Why does voice radio come first?
When power, telephony, and the internet fail at the same time, voice radio tends to keep working. It depends only on a battery, an antenna, and line of sight between the person transmitting and the person receiving, with no intermediate infrastructure.
During the 2024 floods in Rio Grande do Sul, this made a concrete difference: amateur radio operators relayed more than four thousand distress calls in the first days of the crisis, and in Muçum, HT Radio sets linked to repeaters were, for a period, the only fully functional means of communication in the city.
The PACE model
PACE organizes a communication plan into redundant layers, each acting as a backup for the previous one when it fails:
- Primary: voice over VHF/UHF (unlicensed, CB, and amateur radio).
- Alternate: LoRa and Meshtastic.
- Contingency: Wi-Fi combined with satellite links.
- Emergency: the SOS button on a dedicated tracker.
Voice occupies the primary layer because it is the simplest technology to operate and the most independent of infrastructure among the four.
The three categories of radio
In Brazil, using a voice radio means choosing among three categories, each with a different balance between ease of use, range, and regulatory requirements.
| Category | Band | What it takes to operate | Role at Tridecs |
|---|---|---|---|
| Unlicensed (walkie-talkie) | UHF, fixed channels | Type-approved radio; no registration | Community and leaders at forward posts |
| CB Radio (PX) | 26.960 to 27.860 MHz (HF) | Free registration in Mosaico + type-approved radio | Base station; contact with highways and truckers |
| PY (Amateur Radio Prefix) | Several bands, from HF to microwave | COER certificate + station license | Strategic coordination and emergency networks |
Unlicensed radios are the entry point: pre-set channels, simple pairing, and no registration required, but short range and a ban on using amateur radio sets outside their own band.
CB radio has emergency use as an explicit purpose in Anatel’s regulation, which lists disasters, fires, floods, and accidents among the service’s intended uses. As a Restricted Radiation service, it is exempt from individual licensing.
Amateur radio offers the greatest range and technical flexibility, in exchange for a more demanding qualification — the COER and a station license. In return, regulation gives emergency communications priority over any other traffic in the amateur radio service.