Skwad

A frequency coordinator for FPV drone pilots. When multiple pilots fly together, everyone needs to be on a different video channel to avoid interference. Skwad handles the channel math so pilots can scan a QR code, enter their gear info, and get told which channel to use.

How It Works

1. One pilot taps Start Session and gets a 6-character code
2. Everyone else scans the QR code or enters the code
3. Each pilot picks their video system and gear settings
4. Skwad assigns non-conflicting channels based on everyone's actual signal widths
5. If someone joins and there's no clean slot, they choose: buddy up on a shared frequency or partial rebalance to shift one pilot and make room

Sessions update live — any join, leave, or channel change is reflected on everyone's screen within seconds.

Direct Links

Share these for one-tap deep links into the app:

• skwad.atxfpv.org — main app
• skwad.atxfpv.org/s/{CODE} — join a specific session
• skwad.atxfpv.org/feedback — open the feedback form
• skwad.atxfpv.org/translate — flag a bad translation (Translation category pre-selected)

Features

• Smart channel assignment. The optimizer calculates required spacing for each pilot pair based on their actual signal widths and the session's power ceiling. It's not "stay two channels apart" — it's real RF math.
• Mixed system support. Analog, DJI (V1/O3/O4), HDZero, Walksnail, and OpenIPC all in the same session with correct bandwidth-aware spacing.
• Spotter mode. Join a session as an observer without taking a frequency slot. Spotters can lead sessions, manage pilots, and switch to a flying video system when they're ready.
• Session leader controls. Add/remove pilots, force channel changes, rebalance all assignments, adjust power ceiling, transfer leadership.
• QR code join. One tap to share, one scan to join. Works with phone cameras and in-app scanner.
• Conflict detection. Real-time danger/warning indicators when pilots are too close, with IMD (intermodulation distortion) scoring.
• Spectrum visualization. Live view of the 5.8 GHz band showing each pilot's signal width, conflicts, and IMD products.
• Fixed channels (race mode). Leader can lock the session to an optimized 2-5 channel preset for structured events, and switch to a different preset mid-session if the pilot mix changes. Pilots whose equipment can't tune any of the locked channels are refused at join with a clear dialog.
• 14 languages. Auto-detected from browser, switchable in the footer. Most locales are machine-translated and need native-speaker review — tap /translate in any language to flag issues.
• In-app feedback. Report bugs, request features, or suggest translation fixes — direct links at /feedback and /translate. Submissions go straight to GitHub Issues.
• Usage dashboard. Anonymous aggregate stats at /usage — session counts, video system distribution, and a map of where sessions have been hosted.
• Installable PWA. Add to home screen on any device.

Supported Video Systems

System	Bandwidth	Notes
Analog (Race, Fatshark, Boscam E, Low Race)	20 MHz	Pilot selects which bands their VTX supports
HDZero	20 MHz	Race Band frequencies
DJI V1 / Vista	20 MHz	Stock (4ch) or FCC unlocked (8ch)
DJI O3	20 or 40 MHz	Stock (3ch) or FCC unlocked (7ch at 20MHz, 3ch at 40MHz)
DJI O4 / O4 Pro	20, 40, or 60 MHz	Stock/FCC/Race Mode depending on goggles
Walksnail Avatar	20 MHz	Standard or Race Mode
OpenIPC	20 MHz	Single channel (5825 MHz)
Spotter	—	Observer, no frequency assignment

See frequency-reference.md for complete channel tables.

Running It

Docker

docker build -t skwad .
docker run -p 8080:8080 -v skwad-data:/data skwad

From Source

Requires Go 1.24+.

go build -o skwad .
DB_PATH=./skwad.db ./skwad

The server starts on port 8080 by default. Set PORT, DB_PATH, and STATIC_DIR environment variables to override.

API

Method	Endpoint	Description
POST	/api/sessions	Create session
GET	/api/sessions/{code}	Get session state
POST	/api/sessions/{code}/join	Join session
POST	/api/sessions/{code}/preview-join	Preview join (dry-run)
GET	/api/sessions/{code}/poll	Poll for version changes
POST	/api/sessions/{code}/rebalance	Full reoptimize (leader only)
POST	/api/sessions/{code}/preview-rebalance	Preview rebalance (dry-run)
POST	/api/sessions/{code}/transfer-leader	Transfer leadership (leader only)
POST	/api/sessions/{code}/add-pilot	Add pilot (leader only)
PUT	/api/sessions/{code}/fixed-channels	Change fixed channel set mid-session (leader only)
POST	/api/pilots/{id}/preview-channel?session=CODE	Preview channel change (dry-run)
PUT	/api/pilots/{id}/channel?session=CODE	Change channel
PUT	/api/pilots/{id}/video-system?session=CODE	Change video system
PUT	/api/pilots/{id}/callsign?session=CODE	Change callsign
DELETE	/api/pilots/{id}?session=CODE	Remove pilot
POST	/api/feedback	Submit feedback
GET	/api/usage	Aggregate usage stats

Leader-only endpoints check the X-Pilot-ID request header against the session's leader. Sessions expire after 12 hours.

Technical Details

• Backend: Go 1.24, stdlib net/http router, SQLite via modernc.org/sqlite (pure Go, no CGO)
• Frontend: Vanilla HTML/CSS/JS, no build step, installable as PWA
• Database: SQLite with WAL mode
• Real-time: Clients poll every 5 seconds (no WebSocket)

For how the optimizer works (graduated escalation, guard bands, buddy groups, fixed channels), see fpv-optimizer.md.

For channel tables and spacing analysis, see frequency-reference.md and docs/channel-separation-guide.md.

Project Structure

main.go                  # HTTP server and routing
freq/
  tables.go              # Channel tables, guard bands, bandwidth
  optimizer.go           # Frequency assignment and graduated escalation
api/
  handlers.go            # API endpoint handlers
  feedback.go            # Feedback endpoint (GitHub Issues integration)
db/
  db.go                  # SQLite database layer
static/
  index.html             # Single-page app
  app.js                 # Client-side logic
  style.css              # Styles
  sw.js                  # Service worker (network-first caching)
  i18n.js                # Internationalization module
  locales/               # Translation files (14 languages)
  changelog.html         # What's New page
  freq-guide.html        # Interactive frequency guide
  usage.html             # Usage dashboard

Help Translate Skwad — Native Speakers Wanted

Skwad supports 14 languages: English, German, Italian, Bulgarian, Traditional Chinese, Korean, Japanese, French, Spanish, Brazilian Portuguese, Simplified Chinese, Thai, Dutch, and Polish.

Most of these were machine-translated and haven't been verified by a native speaker yet. If you read one of these languages and something reads awkwardly, loses meaning, or just sounds like a robot wrote it, we'd genuinely love your help cleaning it up.

Fastest way to flag something: Switch the app to your language (footer dropdown), notice the issue, then open skwad.atxfpv.org/translate — it opens the feedback form with the Translation category pre-selected. Paste or paraphrase the string and suggest a better rendering. Each submission creates a GitHub issue automatically.

Structured correction or a new language: Open a Translation Request issue.

Code contribution: Submit a PR with an updated static/locales/{lang-code}.json, based on static/locales/en.json. Keep the keys identical — only translate the values.

License

Apache License 2.0. See LICENSE.