- Nov 26, 2017
- US of A
10 Strategies For Communication Security – Don’t Betray Yourself When SHTF
March 11, 2020 by David Andrew Brown
Many preppers foresee the need for CB radios in a crisis, but, unfortunately, using a transmitter can bring an enemy or predator to your doorstep. If you use a radio to communicate with another member of your party, anything you say can be used against you. It is even possible to locate you by homing in on your signal.
Normally, the Citizens Band channels are chaotic, with everyone speaking at once, so that it is very difficult to understand what anyone is saying. In a survival crisis, however, expect the airwaves to be much quieter, as preppers won’t be burning up their batteries for idle chatter. It will be easier to listen in on a transmission.
The need for communication security
Any prepper who plans to use CB should be aware that each time he transmits, he advertises his presence, and if he is chatty, he will give away vital information, such as his location and plans, to anyone within range. “Anyone” may include an occupation force, a repressive government, or a band of looters.
Some preppers are concerned with having a retreat, away from it all, as a shield against whatever they see coming. Some foresee various possibilities, or scenarios, as follows:
In all of these scenarios, it is clear that the first line of defense is concealment. This means not only physical concealment but keeping a low profile by other means.
- Emergency Powers – During a crisis, the government proclaims a state of emergency, confiscating guns, stockpiles of food, and other resources.
- Foreign Occupation – A foreign power occupies the country, with confiscatory decrees as broad as the ones outlined above. Everyone must register with the occupying army and get an identity card. Anyone not complying with the decrees is subject to execution.
- Looters – During a crisis, outlaw bands prey on the survivalists who have stockpiled food and other supplies. Law enforcement is ineffective, and survivalists must defend themselves.
Few are aware of how vulnerable the use of radio makes them. The first, and obvious, fact is that anyone who monitors the bands becomes aware immediately that there is someone else out there. Because CB is short-range, anyone who hears a transmission knows that the sender must be within a few miles, or even within a few hundred yards.
What you say can give you away. Let’s eavesdrop on an imaginary conversation:
Mobile: “Hey, base, I’m coming in with the water.”
Base: “Okay. Come In by the Redman Road turnoff, and I’ll keep an eye out for you,”
Anyone who hears this knows that there are at least two people, that one is mobile and one is fixed, where the mobile person will be shortly, and what his cargo is. This sets up for either following or ambush.
Let’s eavesdrop again:
Mobile: “Base, I see three people in a truck coming down the road.”
Base: “Roger, I’ll send Chuck and Mike out to help. Are you still in the bushes behind the gas station?”
If the people in the truck have a CB, and are listening in, they know that they’ve been spotted, and how many they can expect to meet shortly.
Related reading: Detailed Strategies For Surviving An Ambush
Traffic analysis and communication security
The military and the intelligence services call this “traffic analysis.” It’s possible to learn a lot by listening in to unguarded conversations.
Direction-finding is another technique for locating a transmitter. As with traffic analysis, this complex of techniques finds wide use among the military. During World War II, for example, the Allies located and sank German U-Boats by monitoring their radio signals.
Radio-location depends on two techniques. Even the military’s classified equipment uses the same basic principles of signal strength and relative bearing. It’s possible to judge how close a transmitter is by the strength of the signal. Anyone who tries to find a transmitter can tell whether he’s getting closer or farther away by how loud the signal is.
Direction-finding by relative bearing depends on the fact that many antennas are directional: the strength of the signal relates to their position. Anyone who has used a television with a “rabbit ears” antenna knows how this works. Even certain types of outside antennas must be pointed toward the transmitter for the best reception.
Even an antenna not constructed to be directional receives better in one position in relation to the transmitter. A few tests with a friend operating the transmitter can show you what position gives you the best reception with your antenna. The results vary with the type of antenna, which makes it absolutely necessary to run tests on your own equipment.
Anyone who tries to locate a transmitter, unless he has very specialized equipment, will not know from which side the signal is coming, even when he finds the position that gives him the strongest reception.
He will, however, know that the transmitter is somewhere along a certain line. If he changes his position by a few hundred yards, he’ll find that the bearing is different, and he’ll be able to plot the bearings on a map, or even judge them intuitively, to find where they meet, which will tell him the location of the transmitter.
If there are two receivers, the task is easier and quicker. Each can “home in” on the transmission simultaneously with the other, which will be important if the transmission is short. Unless the person operating the transmitter is a “motor-mouth.” there may not be enough time for one person to move far enough to get a second bearing.
From this brief understanding of the ways in which your radio can be used against you, it’s possible to lay out some defensive measures to eliminate or reduce the risks.
Strategies for maintaining communication security
1. Keep radio silence.
This is the only sure defense. An eavesdropper can’t hear you If you don’t say anything. You can use your mobile phones for communication, stringing telephone wire from one site to another when you have enough wire is also an option. You can send someone to carry the message, which is usually practical because few messages are likely to be urgent.
Use the radio only for listening. You probably have already planned to do this, as in a crisis, you will depend heavily on the Emergency Broadcast System, shortwave, and other bands for your information. This has the advantage of saving your batteries, as listening uses far less power than transmitting.2.
2. Listen in
Listen aggressively, sweeping the various channels available to you. Someone may be transmitting near you, and you’ll want to have a chance to determine whether they are friendly or hostile, and what their intentions are.
Use the same techniques that might be employed against you—traffic analysis and direction-finding. If you have two radio sets, position them several hundred yards apart, and establish phone communication between them, so that the two operators can triangulate on a signal quickly.
Prepare in advance for some rudimentary direction-finding. Find out how directional your antenna is, and if you feel that it won’t do the job, construct a simple directional one. While antenna design is a very complex subject, and designing a technically correct one requires some mathematical calculations, you don’t have to do a perfect job. For your purpose, a cheap and dirty direction finder will do.
With a lot of planning and a little bit of luck, you'll be able to maintain total communication security by following and implementing these strategies.