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Section 16 appendix
| Key | Action |
|---|---|
| Left / Right arrow | Tune ±100 Hz (with Shift, ±10 Hz). |
| Up / Down arrow | Tune ±1 kHz. |
| Page Up / Page Down | Tune ±10 kHz. |
| M | Toggle mute. |
| N | Toggle noise blanker. |
| F | Fit the view to the full receiver span. |
| V | Flip the waterfall (scroll upwards). |
| 1 – 9, 0 (numpad) | Transmit voice-keyer slots 1–10 (nothing if the slot is empty). |
| − (numpad) | Stop a voice-keyer message. |
| Space (CW, with KEY on) | The straight key: carrier while held, and re-bindable as CW straight key in Settings → Controls (2.14). |
| F1 | Open this manual (works even while typing). |
Shortcuts are ignored while typing in a text field.
While this manual is open it takes the scrolling keys for itself, so reading it never tunes the radio at the same time: Up / Down scroll a few lines, Page Up / Page Down scroll a screen, Home / End jump to the ends, and Left / Right step to the previous / next section in the CONTENTS outline. Esc or F1 closes it and the keys go back to tuning.
It opens filling the window, and you can move and resize it from there like any other panel.
Finding something. The bar across the top searches the whole manual as you type. Every occurrence is highlighted where it stands, the one you are on in yellow and the rest in cyan, and the view follows it:
| Key / button | What it does |
|---|---|
| Ctrl+F | Puts the caret in the find field. |
| ▶ or Enter or F3 | Next match (wraps round at the end). |
| ◀ or Shift+Enter or Shift+F3 | Previous match. |
| ✕ or Esc | Clears the search. A second Esc closes the manual. |
The tally beside the buttons reads 3 / 17 — which match you are on, out of how
many there are. In the CONTENTS outline every chapter and subsection holding the
term turns yellow with a count beside it, so a term that only appears in one
chapter out of eleven is visible before you scroll anywhere: search for WSPR
and the outline tells you where it is discussed and how much is said about it.
The search is case-insensitive, so wspr and WSPR find the same things.
These are the defaults. Every one of them can be rebound — and PTT, band changes, filter width and much else bound to keys, mouse buttons or a MIDI controller — on the Controls tab; see 6.4. F1 is the exception: it always opens the manual, so it is not rebindable.
The spoken-announcement actions (6.3) ship with no default keys, since any choice would take a key somebody is already using. Bind them under Speech on the Controls tab:
| Action | What it does |
|---|---|
| Speak status | Reads the whole radio out: band, frequency, mode, VFO, split, and the SWR while keyed. |
| Repeat last announcement | Says the last one again — for the word that a burst of noise landed on. |
| Stop speaking | Stops mid-sentence and drops whatever is queued. |
| Announcements on/off | The master switch, confirmed out loud when switching on. |
| Mode | Description |
|---|---|
| LSB / USB | Lower / upper sideband voice. |
| CW | Morse (continuous wave). Decoded on a waterfall cursor, with type-ahead keyboard sending — see 2.14. |
| AM | Amplitude modulation. |
| SAM | Synchronous AM. Its ECSS-U/ECSS-L filter presets keep one sideband and reject the other — the medium-wave DX trick for ducking an adjacent channel. |
| C-QUAM | C-QUAM, Motorola's AM stereo for the medium wave: AM carrying the sum and the stereo difference as carrier phase, with a 25 Hz pilot for the stereo lamp and the mono blend. Receive only. See cquam-design.md. |
| NFM / WFM | Narrow / wide FM. WFM decodes broadcast stereo and RDS/RBDS automatically. |
| DIGU / DIGL | Data over USB / LSB (general digital). |
