Longpath

A cross-platform SDR console for OpenHPSDR radios

Lineage and licence

Longpath is a fork of NereusSDR © J.J. Boyd (KG4VCF), which is itself a C++20 / Qt6 port of Thetis © FlexRadio Systems, Doug Wigley (W5WC), Richard Samphire (MW0LGE) and the OpenHPSDR contributors. Architecture and substantial code come from AetherSDR © Jeremy (KK7GWY). The DSP engine is WDSP © Warren Pratt (NR0V) / TAPR, descending from DttSP by Frank Brickle (AB2KT) and Bob McGwier (N4HY). Further upstreams: freedv-gui, radae_nopy (BSD-2-Clause), r8brain-free-src (MIT), and the Anvelina PRO III gateware (GPLv3).

Every copyright notice, licence header and author tag from those projects is preserved verbatim in this tree. Nothing was removed when the fork was renamed. The full record lives in docs/attribution/ — THETIS-PROVENANCE.md, AETHERSDR-PORTS.md, FREEDV-GUI-PROVENANCE.md, ASSETS.md.

Longpath is licensed under the GNU General Public License, as its upstreams require. See LICENSE.

Fork maintained by Martin Fischer, OE5SOS.

Important

📖 Alpha testers, start here: docs/debugging/v0.5.2-alpha-tester-smoketest.md

v0.5.2 sits on top of v0.5.1 (patch) and v0.5.0 (substantial minor). One major epic + a new SKU + a UI subsystem + a polish tail land together:

1. Phase 3P-II: External RF accessories (PGXL + TGXL) + analog S-Meter port. AetherSDR 1:1 baseline for 4O3A Power Genius XL amplifier telemetry and Tuner Genius XL antenna tuner control over Ethernet (TCP 9008 / 9010), plus the Thetis analog S-Meter widget on the operator banner with four RX modes (Signal / Sig Avg RXA_S_AV / Signal Peak / Max Bin). New Setup pages under Setup → Network (Peripherals + PGXL Advanced + TGXL Advanced) and Setup → Transmit (PGXL Interlock). Fault log, tune memory, connection diagnostics, optional TX interlock policy (Disabled / Warn / Block + SWR gate + grace).
2. ANAN-G2E (HermesC10) SKU port. New board enum and capability row, hardware profile init verified against Thetis v2.10.3.15, codec wrappers (SetADCSupply + LRAudioSwap), discovery byte 0x14 mapping, BPF1 algorithm family, PA telemetry, per-model preamp items, EXT label overrides, P2 RX unblock + crash fix.
3. Applet visibility controller. Hamburger menu embedded in the AppletPanel banner, View → Containers → Applets show/hide section, two-way menu sync, capability-gated availability axis, RADE-aware routing, master-toggle live UI gating, persistence across launches. View → Network Applets retired.
4. Polish tail. 4O3A integration cleanup (PGXL/TGXL handshake + route-aware FLEX discovery + master-toggle gating), TCI live-state fixes + 5 review issues, PS-A persistence, PA profile and quit handling, G2E P2 RX unblock + crash fix.

Existing users: no action required. Saved radios, mic profiles, DSP settings, container layout, spectrum/waterfall settings, PA cal points, per-band tune power, spot-system identity all carry forward. No SettingsSchemaVersion bump in v0.5.x (the last bump was v5 in v0.4.0).

Returning testers: the v0.5.0 epic mix (Phase 3J-1 TCI v2.0 WebSocket server, Phase 3J-2 spot system + FreeDV Reporter + PSK Reporter, Phase 3R RADE as a peer mode RX + TX) is unchanged. The v0.4.0 doc at docs/debugging/v0.4.0-alpha-tester-smoketest.md remains the authoritative walkthrough for PureSignal, the Display + DSP-Options refactor, anti-VOX, live-apply sample rate, and the AF Gain + VAX calibration fix. Earlier walkthroughs at docs/debugging/v0.3.2-alpha-tester-smoketest.md and docs/debugging/v0.3.1-alpha-tester-smoketest.md remain available for historical reference.

J.J. Boyd ~ KG4VCF

Longpath is a C++20/Qt6 port of Thetis — the canonical OpenHPSDR / Apache Labs SDR console, itself descended from FlexRadio PowerSDR — carrying its radio logic, DSP integration, and feature set forward to a native cross-platform codebase (macOS, Linux, Windows) with a Qt-based GUI. The Thetis contributor lineage (FlexRadio Systems, Doug Wigley W5WC, Richard Samphire MW0LGE, and the wider OpenHPSDR community) is preserved per-file in source headers and summarized in docs/attribution/THETIS-PROVENANCE.md. Distributed under GPLv3 (root LICENSE), elected under the "or later" grant in upstream Thetis source-file headers (Thetis is GPLv2-or-later). A verbatim copy of GPLv2 ships at docs/attribution/LICENSE-GPLv2 for reference, since several WDSP and ChannelMaster source files explicitly reference v2.

