An Agitator's Guide To Jamming.
Ok, so we weren't always the good guys....
CB radio was a fun pastime for myself and my teenaged cohorts in the mid 70s', and as young adults in the 80's and beyond. It was a time filled with general clowning around, games, pranks, practical jokes, DX talking, technical experimentation, chit-chatting, and many other interesting facets. Radio was fascinating for the wireless nature of the communications, the portability of the equipment, and for the diversity of the people who embraced this hobby. Most of the time, the great majority of people were decent and fun loving people, who contributed in a positive way to the overall experience. Unfortunately, with the laws of statistical probability being what they were, there were also a scattering of people, who had a particular personality type, that just didn't mesh well with our group of people. There were also those people who liked to cause trouble just for fun. Still others tried to control when and how our people operated. There were even those who looked for any excuse to challenge someone else to a physical fight. The latter two were especially prevalent in crowded urban/suburban areas, where most of the channels were filled with groups of various demographics, and cross channel interference was a common occurrence. Some of these undesirables could be ignored. But many others managed to cause enough of a problem that we developed an extreme dislike for them. When your dislike of someone grows to this degree, especially when you are young and impetuous, there is an almost overwhelming, insatiable desire to effect some sort of revenge, if for no other reason than, to make their lives as miserable as they have made ours. But while the desire for revenge was strong, there was also a desire to do so anonymously, so as to avoid a continual back and forth series of increasingly intensive reciprocal confrontations. It really wasn't necessary that the target know who was harassing him, or the reason why. Just the act of doing it, and witnessing their reaction, was enough to bring some sort of vindication to our damaged and emotionally immature egos. Also, truth be told, we wished to remain anonymous because we were a little afraid of going too far and getting ourselves in too deep with certain potentially unstable people.
Now some will invariably remind me that two wrongs don't make a right, the ends don't justify the means, and that my attempts to place these actions in the context of the time period in order to justify our admittedly bad behavior, do not diminish from the fact that, by stooping to their level, we were no better than the idiots we were targeting. Certainly that observation would reflect the opinion of a mature, rational, and emotionally secure adult. But remember, we were teenagers then, and true maturity was still a few years down the road. And I would by lying if I said that we didn't enjoy our little paybacks, if perhaps a little too much........
Now that I've gotten the background and official disclaimer out of the way, I will now get to the meat of this article and present the various jamming and agitation methods that were common in our local area, and the people and situations for which they were applied to.
Dead Key: Probably the most common method of jamming someone is to simply "dead key", or throw a "carrier". What that basically means, in non lingo-istic or technical terms, is to press the transmit button on the mic and not say anything. Your transmitter will send out a signal, but there will be no voice information carried. If your signal is strong enough, you can block someone else from receiving a weaker station, thereby preventing them from holding a conversation. This method can be very effective if you want to disrupt an individual or a whole channel, but you'll need a little bit of extra power, or a superior location to do it from, for maximum effectiveness. Downsides: A totally unmodulated carrier can be "talked through" by weaker signals with enough modulation. Also, switching to SSB and shifting frequency, will render the relatively narrow bandwidth carrier ineffective. The dead key was used by many different people over the years, due to its simplicity. But you have to be careful that an alert participant does not recognize your signal. If your signal has unique characteristics (Shifting frequency, an unusual or pronounced microphone or relay clunk, or an A.C. hum etc.) you could be identified.
Call Signals: A variation of the dead key. The difference is that the transmitter is usually a walkie-talkie. Many older 60's and 70's vintage 100 mW, and even some higher powered, walkie-talkies were equipped with either a Morse Code button or a "call signal" button. What this did was transmit a high pitched tone when activated. This method of jamming was effective if your target was a single individual who was close to you. Unlike a dead key, which was by nature quiet, the call signal used a strong and rather irritating tone. The obvious downside is that you had to be very close to block most of the target's receive. Another downside was that the target could move to a channel that your walkie-talkie didn't have. We used this method in the early days (When we still had walkie-talkies) against Zipper and other neighborhood bullies.
