OnAir 3.6

OnAir 3.6 adds 20 modes (178 in all), measures and improves how well the decoders hear weak signals, and makes the app easier to start with. Everything below is merged and tested; the last section says plainly what was only tested on synthetic signals.

Measured numbers come from OnAir's own test signals, not from over-the-air recordings, unless a line says so.

New modes

• GK-2A LRIT (family 230) and HRIT (231), with DES-ECB and a bundled JPEG 2000 decoder (OpenJPEG 2.5.3) for the pictures.
• FengYun: three mode entries, FY-4 LRIT with satellite choice (232), FY-4A HRIT (233) and FY-2 S-VISSR (234); FY-3 AHRPT (235) and FY-3 MPT (236).
• PACTOR-II, PACTOR-III, PACTOR-IV (physical layer) and Multitone framing.
• SITOR-B receiver with the M.476 table, replacing the earlier placeholder row.
• SELCAL as its own mode with a call log; CCIR / ZVEI / EEA / EIA / DZVEI selective calls next to POCSAG and FLEX in the pager modes.
• Inmarsat Aero C voice in the Voice tab (aeroambe codec plug-in, installed by you); Iridium voice finished.
• MFSK gets MFSK128, MFSK64L and MFSK128L, and picture reception as in fldigi (grey and colour, X1/X2/X4) with a live picture, Save PNG and thumbnails in the MFSK window.
• Smart CubeSat: one "Auto decode cubesats" button that scans a wide capture, tells FSK, AFSK, BPSK (including AO-40) and CW carriers apart and decodes them, with a next-passes list, packet log, FUNcube telemetry and exports (SatNOGS JSON, CSV, KISS). Satellite table from SatNOGS DB.
• Modes that were labelled work in progress are finished and lose the label: eLoran, DME, DGPS beacons, Yaesu Fusion, MPT1327, EDACS, LTR.

Decoder quality and sensitivity

• Sensitivity measured against theory in three passes, with harness modes for HFDL, NAVTEX, DSC VHF, CDR, DVB-C, ATSC 3.0, DRM 16-QAM, DRM+, airband and cell; tables are in the docs per mode.
• ATSC 3.0: channel estimate from the pilot comb with noise taps dropped (AWGN 4 to 2 dB, TU6 16 to 12 dB).
• DVB-S2: fix for a false header lock at very low Es/N0; VL-SNR hunt first on weak two-header chains.
• Digital voice: frequency capture for narrow-band voice modes and "why is it not decoding" hints; P25 fine capture only beyond 3.6 kHz.
• HFDL: why-bad counters in the Receiver tab. ACARS timing loop 1 dB better.
• eLoran tuning-error tolerance to +-250 Hz; DGPS parity and full RTCM messages; MPT1327 per the 1997 standard with single-bit repair; EDACS real BCH; LTR check bits verified.
• DRM: xHE-AAC config extension elements fixed.
• Auto gain rebuilt: index-table radios, ADC-limited start, SDRplay split, per-mode targets, spur notch.

Ease of use

• Simple / Advanced view per mode, rolled out to ADS-B, AIS, ACARS, VDL2, pagers, APRS, LoRa, TETRA, P25, NXDN, D-STAR, dPMR, M17, radiosondes, Inmarsat-C and Aero, Iridium, Orbcomm and the weather-satellite modes.
• Scan and Identify: one button in the Simple view.
• First-run setup v3 with regional presets, antenna hints, a codec screen and an easy mode.
• Recordings folder: choose where recordings are saved in Settings > Files (default unchanged), and an Open recordings folder button in Iridium, TETRAPOL, trunking, marine VHF, fast scan, DAB, audio and the general receiver.
• Country file (cty.dat, wl_cty.dat) in the Ham view: load a file or download it on a click, and the country, CQ and ITU zone appear after each decoded message.
• Turkish interface language (machine translated, marked as such).
• Spectrum zoom keeps the marker; target mode keeps the marker centred; double click tunes.
• Discord button in the menu bar and the Help menu.
• WEFAX picture rotation; Linux AppImage release asset with in-place update; the Linux .deb is downloaded, checked and the install command shown.