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Supported Radios

Works with any radio implementing OpenHPSDR Protocol 1 or Protocol 2:

• Apache Labs ANAN line — ANAN-G2 (Saturn), ANAN-7000DLE, ANAN-8000DLE, ANAN-200D, ANAN-100D, ANAN-100, ANAN-10E
• Hermes Lite 2
• All OpenHPSDR Protocol 1 radios — Metis, Hermes, Angelia, Orion, Orion MkII
• All OpenHPSDR Protocol 2 radios

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Releases & Installation

Pre-built binaries for Linux (AppImage, x86_64 + aarch64), macOS (DMG + PKG, Apple Silicon + Intel), and Windows (NSIS installer + portable ZIP, x64) are published as GitHub Releases:

https://github.com/OE5SOS/Longpath/releases

All artifacts are GPG-signed (KG4VCF) via SHA256SUMS.txt.asc. To verify:

gpg --keyserver keyserver.ubuntu.com --recv-keys KG4VCF
gpg --verify SHA256SUMS.txt.asc SHA256SUMS.txt
sha256sum -c SHA256SUMS.txt

Alpha builds: until Apple Developer ID and Authenticode certificates are obtained, macOS users will need to right-click → Open the DMG on first launch, and Windows users will see a SmartScreen warning to click through. Linux is unaffected. See the per-release notes for details.

v0.4.0 status: macOS DMG and PKG remain Apple Developer ID-signed and notarized; Gatekeeper accepts them on first launch. Windows installer remains unsigned (Authenticode certificate pending); SmartScreen "More info → Run anyway" still applies.

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Current Status

Current release: v0.5.2 (2026-05-24). Substantial release on top of v0.5.1 (and v0.5.0 underneath). One major epic plus a new SKU port, a new UI subsystem, and a polish tail: Phase 3P-II External RF accessories (AetherSDR 1:1 PGXL + TGXL baseline, Thetis analog S-Meter port with 4 RX modes, connection robustness with exponential auto-reconnect / keepalive / RTT-correlated ping / full PGXL pairing flow, advanced UI with Fault Log / Tune Memory / TX Interlock Policy / power-cap toast); ANAN-G2E (HermesC10) SKU port (new board enum, hardware profile verified against Thetis v2.10.3.15, codec wrappers, BPF1 algorithm, PA telemetry, P2 RX unblock + crash fix); Applet visibility controller (hamburger menu on AppletPanel banner, View → Containers → Applets show/hide, capability-gated availability, persistence); polish tail (4O3A integration cleanup, TCI live-state fixes + 5 review issues, PS-A persistence, PA profile / quit handling). v0.5.2's 3P-II bench-verification matrix (36 rows) is pending live PGXL + TGXL hardware; the ANAN-G2E matrix (12 rows) is pending live G2E hardware. v0.5.1 (2026-05-15) was the patch before: three ship-blocking release-artifact fixes (Windows rade.dll, macOS x86_64 Qt6::WebSockets, HL2 + Win11 waterfall slider persistence), three correctness fixes (orphan .bak recovery, connect-state-stuck-green, VOX prime-on-connect), and two CodeQL pipeline maintenance fixes. v0.5.0 detail below.

Phase 3J-1: TCI v2.0 WebSocket server. External programs (WSJT-X, JTDX, FreeDV, Quisk, ESDR3, N1MM, Log4OM, contest software) can now drive Longpath over Thetis-compatible TCI. Setup > CAT/Network > TCI Server configures bind interface, port, and sensor intervals; Tools > TCI Server opens the log viewer; the bottom-bar TCI indicator shows live state. The audio pipeline negotiates 8 / 12 / 16 / 44.1 / 48 kHz with per-stream resampling, so FreeDV 8 kHz, Quisk, and JTDX 12 kHz all work end-to-end. 15 closeout items shipped after the initial port stabilized the on-bench behaviour against real clients.

Phase 3J-2: Spot system, FreeDV Reporter, PSK Reporter. Seven spot-source clients in one place: DX cluster, RBN, WSJT-X UDP, SpotCollector / DXLab UDP, POTA HTTPS, FreeDV Reporter Socket.IO, PSK Reporter IPFIX. Tools > Spot Hub (Ctrl+Shift+S) opens a 10-tab modeless dialog; Tools > FreeDV Reporter (Ctrl+Shift+R) opens the 14-column live station view with TX/RX highlights, QSY support, and 2-hour idle auto-removal. Spots render on the panadapter with collision-avoidance stacking and click-to-tune, coloured by a DXCC 4-tier resolver against cty.dat plus the operator's ADIF log.

Phase 3R: RADE as a true peer mode (RX + TX end-to-end). RADE is wired as a first-class DSP mode (DSPMode::RADE_U / DSPMode::RADE_L) and not as a DIGU pretense, a virtual audio bus, or a slice-mute hack. RX decodes through a dedicated RadeChannel; the VFO flag gains a mode-aware SNR row and shows the EOO-decoded speaker callsign when known. TX is end-to-end: TxWorkerThread feeds the RADE encoder and sendTxIq carries the 24 kHz stereo modem output. RadeApplet docks in the right column when RADE is the active mode. Vendored radae_nopy (BSD-2-Clause) plus Opus with LPCNet/FARGAN add about 9 MB to the binary on every platform; neural-net weights are compiled into librade, so no external model file ships.

