Learn: from zero to the first signal
You do not need a radio, a license, or money to start listening. You need curiosity and someone to explain things clearly. There are 14 short guides, about 83 minutes of reading in total, in the order I wish I had learned them.
To begin
What is radio listening
Listen to radio out of interest in the signal itself: who is transmitting, from where, and how it arrived. You can start today, in your browser, without buying anything.
Spectrum map: who lives in each band
From long waves to 1090 MHz: what to hear in each slice of the spectrum and at what times it is worth looking.
How to use a WebSDR
A step-by-step guide to KiwiSDR, OpenWebRX and classic WebSDR: tuning, modes, filters, zoom and the etiquette of using someone else's radio.
How to read the waterfall display
The colored screen of receivers shows frequency, time and strength. Each signal type has a distinct look, and you can recognize it before listening.
How to become an amateur radio operator in Brazil
COER, classes C, B and A, Anatel online test, callsign, what each class can do and where LABRE and clubs help.
What you can listen to and what you can publish
Listening and sharing are different things. What Brazilian law says about telecommunications privacy and what is public by nature.
Glossary
Most used Q Code, RST, SINPO, dB, SNR, UTC, grid locator and the other terms that appear in guides and on the air.
To go deeper
Propagation without mystery
Ionospheric layers, day and night, solar cycle and SFI and Kp indices, with Brazil and the southern hemisphere as a reference.
Shortwave DX
Broadcast bands in meters, schedules in UTC, the SINPO code, and how to request a QSL card from a broadcaster.
FT8 and WSPR: weak signals crossing oceans
How the 15-second FT8 cycles work, what each message says, WSPR as a propagation probe and the PSKReporter map.
Aircraft on the radio: ADS-B and air band
What an aircraft transmits on 1,090 MHz, how far it can be received, how an RTL-SDR decodes it, and how to listen to the voice in AM.
DMR and digital voice
Time slots, color code, talkgroups, repeaters and hotspots: how DMR works and how to listen to the network before getting a radio.
From space: ISS, radiosondes and satellites
APRS and SSTV from the Space Station on 145.825 and 145.800 MHz, weather balloons from 400 to 406 MHz, and what is left of weather satellites.
First receiver: RTL-SDR
How to start spending little: what the RTL-SDR is, a simple dipole, the programs, what it hears and why antenna and noise rule.