Wide capture, trunking and voice watch

• Everything in view: several signals decoded from one wide capture, with TETRA and Inmarsat span decoders.
• Multi-radio trunking: a pool controller, channel plan and access CSV, per-call recorder, grant taps for P25, DMR, TETRA, MPT 1327, EDACS and LTR, and a trunking window.
• Voice watch list across modes and pager keyword alerts.

Web, relay and AI

• OnAir Web redesigned as a port of the app look, with a settings panel, translations, offline map, AGC / gain and a memory overlay.
• Share my radio: outbound relay client, listener list with kick and block, invites, bans, and the relay service itself (relay/relay.js, one dependency-free Node file).
• Map: icon sprite, grouped layers, filters, themes, shortcuts; ham contacts no longer reach the map as zero.
• MCP server and an AI assistant panel: assistants can drive OnAir through MCP (stdio and HTTP).

Recording, replay and export

• Record and replay for any mode (16-bit recording, SigMF ci16); audit in docs/RECORD-REPLAY.md.
• Shared export bar (CSV, KML, GeoJSON, copy) for more modes; search results as CSV (audit in docs/EXPORT-AUDIT.md).

Bandwidth and sample rate

• Custom bandwidth and sample rate in every mode through one shared path; the default is unchanged and limits only warn (audit in docs/BANDWIDTH-AUDIT.md).

SDK

• Plug-ins and scripts page in Settings; plug-in SDK audit in docs/PLUGIN-SDK.md.
• Mesh transmit from the user's own node identity.

DSC and SELCAL

• DSC radio-level and bit-level robustness sweeps (offsets, mistuning, noise, fading, 250 ksps to 20 Msps, clock error, clipping).
• SELCAL mode, see above.

Fixes and pull requests

• #409, #410, #418: H.264 hardware-decode fallback, general-receiver wheel tune, FM scan hop timeout; issues #408, #411, #412 handled.
• Pager keyword patterns with nested quantifiers are refused (they hung the regex engine).
• Pull requests: the app's mute now also silences the audio monitor (#434, bellx2); plug-ins can play sound through audio_out (#433, bellx2); Turkish catalog (#428, ptmy53); Inmarsat satellite naming, shared thread pool and carrier width 10 dB under peak (#413, #415, #416, BrunoKlu); HydraSDR RFOne driver (#417); Aero voice parts of #414.
• Windows / test carry-over failures from 3.5 fixed; web policy classes SITOR and PACTOR as blocked.

CI

• Timing tests made deterministic; MinGW near macro build fix; a real-signal test library (ADS-B, DTMB, DSC; docs/REAL-SIGNALS.md); MCP protocol tests; 15 more web client JS tests.

Known limits

• Most new decoders were tested on synthetic signals made by OnAir's own generators, not over the air. That includes Smart CubeSat (only one real FUNcube frame was decoded), the MFSK pictures, the GK-2A and FengYun modes, trunking and voice watch.
• MFSK on real Shortwave Radiogram recordings does not decode yet: three public recordings gave no text or picture, although the synthetic tests pass. Reports with a short recording are welcome.
• Smart CubeSat: FSK has no frequency tracking (a carrier more than about 1.5 kHz off is lost); LoRa satellites and CCSDS convolutional framing are not included.
• Screens added late in the cycle (Smart CubeSat, MFSK pictures, Settings > Files, Country file) were compiled and tested in code but are new to real users.
• Wide capture decoding several signals is proven for about 10 modes; other modes still decode one signal per capture.
• Machine-translated strings are listed in app/i18n/unreviewed.
• Two timing-sensitive tests failed once each in earlier CI runs of this code and passed in others: custom_bandwidth_all (ATSC 3.0 engine start on a slow Linux runner) and multitv_wide (a crash on Windows). The last full CI run on the release code was green on Linux, macOS and Windows. If you see either one, please report it.

Build notes

• macOS, Linux and Android files were built by GitHub from commit 582d283. The Windows files were cross-built on the maintainer's Mac from the same commit with one extra line guarded for MinGW (core/src/engine/updater.cpp), which is commit 2503421, the one this release is tagged at. That line only exists in the Linux AppImage branch, so the other platforms are identical.
• The Windows files have not been opened on a Windows machine by the maintainer yet.