Bench-fix tail. Wire / parser / UX gaps that surfaced when 3J-1 + 3J-2 + 3R drafts hit real radios, real DX clusters, real WSJT-X feeds, and real WSJT-X TCI cycles. Highlights: first-MOX audio-volume seed, ten missing spot-client lifecycle wires, the DXSpider parser, FreeDV Reporter row-highlight / Socket.IO ACK push / VFO freq-publish throttle, the RADE callsign / idle-clear timer, and cross-source spot dedup via SpotModel::dedupIndexFor.

Earlier releases. v0.4.0 (2026-05-08) shipped a substantial minor release on top of v0.3.2 with five pieces of work landing together: 3M-4 PureSignal (the big new feature: feedback DDC plumbing on Protocol 1 and Protocol 2, calcc.c + iqc.c vendored verbatim from Thetis, PsForm dialog at Tools → PureSignal, AmpView modeless dialog, two-tone IMD overlay on the spectrum, bottom-banner FB+PS indicator pair, enabled on every supported P1 and P2 SKU including HL2 and plain Hermes), a Display + DSP-Options refactor (WDSP avenger() and detector() ports, new Setup → DSP page with 18 controls and RX/TX combo split, in-place filter resize, Filter Impulse Cache, Thetis-faithful FFT slider with 7 windows, NF-aware grid, SpectrumPeaksPage, Multimeter page, SettingsSchemaVersion v5 migration), 3M-3a-iv anti-VOX cancellation feed (closes the v0.3.2 gap so the Anti-VOX gain control actually works; full grpAntiVOX trio on Setup → Transmit → DEXP/VOX), live-apply sample rate (no disconnect needed; 12-step Thetis-faithful coordinator routes through WDSP's SetXcmInrate path; HL2 P1 384 kHz parity), and the AF Gain rewire (KM4BLG) + VAX bus calibration (AF slider through SetRXAPanelGain1 closes a long-standing distortion bug; VAX tap inverse-scales by 1 / afGain so digital-mode apps stay calibrated). v0.3.2 (2026-05-05) shipped DEXP/VOX speech processing end-to-end for the first time, the HL2 mi0bot RF/Tune slider maturity push, full Setup → PA parity + the PA over-drive safety hotfix for high-gain finals (notably the ANAN-8000DLE), and a long tail of persistence and stability fixes. v0.3.1 (2026-05-03) carried forward everything 0.3.0 was supposed to deliver plus per-profile TX bandwidth control, the user-editable filter preset store, TX filter overlay on the panadapter and waterfall, the per-board PA forward-power calibration system, and the Setup IA reshape. HL2 SSB transmit is bench-cleared since v0.3.1's ATT/filter safety audit. Earlier-shipped 3G RX-Epic, 3P-A…I antenna integration, 3O VAX + Linux PipeWire, and the v0.2.x maintenance fixes still apply. 3M-2 CW TX is next up; 3F multi-panadapter, 3H skins, 3K CAT remain not-started.

