01

The short answer

Begin with receive-only work: install the HackRF tools, verify the device, observe known public signals with conservative gain, then decode a lawful broadcast such as ADS-B where permitted. Do not transmit until you understand frequency authorization, power, antennas, filtering and the specific regulations that apply in your country.

New software-defined-radio users who want a practical, safety-first path from device setup to spectrum viewing and public-signal decoding.

02

Before you start

Have these basics ready before choosing parts or flashing firmware.

  1. A genuine or compatible HackRF One, shielded USB data cable and an antenna intended for the receive band.
  2. A computer or Raspberry Pi 5 with supported SDR software and enough storage for short captures.
  3. A local legal reference for spectrum reception, recording, privacy and transmission.
03

Progress by risk, not novelty

Spectrum viewing: You are learning center frequency, sample rate, gain and noise floor.

Public broadcast decoding: The signal is intended for reception and local law permits it, such as ADS-B in many jurisdictions.

Offline analysis of your own signal: You generated or captured it lawfully in a controlled setup.

Transmission: Only after confirming authorization, band plan, power, filtering and a safe test arrangement.

04

Install and identify the radio

Install libhackrf/HackRF tools from a trusted package or the official project instructions, connect directly by USB and run the device-information command. Record firmware and host-tool versions before updating anything.

  1. Use a short, shielded data cable.
  2. Do not update firmware merely because reception is noisy.
05

Use an antenna for the band

A wide tuning range does not make one antenna efficient everywhere. Choose a receive antenna designed for the target band, inspect connectors and place it away from the computer and noisy switching supplies.

  1. Never transmit into an absent or unsuitable load.
  2. Start with receive-only adapters and no amplifier.
06

Learn frequency, sample rate and gain

Tune to a known local broadcast or other lawful reference signal. Use the smallest sample rate that covers the signal plus context, increase gain gradually and distinguish a raised noise floor from a stronger signal.

  1. Change one gain stage at a time.
  2. Avoid clipping from strong nearby transmitters.
07

Make a short, documented capture

Record only enough I/Q data to reproduce the observation; files become large quickly. Name the file with center frequency, sample rate, gain, antenna and timestamp, and avoid retaining content you are not permitted to record.

  1. Check free disk space first.
  2. Keep an unmodified reference capture.
08

Decode a public broadcast

Where lawful, ADS-B is a clear first decoder because the project tooling and message format are widely documented. Use dump1090 with supported input, compare received aircraft against a second public source, and treat missing messages as normal reception limits rather than proof of absence.

  1. Do not publish sensitive receiver location without considering privacy.
  2. Do not use reception as a safety or navigation service.
09

Analyze your own OOK test signal

Use Universal Radio Hacker on a signal from your own authorized low-power device or a provided sample file. Inspect timing and modulation offline; do not replay third-party controls, alarms, access devices or rolling-code systems.

  1. Keep analysis and transmission physically separated.
  2. Document authorization and test equipment.
10

Safety and legal notes

Radio law varies by country: reception, demodulation, recording and disclosure can each be regulated, and the HackRF can transmit across frequencies where unlicensed operation is prohibited. This guide is receive-first and does not authorize interception, jamming, impersonation or transmission; consult your national regulator and band plan before any over-the-air test.

  1. Never interfere with emergency, aviation, navigation, cellular or safety-of-life services.
  2. Do not decode or disclose private communications.
  3. Use attenuators, filters and a shielded test setup when learning transmission under lawful authorization.
  4. PortaPack MAYHEM adds convenient transmit-capable features but does not change legal limits.
11

Troubleshooting

The host does not detect HackRF. Check cable, USB port, permissions and libhackrf installation; run the device-info tool before opening a GUI.

The waterfall is all noise or overloaded. Reduce gain, move away from digital noise, use a band-appropriate antenna and add filtering for strong nearby signals.

dump1090 shows no aircraft. Confirm local ADS-B frequency, antenna suitability, line of sight, input support and command parameters; do not compensate by transmitting.

12

Next steps

Keep the next experiment small and reproducible.

  1. Verify the device with HackRF tools.
  2. Observe one lawful reference signal without recording.
  3. Decode ADS-B or analyze a provided sample file, then write down the exact receive settings.