Hey there! This is my take on a terminal monitor for SDR hardware. I wanted something that could hunt down every bit of diagnostic data from your radio and stream it straight to your terminal.

I didn't want to cut corners, so this definitely isn't just a lazy hardware info tool clone. It delivers raw, real-time metrics (spectrum, waterfall, ADC health, gain chain) right inside the terminal. It's lightweight, distraction-free, and fits perfectly into a tmux pane, an SSH session, or the custom screen of your cyberdeck.

It's a one-person project built in my spare time, and honestly, I made it for you ❤️. Use it however you like, beat on it, and don't be shy: open issues, dig through the code, and if you've got a good idea, send it my way as a pull request or just a message. This is an open table, not my private garage.

→ Full user guide - everything below, in depth. Or jump straight to:

It's a terminal app, so brace yourself for the visual spectacle of monospace text in color. The only special effects are honest dBFS numbers.

Screenshots, split by device. More to come. Got a clean capture on your hardware? Drop it in user_docs/pics/ and send a PR (RTL-SDR shots from different tuners especially welcome).

Everything your radio knows about itself, in real time, without leaving the terminal.

• Spectrum analyzer - FFT with EMA smoothing, peak hold, noise floor tracking, dBFS axis, zoom, band-plan overlay, and persistent frequency markers
• Waterfall - scrolling spectrogram in truecolor / 256-color / 16-color, with adjustable color scale, history scroll-back, and frame averaging for longer time windows
• Focus modes - press the highlighted letter in a panel's title to take it over: e spectrum, l waterfall, plus cursor read-outs, holds, and markers without ever touching the mouse

• RF chain - tuned frequency with wavelength (λ, λ/4 for cutting antennas), a visual gain chain, estimated noise figure (Friis), minimum detectable signal (MDS) in dBm, an ADC-utilisation gauge, and a gain advisor that tells you when you're starving or clipping the front end
• IQ diagnostics - DC offset (I/Q + magnitude gauge), DC spike level, amplitude/phase imbalance, and image rejection ratio (IRR), the number that tells you how clean your quadrature really is
• IQ histogram - ADC amplitude distribution with a Low/Mid/Clip breakdown and PAPR (crest factor) that fingerprints the signal type at a glance
• Timing - USB transfer cadence, throughput, and jitter with a quality verdict and session peak tracking
• Hardware vitals - drops, ADC saturation, sdrtop's own CPU/RAM, USB errors, configured-vs-measured sample rate, and buffer fill, every one with a trend sparkline

• Frequency sweep - scan a band wider than one window can show; sdrtop retunes across it, stitches the result into a single curve with band-plan labels, and lets you press Enter on a peak to tune straight to it
• Micro field views - the deliberately tiny mode (0). The idea: sdrtop shouldn't need a full terminal to be useful. When it's squeezed into a slim tmux split, an SSH session on a phone, or the postage-stamp screen of a cyberdeck, the full panels stop being readable, so the micro views strip each concern down to a single glance (signal · gain · health · sweep) and let you cycle between them. One number that matters, big enough to read across the room. (Heads up: the looks are still cooking, the idea's solid, the pixels are a work in progress.)
• Signal strip - one live bar with the essentials: P/NF · channel power · noise floor · ADC saturation · drops · buffer fill · IQ imbalance · RBW
• Observer mode - if another app already holds the radio, sdrtop shows device identity, the owning process, and USB stats instead of falling over, then reclaims the device when it's free

• Six themes - sdr · nord · dracula · gruvbox · catppuccin · solarized
• Layout presets - general + specialised lab layouts; switch on the fly with the number keys, cycle with p, or define your own in the config

Every lab panel marks itself [STALE] the moment RX stops, so a frozen number is never mistaken for a live one. Because the only thing worse than no data is confidently wrong data.

Requirements: Linux · HackRF One or RTL-SDR · libhackrf + librtlsdr + pkg-config · Rust stable

# Arch
sudo pacman -S hackrf rtl-sdr pkgconf rust

sudo apt install libhackrf-dev librtlsdr-dev pkg-config

You also need Rust installed. If you don't have it yet:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

cargo build --release
./target/release/sdrtop

Press Space to start receiving. Press ? for the key reference. Press q to quit and save.