What's working end-to-end today

• Radio connection — every OpenHPSDR P1 and P2 board. ANAN-G2 (Saturn / Protocol 2), ANAN-10/10E/100/100B/100D/200D, Hermes, Hermes Lite 2, Angelia, Orion, Metis, Red Pitaya — all discover, connect, stream I/Q, demodulate through WDSP, and persist per-radio settings keyed by MAC. BoardCapabilities registry drives per-board DDC count, ADC count, BPF, Alex filter, and sample-rate support; HardwareProfile engine overlays Thetis clsHardwareSpecific.cs behaviour for ambiguous discovery bytes (user-selectable radio-model override in ConnectionPanel).
• Sample-rate wiring — P1 48 / 96 / 192 kHz (+ 384 on Red Pitaya); P2 48 / 96 / 192 / 384 / 768 / 1536 kHz. Per-MAC persistence under hardware/<mac>/radioInfo/. Inline reconnect banner on RadioInfoTab when the selected rate differs from the active wire rate.
• Full Display parity — Setup → Display (Spectrum / Waterfall / Grid & Scales) is wired end-to-end to the renderer on both the QPainter fallback and the QRhi/Metal/Vulkan/D3D12 GPU path. 47-control verification matrix at docs/architecture/phase3g8-verification/README.md. Per-band grid state persists across all 14 bands (160m–6m + GEN + WWV + XVTR) via the first-class Band enum on PanadapterModel.
• Clarity adaptive display — Clarity Blue waterfall palette, ClarityController with cadence / EWMA / deadband, NoiseFloorEstimator percentile, Reset-to-Smooth-Defaults button, Re-tune button + Clarity status badge in the spectrum overlay panel, per-band Clarity memory. Zoom persistence across restarts.
• Full RX DSP parity — 10 WDSP feature slices wired end-to-end through SliceModel → RadioModel → RxChannel → WDSP: AGC advanced (threshold / hang / slope / attack / decay), EMNR (NR2), SNB, APF (SPCW), 3-variant squelch (SSB / AM / FM), mute / audio pan / binaural, NB2 advanced, RIT / XIT client offset, frequency lock, mode containers (FM OPT / DIG / RTTY). Per-slice-per-band persistence under Slice<N>/Band<key>/*.
• VfoWidget rewrite — 4-tab layout (Audio / DSP / Mode / X-RIT), 4×2 DSP toggle grid, AGC 5-button row, S-meter level bar with dBm readout and cyan→green gradient, mode containers, tooltip coverage test. AGC-T ↔ RF Gain bidirectional sync prevents audio-breaking gain runaway.
• Auto AGC-T — NoiseFloorTracker feeds the Auto-threshold timer with MOX guard and agcCalOffset; AUTO button toggles auto-mode; right-click the AGC-T slider opens Setup directly on the AGC/ALC page.
• Step attenuator + ADC overload — StepAttenuatorController with Classic + Adaptive auto-attenuation modes, hysteresis, per-MAC persistence. P1/P2 adcOverflow signal from frame parsers, OVL status badge in RxApplet, per-model preamp items from Thetis SetComboPreampForHPSDR.
• Container / meter system — GPU-rendered meter engine (QRhi 3-pipeline), 31 MeterItem types, 38+ ItemGroup presets (S-Meter, Power/SWR, ALC, ANANMM 7-needle, CrossNeedle, Magic Eye, History, SignalText, TX bar meters), full Thetis-parity Container Settings Dialog (3-column layout, per-item property editors), MMIO external-data subsystem (UDP / TCP-listen / TCP-client / Serial transports; JSON / XML / RAW formats).
• VAX audio routing — Longpath-native multi-channel audio bus. IAudioBus abstraction with 5 platform backends (CoreAudio HAL plugin on macOS, PulseAudio pipes / pactl on Linux, PortAudio on Windows). First-run VAX dialog auto-detects Windows virtual-cable families (VB-Audio / VAC / Voicemeeter / Dante / FlexRadio DAX); MasterOutputWidget in the menu bar; Setup → Audio sub-tabs (Devices / VAX / TCI / Advanced); per-slice VAX channel assignment on the VFO Flag, persisted under Slice<N>/.
• SSB voice transmit on every supported board, including Hermes Lite 2 — TxChannel, mic input pipeline (Pc / Radio / Composite sources), MOX state machine, I/Q output on Protocol 1 and Protocol 2. TX speech processing chain: 10-band parametric TX EQ, TX Leveler, TX ALC (3M-3a-i); CFC multi-band compressor, CPDR companding/drive ratio, CESSB controlled-envelope SSB, Phase Rotator (3M-3a-ii). Per-profile TX bandwidth (FilterLow/FilterHigh on every mic profile, TxApplet TX BW spinboxes, debounced WDSP path). 21 factory mic profiles ported verbatim from Thetis; profile manager with Save / Save-As / Delete; two-tone IMD test mode; VOX / DEXP / Anti-VOX. The HL2 ATT/filter safety audit closed in v0.3.1.
• Connection workflow (Phase 3Q) — single state-machine-driven Disconnected → Probing → Connecting → Connected → (LinkLost | Disconnected). Unicast probe reaches radios across Layer-3 VPN tunnels (WireGuard / ZeroTier / Tailscale). 16-SKU model picker organized by silicon family in the Add Radio dialog. Auto-connect-on-launch with per-radio toggle. Spectrum disconnect overlay (fade + click-to-recover) replaces the v0.2.x "frozen spectrum" mystery state.
• Status-bar chrome — title-bar ConnectionSegment shows [state dot] [▲ tx Mbps] [RTT ms] [▼ rx Mbps] [♪ audio] with hover tooltip and right-click menu. Receive-info BadgePair ladder drops in priority order on narrow windows (mode + filter never drop). StationBlock clickable radio-name anchor. AdcOverloadBadge (yellow > 0, red > 3, 2 s auto-hide). CPU System / App right-click toggle. SVG icon system on StatusBadge. Min-filtered RTT for accurate sub-millisecond LAN ping readout.
• Hermes Lite 2 configuration surface — new Hermes Lite Options tab (I2C control, I/O pin state), N2ADR HERCULES toggle writing all 13 SWL pin-7 entries, signed −28..+32 dB step-attenuator range, 13 SWL bands × 7 pins matrix, full per-MAC persistence. Bigger gaps elsewhere in the app remain; this expands a previously-thin HL2 surface.
• App polish — Help → About Longpath (version / Qt / WDSP / GPG fingerprint / heritage credits), 💡 AI-assisted issue reporter in the menu bar corner (structured prompts, submits to the bug_report.yml / feature_request.yml GitHub templates), radio-model override persistence, P1 full 17-bank C&C round-robin, NetworkDiagnosticsDialog 4-section health grid.
• Packaging — release.yml prepare → build×3 → sign-and-publish pipeline. macOS DMG and PKG are now Apple Developer ID-signed and notarized in v0.3.0+; Windows installer remains unsigned (Authenticode certificate pending). All artifacts GPG-signed via SHA256SUMS.txt.asc. Per-platform artifacts: Linux AppImage (x86_64 + aarch64), macOS DMG + PKG (Apple Silicon + Intel), Windows portable ZIP + NSIS installer.

