go around it rather than through it. An artificial tunnel might be  a city block where high buildings surround you on all sides, and the  target is a few blocks off to one side. Again, picture a light shining  and all buildings and other objects as mirrors, which they are to radio  waves. In an artificial tunnel as we call it, the tracking system will  point to one end or the other, regardless of where the transmitter is actually located. Obviously if the signal is banging off buildings the best you can do is proceed in the direction of the strongest signal. From there you will have an excellent chance of acquiring the target directly. By the way, if you ever lose the target, have no idea where to start looking and you're starting to get worried, beat feet for high  ground - maybe a bridge overlooking the area. In most cases, if you don't waste too much time, you'll reacquire the target pretty easily.  And, if all else fails, head in the target's last known direction. Start driving in a grid pattern or an increasing spiral with your unit set to maximum sensitivity and you'll stand a pretty good chance of locking on to the target again.

 Don't treat bearings taken when you are not moving as gospel. Many, if  not most, of the multipath errors will average out with motion. Keep  moving if you hear a lot of multipath through the speaker of your  receiver (remember multipath sounds raspy). Your tracking receiver  should have some means of reducing receiver sensitivity. We have found  that better results are obtained with WEAKER - not stronger - signals.  A decent beeper receiver designed for investigative use will track accurately on signals that are inaudible through the speaker. So if  things get difficult, keep the sensitivity at the absolute minimum  necessary to get a definite indication on the meter. As long as the meter is reading, don't worry that you can't hear the beep through the speaker. Again, you'll have to use your unit enough to know how to tweak it for best results. In most cases when there are a lot of reflections the true signal will still be the strongest. So if you keep  the unit tuned down to where it only hears the strongest signals that will help keep confusion down from multiple reflections.

 If you're out of sight of the target, keep relying on the indications from the beeper receiver right up until you actually see the target. You will experience many false bearings towards the end with all the  strong signals. This makes it easy to overshoot the target. For some  reason, whenever I overshoot I get tied up in a maze of one way  streets, long lights, etc. By then the target is several blocks away  and there's a mad rush to reacquire and get back on track. It's more  professional to avoid this if you can. Vehicle tracking is like anything else in police work - hours of boredom followed by minutes of  pure terror.

 I'm doing this article backwards from the norm. Usually I cover the technical aspects first followed by operational info in part 2. With bumper beepers though, many of you are currently using the things so I  wanted to get some quick info out for you. Next issue will discuss the  several types of beepers, how they work and which one is right for you,  so if you're thinking of buying one either hang on until next January for part 2 or call us on the phone for a preview.

 There is one thing I won't hold till next issue though. Some tracking systems offer 180 degree performance and some offer 360 degree. What this means is that the 360 units will track on targets both in front of  you and behind you. The 180 degree systems will only indicate correctly on targets in front of your vehicle. This is not a problem for those of you that own 180 units. There are pros and cons to both. I'll tell you in a minute how to make a 180 unit function as a 360, for free. First,  though, realize the major differences between the two.

 If cost or covert operation is not a factor, buy a 360. A 360 unit  costs almost twice what a 180 does. A 360 unit also requires FOUR antennas to be mounted on the roof of your vehicle where a 180 only  requires two. Antennas will eventually need replacing just from ordinary wear and tear, especially if the unit is frequently moved from  car to car. The coax cables seem to go first, probably because  everybody squashes the cable when they roll the window up on it or close the door on it. I don't believe I mentioned yet that the antennas  are magnetically mounted on the roof of your car. The two antennas with  a 180 system mount left and right on the roof, with a single cable to enter the car on the driver's side. A 360 system needs four antennas,  mounted in a cross pattern on the roof (one left, one right, one front  and one rear). If you're covert, 4 antennas on the roof will not help.  Two antennas, with the 180 unit, don't help either but two are a lot  easier to swallow than 4. The reason I'm making a big deal about the antennas is that they are a major problem if the target would happen to  get a glimpse of your car. There are tracking systems with low profile antennas, which will be discussed next month, but they are VERY  expensive and the manufacturer could care less about any clients who  are not federal government with unlimited budgets.

 Don't kill yourself trying to spring the extra money for a 360 unit unless you really need that one feature of being able to track accurately both ahead of you and behind you. The 180 will do just fine if you understand what you're trying to do. If you're totally ignorant maybe a 360 would be worth the bucks - but remember what we said about  merely owning the equipment as opposed to knowing how to use it. Maybe  it's like the M-16 - cheaper to give the grunts an automatic weapon and zillions of rounds of light ammo than it is to teach them how to shoot a real gun accurately. In my business I can own anything I feel like  buying, and my own personal tracking system is a 180. That should tell  you something.