On an RTL-SDR the gain keys adapt to the hardware: ↑/↓ step the tuner's single discrete gain table and a toggles tuner AGC (there's no separate VGA stage, so [/] sit out). The UI relabels itself accordingly, no muscle memory to relearn. With more than one radio plugged in, a picker appears at launch; pin one with --device hackrf|rtlsdr.

Everything is saved automatically to ~/.config/sdrtop/config.toml when you quit, and hand-editing is safe: a missing or broken file just falls back to defaults. Go ahead, mangle it; the parser has seen worse.

[radio]
frequency_hz = 92800000      # tuned center frequency
sample_rate  = 2000000.0     # HackRF 2-20 MHz · RTL-SDR 0.9-3.2 MHz
lna_gain     = 24            # HackRF LNA / RTL-SDR tuner gain
vga_gain     = 30            # HackRF only (ignored on RTL-SDR)
amp_enabled  = false        # HackRF RF amp / RTL-SDR tuner AGC

[display]
active_preset      = "spectrum_waterfall"
waterfall_max_rows = 64

# Spectrum markers persist here, one block each
[[display.spectrum_markers]]
freq_hz = 92800000
label   = "FM Radio"

[sweep]
start_hz = 400000000         # frequency scanner: band start
stop_hz  = 500000000         # band end
dwell_ms = 200               # measure time per step (50-2000)

[theme]
base = "nord"
# optional per-field overrides:
# border_accent = "#88c0d0"
# value_hi      = "#ebcb8b"

Themes: sdr (default) · nord · dracula · gruvbox · catppuccin · solarized. See Themes.

Custom layouts: define your own [presets.*] blocks and they merge with the built-ins, surviving every save. Full reference in Configuration.

Hardware support is added only after physical testing on real devices. No guessing from datasheets. (Translation: the list moves at exactly the speed of my hobby budget.)

The feature set is in. So the whole focus has shifted to making what's already here genuinely good:

• UI polish - layout, spacing, color, readability, and the small edge cases that make a TUI feel hand-built instead of merely functional
• Micro view redesign - the field views (0) do their job, but the layout deserves a rethink: bigger, calmer, easier to read at a glance on a tiny screen
• Sharper radio math - auditing and refining the derived measurements (NF, MDS, IRR, PAPR, sample-rate accuracy, timing) so the numbers are not just present but trustworthy
• Bug fixes - hunting down the rough edges before piling on anything new

No shiny new features until this list feels done. Quality arc, not a feature sprint. ✨

• RTL-SDR support - R820T / R828D / E4000, the most common dongle on Earth, behind a clean device-abstraction layer ✅ in and working. Community-contributed and confirmed on real hardware (RX + observer mode). The RTL clone zoo is vast and I can't test it all, so it still wants testing across the variety, reports welcome and genuinely useful.

• Airspy Mini / Airspy HF+ Discovery
• HackRF Pro
• LimeSDR / bladeRF / SDRplay / PlutoSDR via SoapySDR

• Frequency scanner mode - the lab_sweep / micro_sweep scanner ✅ done
• Signal recording to file
• In-app config editing (no hand-editing TOML)

sdrtop is built to support every SDR device out there, but that requires actually owning them. Development here runs on a HackRF One and a PortaPack H4M. The RTL-SDR backend is now in and working (community-contributed, confirmed on real hardware), the most common SDR hardware in the world, and the most impactful single addition this project could make. I just don't have a dongle here yet, so it's still on the buy list, and testing across the clone zoo is community-powered for now.

The more expensive hardware (Airspy, LimeSDR, SDRplay) I'm saving toward, but that takes longer. If you use sdrtop and want to see support for your device sooner, contributions go directly toward hardware purchases. Every device that arrives gets a proper backend: tested on real hardware, documented, shipped.

No pressure, but if this scratches an itch for you, this is where it goes.

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Credits