Tune the radio to a frequency (type MHz in the readout)¶
Type a frequency directly into the RX Controls applet to move the active slice's VFO to any frequency within the radio's tuning range.
Before you start¶
- AetherSDR must be connected to a FLEX-8600 radio. If not, go to
Settings > Connect to Radio.... - The RX Controls applet must be visible. If it is not, click the RX tray button on the right sidebar.
- Make sure the slice you want to tune is not locked. If the lock icon shows 🔒, click it to unlock before proceeding (see Lock the slice to prevent accidental retuning).
Steps¶
- If you have more than one slice, click the appropriate slice tab (A, B, C, etc.) at the top of the RX Controls applet to select the slice you want to tune.
- Click the Frequency label (the dotted readout, e.g.
0.000.000). It switches into edit mode, becoming the Frequency edit field. - Type the desired frequency in MHz. For example, type
14.225for 14.225 MHz. - Press Enter. The slice tunes to the entered frequency and the panadapter recenters on it.
To cancel without changing frequency, press Escape. The editor closes and the previous frequency is restored.
What each control does¶
| Control | Behavior | Default |
|---|---|---|
| Slice tabs (A..H) | Selects which slice the RX applet is bound to. Row hidden if the radio supports only one slice. clearSliceButtons() tears down all generated tab buttons and restores the static slice badge on disconnect (v0.9.5.1, #2254). Button click connections are guarded against duplicate signal handlers across reconnects. | — |
| Slice badge | Displays the letter of the currently bound slice, coloured by slice identity. Supports HTML rendering for custom slice labels (#2606). | A |
| 🔓 / 🔒 | Toggles tune-lock on the slice. Locked slices ignore frequency changes. | 🔓 (unlocked) |
| ANT1 (RX antenna) | Opens a menu listing available RX antennas, including KiwiSDR virtual antenna tokens when a KiwiSDR manager is active. If no antennas are reported, falls back to "ANT1" and "ANT2". Selection differentiates between KiwiSDR virtual antennas (emits kiwiRxAntennaSelected) and FlexRadio physical antennas (emits flexRxAntennaSelected and calls slice->setRxAntenna). |
ANT1 |
| ANT1 (TX antenna) | Opens a menu listing TX-capable antennas. Filters out RX-only ports (prefix 'RX') and includes ANT, TX, and XVTR ports. | ANT1 |
| 2.7K (filter width) | Shows the current filter bandwidth (e.g. 2.7K, 3.3K, 500). Updates when filter preset is applied. | 2.7K |
| QSK | Lights amber when CW break-in (QSK) is active. Read-only; controlled via the CW applet. | off (grey) |
| TX (badge) | Click to set this slice as the TX slice. | — |
| Mode combo | Sets the slice operating mode. Options vary by radio and build flags. RADE option requires HAVE_RADE build flag. Switching to RTTY or digital modes (DIGU, DIGL) auto-disables squelch. When switching out of RADE mode, emits radeActivated(false) only if the slice was actually in RADE (#2376). Selecting any real radio mode also tears down the WFM software-demod overlay if it was active on this slice. | USB |
| WFM | Toggle button. Enables a software FM demodulator using DAX IQ via Hi-Fi Cable. When active, the button background turns green. Selecting any mode from the mode combo automatically deactivates WFM. Corresponding deactivate signal always includes the slice ID. (#2254) | off |
| Frequency label | Displays current VFO frequency with dotted grouping. Click to enter edit mode. Fires an accessible value-change event when the frequency changes and assistive technology is active, using a debounce timer to avoid flooding the accessibility bus. | 0.000.000 |
| Frequency edit | Text field using FreqLineEdit component. Enter frequency in MHz and press Enter to tune and recenter. Supports kHz/Hz auto-scaling. Escape cancels and restores the previous frequency. XVTR-aware: accepts up to 450 MHz on XVTR antennas; accepts explicit MHz entries up to 50,000 MHz when the typed number exceeds 54 MHz (#2376). Hint text shows "MHz" instead of placeholder text. |
— |
| STEP | Sets the step size used when nudging frequency with arrow buttons or mousewheel. Step list depends on mode. User-initiated changes emit stepSizeChangedByUser signal for external synchronization (#2254). |
100 Hz |
| Filter width presets | Click a preset button to apply that filter bandwidth. Right-click to save current width into that slot. Hidden in FM/NFM/DFM modes. The width readout uses mode-aware logic so SSB and digital modes display the correct labelled width (#2197). stepFilterWidth() walks the per-mode preset list for mode-correct widen/narrow (#2208). CW mode presets now include 500 Hz and 600 Hz options. | — |
| Filter passband widget | Drag the lo/hi edges to adjust filter passband directly. | — |