"Slideband": Basically this is similar to Dead Keying, but with a twist. While you are transmitting, you also rapidly swing a clarifier, or other frequency varying device on your radio, back and forth across the channel. This produces a sweep tone when heterodyning against the other signals on the channel, which can increase the annoyance factor. This was a method that I coined the name for around the time when I made the "Poor man's VFO" , and used it against some of the guys on Channel 18 during our feud with them in 1975. Downsides are the same as with dead keying, although it may be harder to identify a rapidly moving signal.
Bush Boogie: A low power battery powered transmitter placed in close proximity to a target's location with the objective of blocking their receive. Usually made from a small 100 mW walkie-talkie, although higher powered units have also been used. This method was effective against a single agitating troublemaker, by robbing them of the ability to hear other people. The downside to the Bush Boogie is that it's limited to a single frequency, but that is not a big concern if your primary goal is to keep the troublemaker off of your home channel. You will also have a finite amount of time before the batteries run down, and you will have to retrieve the unit to change them, which increases your risk of getting caught.
Broadband Noise Generator: An especially insidious form of a "Bush Boogie". But instead of a single channel transmitter, a circuit which produces a broadband noise is used instead. Like a normal "Bush Boogie", it is low powered and must be placed close to the target's location (The closer the better). The really cool part is that it does not transmit an obvious carrier, but rather a high noise level which will be heard on all channels. Because of the nature of the interference, the target may not even suspect that he is being jammed, and may think instead that he has local noise issues. If the level of noise is high enough, the target won't be able to hear anything below very strong local signals. The best part is that no matter how many channels the target has, the noise will be there, and it will eventually drive him crazy. The only downside is, like the Bush Boogie, that you will eventually have to retrieve the unit to change batteries.
Playing Music or Other Sounds: This is a more effective form of jamming than a simple dead key. Since you are applying modulation to the jamming signal, you prevent people from talking underneath the carrier, and the extra bandwidth taken up with modulation makes an SSB escape less effective. One of the most appealing aspect of this method of jamming is that it allows you to be somewhat creative in the material you broadcast. It could be as simple as just playing the broadcast radio, or you could be a little more innovative and create a tape of some off the wall sound effects or themes. One of the more favorite signature sounds used by guys like Steve and Jimmy was a recording of "Big Ben" striking 12:00, and the theme from the TV show "The Addams Family". Another clever use of recording was the playing of telephone company error messages ("The number you have reached..... is not in service..."). What Jimmy used to do was take the tape recorder in his car and park somewhere, and then play those recordings. People assumed that because they were telephone related messages, that the jammer was operating from a base. The downside of this type of "inventive" jamming was that if you were ever identified, you could no longer use the same techniques, as they would become your "signature". In fact, there were certain people would often imitate another's signature jamming method, in order to deflect blame to that person.
Voice Impersonations: Not so much a jamming method, but rather a method of agitating a particular person or group. In this case, someone will disguise their voice in order to create havoc. Usually the agitator will pick a voice impersonation that they're adept at, and then perform the CB equivalent of a Friar's Club roast to one or more of the regulars on the target channel, in the hope that they'll become angry and unglued. Other times the agitator just wants to play clown, and only seeks the resultant attention. The downside to this method of agitation is that you run the risk of being recognized, as even when you disguise your voice, certain vocal markers can show through. Also, you cannot use that particular impersonation anywhere else, or you risk exposing yourself. This was another favorite method of agitation for Jimmy.
Voice Alterations: Today, there are a number of electronic means of altering your voice to make it sound much different than it normally does. But back in the 70's, the most popular method of voice alteration was through use of a reverb or echo device. A combination of a Voice Impersonation along with a reverb, and you could be the next "Invader", or some pugnacious creature from the underworld. Again this was used more for interactively agitating a channel, (Which was usually a lot more fun) rather than simply jamming it.
Sideband (SSB): Single Sideband transmission is a method of transmitting audio information only, without the need for a carrier. Because it requires a special receiver to demodulate properly, it cannot (normally) be received properly on an AM-only radio. On an AM rig, SSB transmissions sound like gibberish, and the nature of the sound is such that they become irritating after listening to it for a while. This makes SSB a very effective jamming technique, especially when the group you are targeting only have AM rigs. But usually we would use this technique, not as an offensive jamming technique, but as a defense against other jammers who would normally try to agitate us by dead keying or playing music. Switching to SSB in this manner, had a twofold benefit. First, it allowed us to shift frequency away from the jamming carriers, thereby allowing us to continue communicating even over much stronger signals that would have blocked us on AM. Secondly, the gibberish noise of the SSB transmissions would often drive away the agitators. If they couldn't understand what we were saying, they couldn't interact. Since SSB signals are not steady and vary with audio amplitude, they are also more difficult to track.
