Basic characteristics - voxo22/hackrf-spectrum-analyzer GitHub Wiki

Basic characteristics

This page lists the main configurable ranges and features. Some values apply only to live sweep mode, some only to I/Q replay or the time-domain I/Q analyzer.

Live spectrum sweep

These options apply to the main spectrum analyzer when HackRF sweep is running live.

  • Sweep frequency range: 0 - 7250 MHz
  • Full frequency range sweep time (0 -> 7250 MHz): approx. 900 ms typical
  • Fastest sweep time for narrow ranges up to 20 MHz: approx. 2.5 ms typical
  • Shortest equivalent FFT-bin acquisition time: approx. 0.4 µs
  • Usable dynamic range: approx. 70 dB
  • Resolution bandwidth (RBW) presets for live sweep: 3, 10, 20, 50, 100, 200, 500, 1000, 2000 kHz
  • Manual/compressed sweep ranges: multiple displayed MHz ranges can be entered as comma-separated intervals, for example 920-960,1805-1880,2620-2690
  • Frequency shift presets: 0, -120 MHz (SpyVerter/upconverter), 9750 and 10600 MHz (Sat TV LNB downconverter)
  • Frequency selectors and range entry use shifted display frequency when Shift is active; HackRF tuning remains internally unshifted
  • LNA gain: 0 - 40 dB, step 8 dB
  • VGA gain: 0 - 62 dB, step 2 dB
  • Combined gain control: 0 - 100 dB visual scale, mapped to LNA/VGA values
  • RF amplifier switch: approx. +14 dB
  • Bias Tee switch: 3.3 V antenna/external-device power
  • No DC switch: spur/DC artifact suppression for live and replayed spectrum
  • Adjustable amplitude offset: -20 to +20 dB
  • Power calibration factor for total power / power flux density display: 25 - 65

Spectrum chart display

These options apply to the main spectrum chart. Some traces depend on live sweep or replay data availability.

  • Chart types: realtime, peak, average, max hold, persistent
  • Peak and max-hold markers can be switched independently
  • Marker count: 1 - 5
  • Chart line thickness presets: 1, 1.5, 2, 3 px
  • Optional spline interpolation
  • Peak fallout time presets: 1, 5, 10, 20, 30, 60 s
  • Peak fall threshold presets: 0, 2, 5, 10, 15
  • Peak hold time presets: 0, 1, 2, 5, 10, 30, 60 s
  • Persistent decay rate presets: 1, 5, 10, 30, 60 s
  • Average iterations presets: 20, 50, 80
  • Average display offset: -10 to +10 dB
  • Frequency allocation bands: loaded from user-editable CSV files in the freq folder
  • Mouse delta measurement: CTRL + left mouse drag measures frequency and amplitude difference
  • ALT while dragging bypasses snap to rounded frequency or compressed-range boundaries

Waterfall

These options apply to the waterfall under the spectrum chart.

  • Waterfall display can be switched on/off
  • Waterfall palette start: -130 to -80 dB
  • Waterfall palette length: 10 to 90 dB
  • Waterfall speed: 1 - 10
  • Optional timestamp display
  • Optional information box display
  • In replay mode the waterfall can show a green progress bar and trigger/event markers

Spectrum and I/Q replay

These options apply when opening recorded files with REPLAY.

  • Native HSR replay: replays spectrum and waterfall data recorded by the analyzer
  • HSR contains spectrum data only; it does not contain I/Q samples
  • I/Q WAV replay: stereo PCM I/Q WAV files, 8-bit or 16-bit samples
  • Raw I/Q PCM replay: raw PCM files with sample rate and bit depth identified from file name
  • I/Q replay spectrum RBW presets: 0.05, 0.1, 0.2, 0.5, 1, 3, 10, 20, 50, 100, 200, 500, 1000, 2000 kHz
  • I/Q replay can be used for time-domain analysis, demodulation and channel selection
  • I/Q replay audio demodulation modes: AM, FM
  • I/Q replay audio volume: 0 - 100 %
  • I/Q replay burst detection option
  • I/Q replay transmit option through HackRF, with optional custom TX center frequency
  • I/Q replay TX power slider: 0 - 47

Time-domain I/Q analyzer

These options apply to the separate I/Q analyzer window, either with live HackRF I/Q or with I/Q replay input.