 If you have a 180 unit, the position of the meter (left or right) will  indicate in which direction you need to proceed in order to close in on the target. Remember, TURN INTO THE NEEDLE. You might write this in red  marker on the front of your unit. If the needle is pointing left, the box is telling you that the target is to the left of your vehicle. By  your steering left, the needle should approximately center as you get onto the right bearing. Now listen carefully - this next part is  important, especially for 180 system users. If you turn into the  needle, and the meter starts reading OPPOSITE of what you expect, meaning you headed left and the needle moved even more to the left rather than toward the center, then the target is BEHIND you. The meter  will be also be centered 180 degrees away from the target, but the  needle motion will reverse. If you always turn in the direction the  meter pointer indicates, and the needle moves BACKWARDS from the  direction you turn, then you are correct.

 This is very important. Understand this paragraph, as you will get really messed up if the target ends up behind you and you don't realize it. Also, by understanding this, you can make a 180 unit do virtually everything a  360 does, and save 4 or 5 thousand dollars in the process. One last time - turn into the needle. If doing that tends to center the needle  then you are OK. If you turn into the needle and it moves away from center then the target is probably behind you. This is another area  where experience is helpful. After a bit of practice all this will be second nature. Thank you.

 Any tracking receiver can be confused by other antennas or objects on the same roof as its antennas. If possible, try to keep the roof of  your car clear of other communications gear while you are involved in direction finding. Temporarily unscrew the CB antenna and your department's radio antenna if you can. Try to work off a portable for the duration of the surveillance. By the way, when you are temporarily removing antennas, unscrew and hide the microphone so you or somebody else doesn't accidentally transmit on a radio that is missing an antenna. If you're tracking from a vehicle that is equipped with a light bar, mount the antennas on top of it, or in front if you can't get on top for some reason.

 A certain private investigator of our acquaintance drives one of those  Morocco Mole cars with a plastic roof. Of course the magnet mount antennas won't stick to it so he does just fine with the antennas on the hood of the car. Looks funny but does the job. We tried attaching  the antennas to a metal plate and securing the plate with bungie cords to the rain gutters but we gave up on that and just stuck them on the  hood. Also, the antennas count on a large mass of metal underneath of  them for proper performance, so range will be considerably reduced if you try to mount them on a non metal surface. The same thing also goes for vinyl roofs. The antennas will work OK electrically, but the magnet  will not hold very well through vinyl. If the antennas slide around on  the roof you will get wrong bearings on your tracking receiver.

 In a two antenna system, one antenna should be marked "left" or coded somehow so you know which antenna goes on which side of the vehicle. Our unit has a label on them which always goes to the rear of the car. Do NOT get these reversed or the system will lie to you. Next month we will discuss initial setup and checkout procedures which will alert you  to backwards antennas before they are a problem. Read your  instructions. You don't have a 50-50 chance of getting them right. You have a 50% chance of getting them right and a 90% chance of getting  them wrong.

 If the antennas are backwards your bearings as indicated on the meter will be backwards. We had a case once where we did a leading tail and I  purposely reversed the antennas because I knew the target would be behind us all the time. Gimmicks like this are best left to  professionals though.

 You ought to know that cheap beeper units will vary their indication as the vehicle's battery voltage changes. This, of course, is assuming  that you are running the receiver off the cigarette lighter. Smaller  cars especially are affected by this. Even though the car's voltage is  allegedly regulated, and all manufacturers of cheap tracking systems will tell you that the car's electrical system voltage will not affect the unit, they are lying. In many cars, the voltage will increase with  higher engine revolutions, and vice versa. As you slow down for a light or whatever the engine will also slow down.. The voltage will drop  slightly and the unit may not indicate accurately. Solution? Use a top  quality tracking receiver. To be extra safe, our unit has provisions  for built in batteries, which will run the receiver for more than a day. This feature is primarily because our unit has been used from an aircraft with a 28 volt electrical system instead of 12 volts like a car, and we didn't want to fool with regulators. There are also certain situations where you might conceivably use a receiver portable, like on  a roof, where external power is not available.

 Well, that's it for this month. I know there are many things about  beepers that we didn't cover in this issue. Next issue we'll talk some  about actually attaching the transmitter to the car, which isn't always  as easy as you may have been told. We'll also discuss the legality of using a bumper beeper (not much of a problem), tips for effective  operation and a lot more theory about how the different types of  systems work. If you have a unit now and you have any questions about it, or it doesn't perform to your expectations, give us a call at (410)  879-4035. If you need to get one, we'd also like to hear from you. As our ads indicate, we do finance purchases of all our equipment so don't  be scared off by the initial cost. And thanks to everybody who has  taken the time to call with feedback on these articles. It's really appreciated. Let Al at the magazine or me know what you would like to  see covered in future columns. Let him know, especially, if these articles are helpful to you. The feedback is important to him as editor in helping us put together a quality publication that gives readers  their money's worth. This series of articles is currently required reading for at least one formal investigators' training course. We hope  that the magazine in its' entirety is informative and entertaining. Let  us know.

 Copyright (C) 1987 by Steve Uhrig, SWS Security.