One of the biggest objectives of a jammer, is to not get caught. Anyone who is serious about finding a jammer is going to employ some sort of DF technique to attempt to identify you. So to be an effective jammer, you must be able to thwart, or at least slow down, the tracker's ability to home in on your signal. Here are some ways to accomplish this:
Varying Signal: Generally speaking, it's never a good idea to jam from your base station. It's far too easy for someone to identify you, especially if you have neighbors who are also on CB, and could immediately recognize that pegged S-meter reading. It only takes one of them to speak up and "dime you out", to put your anonymity in jeopardy. But if you must use your base (Like if you're not quite old enough to drive yet), there are a few things you can do to throw people off the trail. One of the best ways to accomplish this is to vary your signal. If every time you key up, your signal is different, it impedes efforts to localize you. Some methods to vary your signal include variable wattage controls on your radio, alternating use of an amplifier, and moving a directional beam. A combination of these techniques can actually fool others into thinking you are transmitting from a moving mobile, rather than a fixed base station, especially if you randomly vary your signal while you are keyed up.
Coordinate With Others: A very effective detection avoidance technique is to have several friends take part in the action. If each time the jamming signal is transmitted, a different person from a different location is doing it, it becomes especially confusing to track down. This requires planning and the careful ability to not key at the same time, which will expose your ruse.
Brevity is a Virtue: The longer you transmit, the greater your chances are of being found. So limit your jamming to short busts which coincide with your target's transmissions. Fight the temptation to just lock the mic on and watching a half hour of TV.
Operate Mobile: This should be pretty obvious. When you operate mobile, you can transmit from many different locations, or even while moving. You can also take your signal to the area you want to target for the maximum effectiveness. But be careful. If you get too close to your targets, you may be spotted, and summarily chased. I preferred to park on a limited access hill overlooking the target area, while running extra power. The signal was as strong or stronger than a base in town, and trackers will race around that end of town with signals in the red, assuming a local base, while you watch from your perch on the hill laughing. If someone does get close, you can always remove your antenna, slip away, and move to another place and start over.
Remote Transmitter: Ok, this is probably a bit extreme for the average CB'er, but it is possible to remotely control your base, or a parked mobile, by linking the audio and transmit control over another frequency. Basically this is analogous to "crossband repeat" ham rigs that simply repeat what they receive on one frequency band out onto another. You could use ham, FRS, or MURS bands as the "link" frequency and, with a little creative interfacing, you're on the air. But this might be a little over the top unless you just enjoy building strange gadgets. The primary benefit of this system is deception. You can appear to be in two (or more) places at once. You can be talking "innocently" from your base, while you jam the same channel from a remote location. "Hey, the jammer can't be me, I'm right here!". The downside is risk of exposure. If you park your mobile to use as the remote and it is discovered, it is likely to be vandalized.
Ok, so now that I've covered some of the various jamming techniques, I guess it's only fair to give equal time to countermeasures. In the back and forth, cat and mouse arena of CB feuds, it is likely that you'll be the object of someone else's jamming attempts at some point. So while you plan your revenge, it's helpful to remember, that the goal of a jammer is to disrupt the normal channel activities. The more you can give the appearance of being unaffected, the less satisfaction the jammer will get. Perception is key. The jammer may be totally blanking your receive. But never let on that fact. In fact it is better to ignore the jammer as much as possible. Attention is what they want, and by denying it to them, you ruin their "fun". So with this in mind, here are some techniques to thwart, or reduce the effectiveness of a jammer, or at least make it appear that way.
Listen Through the Dead Key: You find yourself the victim of someone throwing a strong dead key. Now what? Well, like I mentioned before, a dead key can be talked through with weaker signals. You may have to turn up your volume control or move your clarifier a bit to hear them better. But it's possible. The most important thing to remember is no matter how painful it is to pick out other stations under the carrier, do not acknowledge that the carrier is affecting you. Just try to carry on like it is business as usual.