Deferred / not yet implemented

• TX pipeline 3M-1 (Basic SSB TX) + 3M-3a-i / 3M-3a-ii (TX Processing — EQ / Leveler / ALC / CFC / CPDR / CESSB / Phase Rotator) — shipped in v0.3.0.
• TX pipeline 3M-3a-iii (DEXP/VOX + AMSQ) — shipped in v0.3.2.
• TX pipeline 3M-3a-iv (Anti-VOX cancellation feed) — shipped in v0.4.0.
• TX pipeline 3M-4 (PureSignal) — shipped in v0.4.0. Feedback DDC, calcc.c / iqc.c engine vendored verbatim from Thetis, PsForm, AmpView, two-tone IMD overlay; enabled across the ANAN family + HL2 + plain Hermes.
• TX pipeline 3M-2 (CW TX) — sidetone, firmware keyer, QSK / break-in. Next major epic.
• TX pipeline 3M-3b (FM-mode pre-emphasis) — de-scoped from 3M-3a-ii to FM-mode follow-up.
• Multi-panadapter (Phase 3F) — DDC assignment, FFTRouter, PanadapterStack, RX2 enable. Anti-VOX aamix path also waits on this.
• HL2 IoBoardHl2 (Phase 3L) — completed via Phase 3P-E: I2C TLV queue + 12-step state machine + bandwidth-monitor two-pointer byte-rate compute + Longpath throttle-detection layer; P1CodecHl2 now intercepts C&C frames to inject I2C TLV payloads.
• Skin system (Phase 3H), TCI + Spots (Phase 3J), CAT/rigctld (Phase 3K), WAV/IQ recording (Phase 3M-recording).

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Key Features

Working now:

• OpenHPSDR Protocol 1 and Protocol 2 radio discovery, connection, and per-MAC persistence across the full ANAN / Hermes / Metis / Red Pitaya family
• Per-MAC hardware sample-rate selection (P1 up to 192 / 384 kHz; P2 up to 1536 kHz)
• WDSP v1.29 DSP engine — USB/LSB/AM/CW/DIGI/FM demodulation with full RX DSP parity (AGC advanced, EMNR, SNB, APF, 3-variant squelch, NB1/NB2 advanced, RIT/XIT, mute/pan/binaural, frequency lock, mode containers)
• Per-slice-per-band persistence of DSP state (Slice<N>/Band<key>/*)
• Auto AGC-T with noise-floor tracker + MOX guard
• Step attenuator (Classic + Adaptive auto-attenuation) and ADC-overload OVL badge
• Real-time audio output via QAudioSink (48kHz stereo Int16)
• FFTW wisdom caching with first-run progress dialog; audio device selection and persistence
• GPU-accelerated spectrum + waterfall (QRhi — Metal, Vulkan, D3D12, OpenGL fallback); 4096-point FFTW3 FFT, Blackman-Harris window, 30 FPS, FFT-shift + mirror
• Full Setup → Display wiring — 47 Spectrum / Waterfall / Grid controls live on both render paths; 7 colour schemes; per-band grid state across all 14 bands (160m–6m + GEN + WWV + XVTR)
• Clarity Blue waterfall palette + Clarity adaptive auto-tune, Re-tune button, per-band Clarity memory, zoom persistence
• VFO flag widget — 4-tab layout (Audio / DSP / Mode / X-RIT), 4×2 DSP grid, AGC 5-button row, integrated S-meter level bar with dBm readout
• CTUN panadapter — independent pan center and VFO, WDSP shift offsets, bin-subset zoom with hybrid FFT replan, off-screen VFO indicator with double-click recenter
• Filter passband overlay, cursor frequency readout, click-to-tune, scroll-to-tune, filter drag, waterfall pan
• Phase word NCO tuning with Alex HPF/LPF/BPF filters, P1 full 17-bank C&C round-robin
• Dockable / floatable containers with axis-lock, hover-reveal title bar, XML serialization
• GPU-rendered meter engine (QRhi 3-pipeline), 31 MeterItem types, 38+ ItemGroup presets, ANANMM 7-needle with exact Thetis calibration, CrossNeedle dual fwd/rev, Magic Eye, History, Edge mode
• Full Thetis-parity Container Settings Dialog — 3-column layout, per-item property editors (~155 fields), snapshot+revert, container-level Lock/Notes/Highlight/Minimises/Auto-height, Duplicate, Copy/Paste item settings
• MMIO (Multi-Meter I/O) external-data subsystem — UDP / TCP-listen / TCP-client / Serial transports, JSON / XML / RAW formats, endpoint manager, variable picker, 10 fps polled bindings
• VAX multi-channel audio bus — 5 platform backends, Windows virtual-cable auto-detect (VB-Audio / VAC / Voicemeeter / Dante / DAX), MasterOutputWidget, per-slice VAX channel routing
• Interactive button grids — band (14), mode, filter, antenna, tuning step, macro — with hover/click feedback
• Full UI skeleton — 12 applets, 9-menu bar, 47-page SetupDialog, SpectrumOverlayPanel with 5 flyout sub-panels, status bar
• Help → About dialog + 💡 AI-assisted issue reporter wired to the GitHub issue tracker
• SSB voice transmit + speech processing chain (TX EQ + Leveler + ALC + CFC + CPDR + CESSB + Phase Rotator), 21 factory mic profiles, two-tone IMD test
• Per-profile TX bandwidth control + user-editable filter preset store + mode-aware filter grid + TX/RX filter overlay on panadapter and waterfall
• Per-board PA forward-power calibration (Watt Meter / PA Values setup pages, CalibratedPAPower interpolation, SWR protection at every setTxDrive site)
• Connection workflow with state machine + unicast probe + auto-connect-on-launch + disconnect overlay (Phase 3Q)
• Hermes Lite 2 configuration tabs (Hermes Lite Options + I/O Pin State + N2ADR HERCULES + SWL matrix + signed S-ATT range, all per-MAC)
• Status-bar redesign — title-bar connection segment, drop-priority receive badges, ADC overload indicator, station-name anchor, CPU System/App toggle
• GPG-signed cross-platform builds — Linux AppImage ×2 archs, macOS DMG + PKG ×2 archs (Apple Silicon + Intel; Developer ID-signed + notarized in v0.3.0+), Windows portable ZIP + NSIS installer