  • Live I/Q sample rate presets: 2, 3, 4, 5, 6, 7, 8, 9.142857, 10, 11, 12.5, 13, 14, 15, 16, 17, 18, 19, 20 MS/s
  • Time view presets: Custom, 1k, 2k, 4k, 8k, 16k, 32k, 64k, 128k, 256k, 512k, 1M, 2M samples
  • I/Q analyzer LNA gain: 0 - 40 dB, step 8 dB
  • I/Q analyzer VGA gain: 0 - 62 dB, step 2 dB
  • RF amplifier switch
  • View modes: Wideband, Narrowband
  • Narrowband channel bandwidth presets: 12.5 kHz, 25 kHz, 100 kHz, 200 kHz, 500 kHz, 1 MHz
  • Narrowband output rate presets after channel filtering: 48 kS/s, 96 kS/s, 192 kS/s, 250 kS/s, 500 kS/s, 1 MS/s
  • Zoom/channel presets: Manual, Wide pulses, GSM 200 kHz, NFM 12.5 kHz, NFM 25 kHz, WFM 200 kHz, FM RDS 250 kHz, Wide 1 MHz
  • DC offset avoidance: Auto in Narrowband mode; selectable low-IF shift in Wideband mode according to sample rate
  • Display overlays: envelope, FSK/FM deviation, burst detection
  • Auto level option for time-domain display and downstream recording/demodulation
  • Audio demodulation modes: AM, FM
  • Audio tone cutoff range: 3 - 22 kHz, default 16 kHz
  • Audio volume: 0 - 100 %
  • Burst trigger pre-history presets: 10 %, 25 %, 50 %, 75 %
  • Burst trigger threshold slider: 1 - 181, lower value is more sensitive

Signal analyzer

These signal-analysis modes are available from the I/Q analyzer.

  • Generic QAM
  • FM RDS
  • DAB
  • DVB-T 8 MHz
  • DVB-T2 8 MHz
  • ISM 868
  • GSM 2G
  • UMTS 3G
  • LTE 4G
  • NR 5G
  • Bluetooth
  • Wi-Fi

See also: Signal analyzer.

Recording

These options apply to spectrum, screen/video and I/Q analyzer recordings.

  • STATS CSV logger interval presets: FRAC, SEC, MIN
  • Native HSR spectrum DATA recording FPS presets: FULL, 90, 60, 30, 15
  • Main-window video recording area presets: SPECTR, SPEC+WF, FULLSCR
  • Main-window video recording format presets: GIF, MP4
  • Main-window video recording resolution presets: 360p, 540p, 720p, 1080p
  • Main-window video recording frame rate presets: 1, 2, 5, 10, 15, 25, 30, 60 fps
  • I/Q analyzer audio recording: WAV, 16-bit, 48 kHz
  • I/Q analyzer I/Q recording: WAV/PCM-style I/Q file, stereo I/Q samples
  • I/Q analyzer video recording: MP4 or GIF; MP4 can include demodulated audio

Default reset values

The RESET PARAMS button restores the main spectrum analyzer to typical defaults:

  • Frequency range: 920 - 960 MHz
  • RBW: 50 kHz
  • Combined gain: 52 dB
  • Frequency shift: 0 MHz
  • Peak trace: enabled
  • Max hold trace: enabled
  • Waterfall: enabled
  • Waterfall palette: start -110 dB, length 65 dB
  • Waterfall speed: 4
  • Video area: SPECTR
  • Video format: GIF
  • Video resolution: 540p
  • Video frame rate: 15 fps
  • STATS interval: SEC