| DSB | Double sideband. |
| ISB | Independent sideband: two different signals on one carrier, one on each sideband — a broadcaster's two language services, or voice on one side and a teleprinter on the other. The lower sideband goes to your left ear and the upper to your right, so both can be listened to at once (or one recorded while the other is read). Receive only. |
| DRM | Digital Radio Mondiale — digital shortwave broadcasting. Receive only; decodes the programme audio, the station label and its scrolling text. See 2.19. |
| SPEC | Spectrum only (no demodulation). |
| FT8 / FT4 | Automatic digital modes with decoding, QSO sequencing, and logging. |
| JS8 | JS8 — conversational messaging on FT8's waveform. Four speeds (Normal 15 s / Fast 10 s / Turbo 6 s / Slow 30 s); directed queries, heartbeats and multi-frame free text. |
| WSPR | Weak Signal Propagation Reporter — a two-minute beacon carrying a callsign, grid and power. Not a QSO mode: it measures paths, uploads them to WSPRnet, and feeds the propagation heat map. See 3.11. |
| PI4 | "Next Generation Beacon" — a one-minute four-tone FSK beacon carrying a callsign. Receive only. Not a QSO mode: it measures paths, and carries no grid to feed the propagation heat map with. See 3.20. |
| PSK | PSK31 keyboard mode (BPSK31 / varicode). |
| RTTY | RTTY keyboard mode (Baudot; selectable shift and baud), on a sideband. |
| RTTY-FM | The same modem on an FM carrier, the way a club bulletin is still sent on VHF. |
| NAVTEX | The maritime safety broadcast on 518, 490 and 4209.5 kHz: navigational and meteorological warnings, search-and-rescue bulletins and ice reports, framed into messages. Receive only. |
| DSC | Digital Selective Calling — the marine distress and calling system on VHF channel 70 and the MF/HF distress channels: 1200-baud FFSK carrying distress alerts (MMSI, nature, position, time) and routine calls. Receive only. See 3.21. |
| JT65 / JT9 | The classic WSJT weak-signal modes — 65-FSK (JT65) and 9-FSK (JT9), both in a 60-second slot, carrying <to> <from> <grid|report>. Receive only in this build (no QSO sequencer). See 3.22. |
| FST4 | The slow weak-signal mode for EME, troposcatter and LF/MF: 160-symbol GFSK in a 15/30/60/120/300-second T/R period, carrying the same 77-bit message as FT8/JT65. Receive only in this build. See 3.23. |
| MSK144 | Meteor scatter on 6 m and 2 m: continuous-phase binary MSK at 2000 baud in a 15-second period, carrying the same 77-bit message as FT8. The decoder hunts the period for meteor-trail bursts. Receive only in this build. See 3.24. |
| Q65 | The modern WSJT weak-signal mode for EME, ionoscatter, rainscatter and troposcatter: 65-tone FSK in a 15/30/60/120/300-second T/R period, with a tone-spacing letter A–E for Doppler spread. Carries the same 77-bit message as FT8. Receive only in this build. See 3.25. |
| UVPACKET | A packet protocol for private amateur VHF/UHF groups: a short π/4-DQPSK burst carrying an application byte pipe (app type, sequence, 1–32 payload blocks) rather than a WSJT message. The sub-mode is detected from the preamble. Receive only in this build. See 3.26. |
| JTTY | Experimental. The WSJT-X 3.2 asynchronous RTTY-like text mode: no T/R slots, ~1.888-second frames of 4-GFSK about 125 Hz wide carrying free text or typed contest atoms behind a tail-biting convolutional code. Sends a message once. See 3.28. |
| FSK441 | The original meteor-scatter mode on 6 m and 2 m: 4-FSK at 441 baud carrying free text and the R26/R27/RRR/73 single-tone shorthand, in a 15/30-second period. The decoder hunts the period for meteor-trail pings; transmit repeats the message for the length of the over. See 3.27. |
| OLIVIA | Robust MFSK keyboard mode (selectable tones/bandwidth). |
