Radio Terms

Analog & Digital:

There are many ways that radio can be used to communicate. In general terms, we can think of them as different “modes” of communication. There are two main voice modes:

• Analog - The voice or data is directly modulated using analog means. This is the most common method used on all bands and does not allow for any means of encryption by the radios being used.
• Digital - The voice or data is encoded digitally before modulating it using analog means for transmission. As a result, encryption/decryption of the voice or data is possible by the radios. This is common in military and newer “trunked” law enforcement radios. In the civilian world, voice encryption only available on VHF/UHF bands such as 2M & 70cm (and not legally allowed to be used). Encryption is also possible using pure data-only modes such as Meshtastic.

Simplex vs Repeaters:

If you and another person have radios and directly talk to one another, this is called “simplex”. In this, you’re talking to one other, just like if you were face-to-face. However, this method has limitations.

Let’s say there’s a mountain between the two of you. Unless you’re using very specialized radio methods (NVIS), you can’t talk to one another over radio. To accomplish this, you need something in between the two of you to make this connection “over” or “around” the mountain for you. To do this, we use repeaters.

Repeaters simply do what the name implies - they take in a message and “repeat” it back out.