Inputs & outputs — xng docs

Radios and files go in; Airframes, JSON, live maps, metrics, and a dozen wire formats come out. Because every mode shares one message model, the same output flags work for all of them.

Inputs

xng presents a single sample-source interface over several backends. You pick one with --sdr "driver=…" (or sdr = in a station file).

Source	Driver	Notes
RTL-SDR	`driver=rtlsdr`	The budget workhorse for VHF (ACARS/VDL2/AIS); with an L-band antenna + LNA, also Aero/STD-C/Iridium/ADS-B.
Airspy R2 / Mini	`driver=airspy`	Native libairspy backend (`--features airspy`). 24 MHz–1.75 GHz. `serial=` selects a unit, `bias=1` powers an LNA.
Airspy HF+ / Discovery	`driver=airspyhf`	Native libairspyhf (`--features airspyhf`). The classic HFDL receiver.
SDRplay RSP	`driver=sdrplay`	Via SoapySDR.
HackRF, LimeSDR, USRP, BladeRF…	SoapySDR module	Anything with a SoapySDR driver works.
IQ files	`xng decode <file>`	`cf32` / `cs16` / `cs8` / `cu8`, guessed from the extension. No hardware needed.
External decoders	`xng extern`	Wrap `dumphfdl` / `dumpvdl2` / `acarsdec` output onto the xng bus.

--gain is always in dB; omit it for hardware AGC. With a native backend compiled in, the driver name auto-routes to it — add backend=soapy to force the SoapySDR path instead.

Hardware & antennas by band

VHF — ACARS, VDL2, AIS

Any RTL-SDR and a vertical antenna. The easy place to start.

HF — HFDL

An HF-capable SDR (Airspy HF+ / Discovery, SDRplay) and an HF antenna.

L-band — Aero, STD-C, Iridium

A patch/L-band antenna with an LNA. Iridium does best on an Airspy R2 sampling wide.

1090 MHz — ADS-B

A passive 1090 antenna. --receiver-pos lat,lon unlocks surface positions.

Outputs

Every flag below can be combined; a single decode can fan out to all of them at once.

Flag	Destination
(default)	Human-readable console one-liners
`--json` / `--jsonl <file>`	Raw JSON to stdout / one normalized message per line to a file
`--udp host:5550`	acarsdec-compatible JSON datagrams (repeatable)
`--feed-airframes --station-id <id>`	Feed to `feed.airframes.io`
`--metrics 0.0.0.0:9090`	Prometheus metrics
`--sbs 0.0.0.0:30003`	SBS / BaseStation TCP (Mode S + UAT/HFDL positions)
`--beast 0.0.0.0:30005`	Beast binary TCP (carries the 12 MHz MLAT clock)
`--nmea-tcp` / `--nmea-udp`	NMEA AIVDM server / push (AIS)
`--mqtt mqtt://…`	JSON to `<prefix>/<mode>` on an MQTT broker
`--asf2-grpc` / `--asf2-quic`	asf-2.0 multiplexed feeding over gRPC / QUIC
`--gsmtap [addr]`	Iridium GSM frames to Wireshark via GSMTAP
`--http 0.0.0.0:8080`	Live web dashboard + data API + geo export

The --beast and --sbs streams are exactly what community ADS-B networks consume, so xng can feed them alongside Airframes. Point a Beast feeder at Airplanes.Live or Plane.Watch, and run --http for your own tar1090 map at the same time.

The web dashboard

--http serves a dark, live map and a tabbed entity table — aircraft (Mode S / UAT / HFDL / ACARS merged by ICAO), ships (AIS), beacons, trains, pagers, and satellites — plus a streaming message panel with per-mode filter chips, position trails, and Iridium beam overlays.

bash

xng listen --sdr driver=rtlsdr --mode adsb --channels 1090 \
    --receiver-pos 47.62,-122.35 --http 0.0.0.0:8080
# then open http://localhost:8080

It also exposes drop-in data APIs and exports:

/data/aircraft.json

tar1090 / graphs1090 / VRS compatible — point those tools straight at it.

/data/export.geojson · .gpx · .kml

RFC 7946 GeoJSON, GPX 1.1, and OGC KML 2.2 exports.

/api/state

Cross-mode distress surface — ADS-B 7500/7600/7700, AIS SART/MOB/EPIRB, STD-C/DSC distress, SARSAT 406.

asf-2.0: one connection, every channel

Airframes Standard Format v2 is xng’s multiplexed feeding protocol. A single protobufEnvelope schema carries every channel, SDR, and mode over one gRPC or QUIC connection — with reconnect and backpressure handling, nanosecond timestamps, signal-quality metadata, and the raw payload always preserved for server-side re-decode.

bash

# feed a remote ingest server over gRPC
xng listen --sdr driver=rtlsdr --mode acars --asf2-grpc http://ingest:6001

# run the reference ingest server
xng ingest --grpc 0.0.0.0:6001 --quic 0.0.0.0:6011

See Architecture for how the pipeline produces these envelopes.