SDR Visual Suite

Go-based SDRplay RSP1b live spectrum + waterfall visualizer with a minimal event recorder.

Features

• Live spectrum + waterfall web UI (WebSocket streaming)
• Event timeline view (time vs frequency) with detail drawer
• In-browser spectrogram slice for selected events
• Basic detector with event JSONL output (data/events.jsonl)
• Events API (/api/events?limit=...&since=...)
• Runtime UI controls for center frequency, span, sample rate, tuner bandwidth, FFT size, gain, AGC, DC block, IQ balance, detector threshold
• Display controls: averaging + max-hold
• Optional GPU FFT (cuFFT) with toggle + /api/gpu
• Recorded clips list placeholder (metadata only for now)
• Windows + Linux support
• Mock mode for testing without hardware

Quick Start (Mock)

# From repo root

go run ./cmd/sdrd --mock

Open http://localhost:8080.

SDRplay Build/Run (Real Device)

This project uses the SDRplay API via cgo (sdrplay_api.h). Ensure the SDRplay API is installed.

Windows

$env:CGO_CFLAGS='-IC:\Program Files\SDRplay\API\inc'
$env:CGO_LDFLAGS='-LC:\Program Files\SDRplay\API\x64 -lsdrplay_api'

go build -tags sdrplay ./cmd/sdrd
.\sdrd.exe -config config.yaml

Windows (GPU FFT / cuFFT)

Requires the NVIDIA CUDA Toolkit installed (cuFFT + cudart). Ensure CUDA bin and lib/x64 are on PATH/LIB.

$env:CGO_CFLAGS='-IC:\Program Files\SDRplay\API\inc -IC:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v12.4\include'
$env:CGO_LDFLAGS='-LC:\Program Files\SDRplay\API\x64 -lsdrplay_api -LC:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v12.4\lib\x64 -lcufft -lcudart'

go build -tags "sdrplay,cufft" ./cmd/sdrd
.\sdrd.exe -config config.yaml

Linux

export CGO_CFLAGS='-I/opt/sdrplay_api/include'
export CGO_LDFLAGS='-L/opt/sdrplay_api/lib -lsdrplay_api'

go build -tags sdrplay ./cmd/sdrd
./cmd/sdrd/sdrd -config config.yaml

Configuration

Edit config.yaml:

• bands: list of band ranges
• center_hz: center frequency
• sample_rate: sample rate
• fft_size: FFT size
• gain_db: device gain (gain reduction)
• tuner_bw_khz: tuner bandwidth (200/300/600/1536/5000/6000/7000/8000)
• use_gpu_fft: enable GPU FFT (requires CUDA + cufft build tag)
• agc: enable automatic gain control
• dc_block: enable DC blocking filter
• iq_balance: enable basic IQ imbalance correction
• detector.threshold_db: power threshold in dB
• detector.min_duration_ms, detector.hold_ms: debounce/merge

Web UI

The UI is served from web/ and connects to /ws for spectrum frames.

Controls Panel

Use the right-side controls to adjust center frequency, span (zoom), sample rate, tuner bandwidth, FFT size, gain, AGC, DC block, IQ balance, and detector threshold. Preset buttons provide quick jumps to 40m/20m/17m.

Event Timeline

• The timeline panel displays recent events (time vs frequency).
• Click any event block to open the detail drawer with event stats and a mini spectrogram slice from the latest frame.

Config API

• GET /api/config: returns the current runtime configuration.
• POST /api/config: updates center_hz, sample_rate, fft_size, gain_db, tuner_bw_khz, use_gpu_fft, and detector.threshold_db at runtime.
• POST /api/sdr/settings: updates agc, dc_block, and iq_balance at runtime.
• GET /api/gpu: reports GPU FFT availability/active status.

Events API

/api/events reads from the JSONL event log and returns the most recent events:

• limit (optional): max number of events (default 200, max 2000)
• since (optional): Unix milliseconds or RFC3339 timestamp

Example:

curl "http://localhost:8080/api/events?limit=100&since=1700000000000"

Tests

go test ./...

Troubleshooting

• If you see sdrplay support not built, rebuild with -tags sdrplay.
• If the SDRplay library is not found, ensure CGO_CFLAGS and CGO_LDFLAGS point to the API headers and library.
• Use --mock to run without hardware.