Planned (see Roadmap):

• Phase 3M-2 CW TX — sidetone, firmware keyer, QSK/break-in (next major TX epic)
• Phase 3M-3b FM-mode work — pre-emphasis (deferred from 3M-3a-ii)
• Phase 3F Multi-Panadapter — DDC assignment (including PS states), FFTRouter, PanadapterStack, RX2 enable. Anti-VOX aamix path also waits on this.
• Phase 3H Skin System — Thetis-inspired skin format with 4-pan support and legacy-skin import
• Phase 3J TCI + Spots — TCI v2.0 WebSocket server, DX Cluster / RBN clients, spot overlay
• Phase 3K CAT / rigctld — 4-channel rigctld, TCP CAT server
• Phase 3L HL2 IoBoardHl2 — delivered via Phase 3P-E: I2C-over-ep2 TLV queue + 12-step UpdateIOBoard state machine + full bandwidth-monitor port with throttle detection.
• Phase 3M Recording — WAV record/playback, I/Q record, scheduled

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Roadmap

Phase 1 — Architectural Analysis ✅

Deliverable	Status
1A: AetherSDR architecture deep dive	Complete
1B: Thetis architecture deep dive	Complete
1C: WDSP API investigation (256 functions mapped)	Complete

Phase 2 — Architecture Design ✅

Deliverable	Status
2A: Radio abstraction (P1/P2, MetisFrameParser, ReceiverManager)	Complete
2B: Multi-panadapter layout engine (5 layout modes)	Complete
2C: GPU waterfall rendering (FFTW3, QRhi, shaders)	Complete
2D: Skin compatibility (Thetis skin import + extended format)	Complete
2E: WDSP integration (RxChannel/TxChannel, PureSignal, thread safety)	Complete
2F: ADC-DDC-Panadapter mapping (signal chain, DDC assignment, bandwidth)	Complete