Beams and Power: This one is so obvious, I shouldn't even have to mention it. Obviously, if you and the others on the channel have some additional power on tap, that can help to override the jammer(s). The same can be said for a beam. Other than helping your signal override the jammers, a beam can help you to localize the jammer. You can also use the back rejection of your beam to null out an otherwise stronger jamming signal, in order to hear weaker desired stations in a different direction.
Use SSB: If the jamming carrier is especially strong, and there is no practical way you could continue to have a conversation, a switch to SSB and a shift of the clarifier (You DO have an unlocked clarifier right?) away from the carrier (Usually + on USB and - on LSB), will regain much of your receive ability. While the act of switching to SSB acknowledges that the jammer is affecting you, once you are there, he won't be. Since the sound of SSB on an AM-only rig is annoying, the jammer will hopefully quit after a fairly short time.
Use The Phone Luke: Another innovative trick is to pick another person, with whom you are talking to on the channel, and call them on the phone without saying anything. Then simultaneously continue your conversation over the radio, and over the phone. The jammer might very well have your receive totally closed down. But thanks to the phone link, you can continue your conversation as if you were unaffected by the jammer. The tough part is that you are basically limited to a 2-way only conversation. It's helpful to have all of your friends on speed dial....... A variation of this is to talk on another radio band simultaneously where you can have more than a simple 2-way conversation. Of course, if you and all of your friends are also hams, why are you wasting time dealing with this nonsense? Unless, of course, you enjoy it.
Change Frequencies: If you reach the point where you can no longer pretend that the jammer is not affecting you and your friends, and other evasion methods have not proven effective (At which point you should probably be looking out the window), your last resort, if you want to continue using your radio, is to change frequencies. Of course, if you simply announce a move to another channel, the jammer will just follow you. The best case would be if you and your friends all have some out-of-band channels to go to, in the hopes that the jammer does not. If you can't utilize out-of-band channels, then you can at least gain some temporary relief if you have a code for which channels you will go to. It will only take a minute or two for the jammer to spin the dial and find you again, so it's to your advantage to have a plan in place ahead of time on where to go next, when he finally shows up again. An alternative would be for your group to scatter among several channels. That way a single jammer cannot affect everyone at once. Hopefully, the jammer will become tired of chasing you all around, before you get tired of running.
D.F. The S.O.B.: This may not be necessary for a "once and done" jamming situation. But if the jamming starts becoming a regular occurrence, it would probably be in your best interest to locate him. Use of Direction Finding Techniques will help you achieve that goal.
Expose the Jammer: Most jammers wish to remain anonymous. Usually this is so they can hypocritically complain about other jammers, while claiming to be above these activities themselves. Or they may be "Jekyll and Hyde" - type people who enjoy jamming, but still want to remain in good standing with the locals. Some are simply gutless and anti-social. But whatever the reason, once you finally locate the jammer, find out as much information that you can (Name Address, Phone number, etc.) and then summarily broadcast it. Unless the jammer is truly sociopathic and doesn't care what others think about him, he will stop jamming, although he will likely become belligerent and deny that he was the responsible party, even in the face of all the evidence that you have gathered against him.
Localized Interference: If you suspect that you are the target of a "Bush Boogie" or Noise Generator, you can attempt to locate them. Remember, they are low powered, so they will be very close to your location, and likely on your property itself. Bushes, shrubs and trees make good hiding spots for these devices (Hence the name "Bush Boogie"). The easiest way to locate such a device is with a handheld radio with an "S" meter. Just walk around until the meter deflects the farthest, and you will probably spot it. Once the device is located, you now have a few interesting options. You could simply disable the device or, for a little sadistic fun, you can leave it in place and wait to catch the people who left it when they come to replace the batteries. If you have no way to frequently monitor the location, you can leave them a little surprise. Place a rat (or bear) trap under or next to the device. When the owner comes to retrieve it (Which will likely be at night) he might not see the trap and well.......
This pretty much concludes the technical side of jamming and agitation. Be sure to check out the companion article "Agitator Chronicles", for a closer look at some of the people who I knew who were involved with jamming and agitation activities and related stories.