Considerations for group comms in a non permissive environment.
Before we get into anything too deep I would like to start with a few key points to remember. First, just having comms, even a few Baofeng radios or walkie talkies puts you in a far better place than a group without. Second, civilian accessible encryption like P25, DMR, etc, will slow down someone from intercepting your messages. But it will not stop someone with an SDR and enough time on their hands from decoding what you have said. Using predetermined code phrases and randomized callsigns can be harder to decode than most civilian encryptions. Third, reducing your RF footprint is extremely important, far more important than encryption, especially if you are in an area or situation where you
absolutely cannot be found. You can reduce your RF footprint by making short transmissions, using directional antennas, and only transmitting away from an area you will spend a long time at. By following these suggestions, it will be far more difficult for an opposing force to directly find your location. Fourth, and last for this iteration, is to train with your comms like you would everything else. Make sure you have extra batteries, and ensure that everyone knows how to operate their radio and change frequencies manually. Test your comms in real world environments, learn which antenna's work best with your kit and radio, how terrain affects your transmission and reception of signals, and make sure you have predetermined frequencies to use.
Abbreviations and other term definitions.
RF - Radio Frequency
P25 - P25 is a radio mode that allows for large radio traffic on a few frequencies, it also allows encryption of that traffic. It is used by law enforcement, EMS, firefighters, along with some businesses.
DMR - DMR stands for Digital Mobile radio, it is another commonly used digital mode that allows for some encryption as well as text like messages between radios. It is more commonly used in commercial or amateur radio settings.
SDR - Software Defined Radio, these devices allow you to have a visual look at what is going on in the RF spectrum. You can record entire swaths of frequencies to review at a later time. Many programs enable you to decode and listen in live to P25 or DMR radio modes. They can even be used to direction
find or track aircraft. SDR's are a topic that will be revisited at a later date as their use can be extremely valuable or detrimental to you depending on the situation.
Directional antenna - These antenna most popular of them are called Yagi antennas have multiple elements allowing you to pick up a signal that is farther away given you are pointing it in the correct direction. When transmitting with a Yagi antenna your signal is sent with more strength in the direction it is aimed. Try to think of a directional antenna as using a laser pointer vs using a lantern.
Author: E. Turner