Phase 3 — Implementation

Phase	Goal	Status
3A: Radio Connection	Connect to ANAN-G2 via Protocol 2, receive I/Q	Complete
3B: WDSP Integration	Process I/Q through WDSP, demodulate audio	Complete
3C: macOS Build	Cross-platform WDSP build + wisdom crash fix	Complete
3D: Spectrum Display	GPU spectrum + waterfall (QRhi Metal/Vulkan/D3D12)	Complete
3E: VFO + Multi-RX Foundation	VFO controls + rewire I/Q pipeline for N receivers + CTUN panadapter	Complete
3G-1: Container Infrastructure	Dock/float/resize/persist container shells	Complete
3G-2: MeterWidget GPU Renderer	QRhi-based meter rendering engine	Complete
3G-3: Core Meter Groups	S-Meter, Power/SWR, ALC presets	Complete
3-UI: Full UI Skeleton	12 applets, 9-menu bar, SetupDialog, SpectrumOverlayPanel	Complete
3G-4: Advanced Meter Items	12 item types + ANANMM/CrossNeedle presets + Edge mode	Complete
3G-5: Interactive Meter Items	14 interactive items + mouse forwarding + ButtonBoxItem base	Complete
3G-6: Container Settings Dialog	3-column Thetis layout + per-item editors + in-place editing + MMIO external-data subsystem + container-level parity	Complete
3G-7: Polish	MMIO clone-path fix + 5 subclass accessor gap fills + NeedleItemEditor QGroupBox grouping	Complete
3G-8: RX1 Display Parity	47 Spectrum/Waterfall/Grid controls wired, Band enum + per-band grid, BandButtonItem 12→14, GPU path polish	Complete
3G-9: Display Refactor	3G-9a audit + Thetis-first tooltips + slider/spinbox refactor; 3G-9b smooth defaults + Clarity Blue palette; 3G-9c Clarity adaptive auto-tune	Complete
3G-10: RX DSP Parity + AetherSDR Flag Port	AetherSDR VfoWidget visual port + 10 WDSP feature slices wired through WDSP with per-slice-per-band persistence	Complete
3G-11: P1 Field Fixes	P1 VFO frequency encoding (raw Hz, not NCO phase word); Red Pitaya / Hermes family C&C bank fixes	Complete
3I: Radio Connector & Radio-Model Port	Full P1 family (Atlas/Hermes/HermesII/Angelia/Orion/HL2), BoardCapabilities registry, ConnectionPanel, HardwarePage 9-tab capability-gated, per-MAC persistence, RadioConnectionError taxonomy	Complete
3G-13: Step Attenuator & ADC Overload	StepAttenuatorController (Classic + Adaptive), P1/P2 adcOverflow emission, OVL status badge, Setup→General→Options page, RxApplet ATT/S-ATT row, per-model preamp items	Complete
3G-14: About + AI Issue Reporter	Help → About dialog, 💡 menu-bar issue reporter with structured prompts submitting to bug_report.yml / feature_request.yml	Complete
3N: Packaging	Consolidated release.yml, /release skill, GPG-signed alpha builds: Linux AppImage ×2 archs, macOS Apple Silicon DMG, Windows portable ZIP + NSIS installer	Complete
3O: VAX Audio Routing	Longpath-native multi-channel audio bus — 5 platform backends + first-run virtual-cable auto-detect (VB-Audio / VAC / Voicemeeter / Dante / DAX) + MasterOutputWidget + Setup → Audio sub-tabs + per-slice VAX channel persistence	Complete
3P: All-Board Radio-Control Parity	8 stacked sub-phases (A-H) delivering: HL2 BPF + S-ATT bug fixes, per-board P1/P2 codec subclasses, Alex-1/2 Filters live-LED sub-sub-tabs, OC Outputs matrix page, Calibration page (incl. freq-correction factor), Antenna Control per-band grid, HL2 I/O (closes Phase 3L), Accessories (Alex/Apollo/Penny), Diagnostics → Radio Status dashboard + 4 sibling sub-tabs, attribution enforcement pipeline. After merge: Longpath's hardware / radio-plumbing / status-readout surfaces are userland-complete vs Thetis — DSP-parameter / Transmit / CAT / Appearance / Keyboard Setup pages are still page shells with disabled controls pending later phases (see the alpha-tester guide for the honest wired-vs-stub breakdown).	Complete
3M-1: Basic SSB TX	TxChannel, mic input, MOX state machine, I/Q output. Sub-phases 3M-1a TUNE-only first RF (PR #144) → 3M-1b SSB voice + mic-jack family (PR #149) → 3M-1c polish + Thetis-faithful semaphore-wake TX pump v3 + HL2 setTxDrive triage + Codex P1/P2 fixes (PR #152).	Complete (shipped in v0.3.0)
3Q: Connection Workflow Refactor	Single ConnectionState state machine + unicast probe (works through Layer-3 VPNs) + Add Radio dialog rebuild (16-SKU model picker) + ConnectionPanel polish + auto-connect-on-launch + spectrum disconnect overlay + status-bar chrome layer (ConnectionSegment / RxDashboard / StationBlock / AdcOverloadBadge / SVG icon system / CPU toggle / min-filtered RTT) + PA voltage formula correction + macOS Developer ID signing + notarization.	Complete (shipped in v0.3.0)
3M-3a-i: TX Speech Processor I	TX EQ (10-band parametric) + TX Leveler + TX ALC. TxChannel WDSP wrappers, TransmitModel schema, MicProfileManager bundles 27 EQ/Lev/ALC keys, 20 Thetis factory mic profiles ported verbatim, AgcAlcSetupPage TX sections, TxApplet [LEV] [EQ] [PROC] toggle row, TxEqDialog modeless editor, SpeechProcessorPage rewrite as TX dashboard.	Complete (shipped in v0.3.0)
3M-3a-ii: TX Speech Processor II	CFC (Continuous Frequency Compressor) + CPDR (Compander Pre-Distortion / drive ratio) + CESSB (Controlled-Envelope SSB) + Phase Rotator. TxChannel wrappers, TransmitModel +15 properties, MicProfileManager +41 keys, 21st mic profile, CfcSetupPage rewrite, TxCfcDialog modeless editor, full ParametricEqWidget Qt6 port (~3160 LOC, used by TxEq + TxCfc dialogs), ParaEqEnvelope (gzip + base64url helper).	Complete (shipped in v0.3.0)
3M-3a-iii: TX Speech Processor III	DEXP/VOX + AM-Squelch (AMSQ) WDSP setters + dialogs.	Complete (shipped in v0.3.2)
3M-3a-iv: Anti-VOX Cancellation Feed	Closes the 3M-3a-iii gap so the anti-VOX gain control actually works. 4 WDSP wrappers, RxDspWorker → TxWorkerThread → TxChannel pump, full grpAntiVOX trio (Enable + Gain + Tau) on Setup → Transmit → DEXP/VOX. Source-selector dropped (Longpath-architectural divergence: VAX is a digital-mode app bus with no mic-feedback path).	Complete (shipped in v0.4.0)
3M-3b: FM-mode TX work	Pre-emphasis (de-scoped from 3M-3a-ii to FM-mode follow-up).	Planned
3M-2: CW TX	Sidetone, firmware keyer, QSK/break-in. Absorbs the HL2 CWX bit-3 follow-up. Next major epic after v0.4.0.	Planned
3M-4: PureSignal	Feedback DDC plumbing on P1 and P2. calcc.c + iqc.c vendored verbatim from Thetis. PureSignal coordinator class. PsccPump driver. Per-board PsDdcConfig. PsForm modeless dialog (Tools → PureSignal). AmpView modeless dialog. Two-tone IMD overlay on the spectrum. PsaIndicatorWidget bottom-banner FB+PS pair. Enabled on every supported P1 and P2 SKU including HL2 (with HL2-specific negative-ATT support, AutoAtt convergence, ATT-on-TX master force-enable, psSampleRate=0 sentinel resolution) and plain Hermes.	Complete (shipped in v0.4.0)
3-Display: Display + DSP-Options refactor	WDSP avenger() and detector() ports. Setup → DSP page (18 controls, RX/TX combo split, in-place filter resize, Filter Impulse Cache, per-mode buffer/filter/filter-type live-apply). Spectrum: Thetis-faithful FFT slider with 7 windows + live bin width, NF-aware grid, Hz/bin auto-zoom override, SpectrumPeaksPage with PeakBlobDetector + ActivePeakHoldTrace, Multimeter page. SettingsSchemaVersion v5 migration.	Complete (shipped in v0.4.0)
3-LiveApply: Live-apply infrastructure	Sample-rate-live coordinator (12-step Thetis-faithful path through SetXcmInrate); active-RX-count coordinator (held for 3F multi-panadapter); HL2 P1 384 kHz parity (mi0bot-authoritative).	Complete (shipped in v0.4.0)
3F: Multi-Panadapter	DDC assignment (incl. PS states), FFTRouter, PanadapterStack, enable RX2	Planned
3H: Skin System	Thetis-inspired skins with 4-pan support + legacy import	Planned
3J: TCI + Spots	TCI v2.0 WebSocket, DX Cluster/RBN clients, spot overlay	Planned
3K: CAT/rigctld	4-channel rigctld, TCP CAT server	Planned
3L: HL2 ChannelMaster.dll port	Delivered via Phase 3P-E	Planned Complete
3M: Recording	WAV record/playback, I/Q record, scheduled	Planned