| THOR | DominoEX-family IFK keyboard mode with FEC (THOR4…THOR32). |
| FSQ | Fast Simple QSO — 33-tone IFK with directed (FSQCALL) messaging and images. |
| HELL | Hellschreiber — facsimile "dot" mode read by eye, not decoded (Feld Hell, Slow, X5, X9, FSK Hell 245/105, Hell 80). |
| SSTV | Slow-scan TV image mode (Scottie, Martin, Robot), on a sideband — LSB on 160/80/40 m, USB above. |
| SSTV-FM | The same picture on an FM carrier, the way slow-scan is sent on VHF and UHF. |
| RIFP | Radio Image Framing Protocol (draft-dulaunoy-rifp-00): packetised images over continuous-phase FSK. Centred on the dial, ~25 kHz wide — 70 cm, 2 m/6 m all-modes, or 10 m FM. |
| RFPAINT | RF Paint — transmit-only spectrum painting of text and images onto the waterfall. |
| RADE | FreeDV RADE V1 — digital voice: a neural codec (Radio Autoencoder) over an OFDM waveform about 900 Hz wide, decoded speech in place of what the receiver hears. On a sideband, and which one follows the band the way phone does — LSB on 160, 80 and 40 m, USB on 60 m, 30 m and above. |
| PACKET / PACKET-HF | AX.25 packet radio: 1200 baud Bell 202 or 9600 baud G3RUH on VHF/UHF FM, 300 baud AFSK on HF sideband. Carries Winlink sessions and offers the modem as a KISS TNC. See 11. |
| APRS | Automatic Packet Reporting System — 1200 baud AX.25 on the region's shared channel, with a live map of every station heard, its own symbol per station, and messages you can send and answer. See 3.12. |
| ADS-B | Aircraft surveillance on 1090 MHz: a target list and a radar picture with history dots, speed vectors and data blocks. Receive only, and needs a receiver streaming at least 2 Msps. See 3.13. |
| VDL2 | The VHF datalink aircraft exchange ACARS over, on fourteen channels between 136.650 and 136.975 MHz at once: a message log and the stations sending them. Receive only. See 3.15. |
| AIS | Ship reporting on the two channels either side of 162.000 MHz at once: a vessel list and a marine chart with hulls drawn to their heading, time-based trails and speed vectors. Receive only. See 3.16. |
| ACARS | Airline datalink on VHF airband, decoded off the AM carrier: aircraft registrations, labels and message text, every message block-checked. Receive only. See 3.18. |
| HFDL | The shortwave aircraft datalink (ARINC 635): ground stations across 2.8–22 MHz talking to aircraft over the ocean, with a decode log and an aircraft map drawn from the positions the aircraft downlink. Receive only, on an HF receiver. See 3.19. |
| ATCHAT | AtCHAT NET — a 2.7 kHz COFDM multi-station keyboard and file mode: dynamic master election, a shared roster, common and directed chat, and block-CRC-ARQ file/image transfer. See 3.17. |
160M, 80M, 60M, 40M, 30M, 20M, 17M, 15M, 12M, 10M, 6M,
4M (Region 1 only), 2M, 1.25M (Region 2 only), 70CM, 33CM (Region 2
only), 23CM, 13CM, 9CM, 6CM — read as 5CM outside Region 1 — and
ALL (general coverage, formerly GEN). Bands your
device cannot receive are disabled in the selector; bands your region does not
have are not offered.
Classic (PowerSDR-style), Viridis, Gray, Icom (Icom-style palette,
peaking at red with no white blow-out), Neon, Synthwave, Matrix, Tron,
Amber (one warm phosphor family, to wear with the Amber Phosphor UI
theme), Rainbow (the full spectrum in order, to wear with the Rainbow
UI theme) and Blue — the traditional blue waterfall SDR# has used since the
beginning and SDR++ inherited: a navy floor rather than a black one, so the
noise keeps its texture, and a top half that runs white, yellow, orange and two
shades of red where the other ramps have already saturated. Chosen on the UI
tab of the Settings window (6.3).
From the User Manual. Home.