See docs/MASTER-PLAN.md for the full implementation plan.

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Building from Source

Dependencies

# Ubuntu 24.04+ / Debian
sudo apt install qt6-base-dev qt6-base-private-dev \
  qt6-multimedia-dev qt6-shadertools-dev qt6-svg-dev \
  cmake ninja-build pkg-config \
  libfftw3-dev libgl1-mesa-dev \
  libasound2-dev libjack-jackd2-dev \
  libpipewire-0.3-dev

# Arch / CachyOS / Manjaro
sudo pacman -S qt6-base qt6-multimedia qt6-svg \
  cmake ninja pkgconf fftw \
  alsa-lib jack2 pipewire

# macOS (Homebrew)
brew install qt@6 ninja cmake pkgconf fftw

The bundled PortAudio is built with PA_USE_ALSA=ON and PA_USE_JACK=ON on Linux, so the ALSA and JACK development headers are required at compile time even if you don't use those audio backends at runtime. libpipewire-0.3-dev (≥ 0.3.50) is strongly recommended on PipeWire-default distributions (Ubuntu 24.04+, Fedora 39+, Arch) — without it the Linux audio path falls back from the native libpipewire-0.3 bridge to the older pactl route.

Windows (FFTW3 Setup)

No manual setup required. CMake auto-downloads fftw-3.3.5-dll64.zip on first configure and drops fftw3.h / libfftw3-3.dll / libfftw3-3.def into third_party/fftw3/. Requires network access on the first cmake -B build run; offline builds need to pre-populate those three files by hand.

Build & Run

git clone https://github.com/OE5SOS/Longpath.git
cd Longpath
cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=RelWithDebInfo
cmake --build build -j$(nproc)
./build/Longpath

On first run, Longpath generates FFTW wisdom (optimized FFT plans). This takes ~15 minutes and shows a progress dialog. The wisdom file is cached for subsequent launches.

See docs/MASTER-PLAN.md for the full implementation plan and docs/project-brief.md for the project brief.

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Contributing

PRs, bug reports, and feature requests welcome! See CONTRIBUTING.md for guidelines.

Development environment: Longpath is developed using Claude Code as the primary development tool. We encourage contributors to use Claude Code for consistency. PRs must follow project conventions, pass CI, and include GPG-signed commits.

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Heritage

Longpath stands on the shoulders of these projects:

• Thetis — The canonical Apache Labs / OpenHPSDR SDR console (C# / WinForms). Longpath's feature source.
• AetherSDR — Native FlexRadio client (C++20 / Qt6). Longpath's architectural template.
• WDSP — Warren Pratt NR0V's DSP library. The signal processing engine.
• OpenHPSDR — The open-source high-performance SDR project and protocol specifications.

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License

Longpath is free and open-source software licensed under the GNU General Public License v3.

Longpath is a derivative work of Thetis licensed under the GNU General Public License. It is not affiliated with or endorsed by Apache Labs, FlexRadio Systems, ramdor/Thetis, or the OpenHPSDR project.