| Tone mode (FM) | Selects CTCSS tone mode on FM/NFM/DFM. Visible only in FM family modes. | Off |
| CTCSS tone value | Selects the CTCSS tone frequency sent with transmit. Enabled only when Tone mode = CTCSS TX. | — |
| Offset (FM) | Sets FM repeater offset frequency in MHz (0.0–100.0 MHz, step 0.1). | 0.0 MHz |
| − (offset down) | Sets repeater offset direction to 'down' (TX below RX). | — |
| Simplex | Sets repeater offset direction to simplex (TX = RX). | checked |
| + (offset up) | Sets repeater offset direction to 'up' (TX above RX). | — |
| REV | Inverts the TX offset sign to work a reversed repeater pair. | — |
| 🔊 / 🔇 (mute) | Single-click mutes/unmutes this slice (deferred by the platform click-discrimination interval). Double-click mutes/unmutes all owned slices. Icon flips when the radio acknowledges via SliceModel::audioMuteChanged. Mute state is NOT saved/restored on reconnect — the radio is the source of truth. | 🔊 (unmuted) |
| AF gain | Adjusts slice audio output gain (0–100). | 70 |
| L / R pan | Pans slice audio between left and right channels (0–100). Double-click resets to 50 (centre). The slider uses centre-anchored fill: the groove is coloured from the centre outward to the handle position, providing a visual indication of the pan direction. A centre-mark dot indicates the neutral position at a glance. | 50 |
| SQL | Enables the squelch at the current slider level. Disabled (and auto-turned off) in RTTY and digital modes (DIGU, DIGL) where squelch would notch out FSK characters (#2504). | — |
| Squelch level | Adjusts squelch threshold (0–100). Takes effect only when SQL is on. Disabled in RTTY and digital modes. Manual level persists across sessions. | 20 |
| AGC mode | Sets slice AGC mode: Off, Slow, Med, Fast. Hidden in FM family modes. | Med |
| AGC threshold | Sets AGC threshold (or AGC off-level when AGC mode is Off). Right-click the slider to open a context menu and select "Calibrate AGC-T against noise floor…" to calibrate the AGC-T threshold against the current noise floor. The tooltip indicates this right-click option is available. | 65 |
| RIT | Toggles Receive Incremental Tuning on/off. | — |
| RIT 0 | Zeroes the RIT offset. | — |
| RIT offset | Adjusts RIT offset by 10 Hz steps using arrow buttons or mousewheel. | +0 Hz |
| XIT | Toggles Transmit Incremental Tuning on/off. | — |
| XIT 0 | Zeroes the XIT offset. | — |
| XIT offset | Adjusts XIT offset by 10 Hz steps using arrow buttons or mousewheel. | +0 Hz |
WFM software FM demodulator¶
From v26.6.3, the RX Controls applet includes a WFM toggle button for software FM demodulation. This feature uses DAX IQ audio routed through a Hi-Fi Cable to provide wideband FM reception.
To use WFM: 1. Select a slice and tune to a broadcast FM station (typically 88–108 MHz). 2. Click WFM to enable the software demodulator. The button turns green when active. 3. To disable WFM, click WFM again or select any mode from the mode combo. Selecting a mode from the mode combo automatically tears down the WFM overlay.
The WFM button state is synchronized across reconnects and slice bindings via the setWfmActive() method, which receives the slice ID and updates the button only if it matches the currently bound slice.
Filter width stepping¶
From v0.9.8, the applet supports precise mode-correct filter-width stepping through the per-mode preset list. The stepFilterWidth() method walks the preset list for the current mode, finds the nearest preset to the current filter width, and applies the next or previous preset in the direction chosen.
This means:
- Widen and narrow shortcuts produce filter widths that match the current mode's preset list (SSB, CW, AM, digital, etc.).
- The filter width update uses
applyFilterPreset(), which calculates correct low-edge and high-edge geometry for the mode (USB, LSB, CWL, CZU, DIGL, DIGU, RTTY, AM, SAM, etc.). - No filter change occurs if the slice has no filter widths configured or if the current width already equals the target width.
The filter width readout (shared with VfoWidget via RxApplet::formatFilterWidth) uses mode-aware logic so SSB and digital modes display the correct labelled width.
CW mode presets now include 500 Hz and 600 Hz options in addition to the existing 50, 100, 250, and 400 Hz presets.
KiwiSDR virtual antenna integration¶
From v26.7.4, the RX antenna menu integrates with KiwiSDR virtual antennas when a KiwiSDR manager is active. The menu displays both physical FlexRadio antennas and KiwiSDR virtual antenna tokens. Selected virtual antennas emit the kiwiRxAntennaSelected signal with the slice ID and KiwiSDR profile ID, while physical antennas emit flexRxAntennaSelected and call slice->setRxAntenna().
The antenna menu is now owned by the RX antenna button and automatically deletes itself when hidden.
Accessibility improvements¶
From v26.7.4, the frequency label fires accessible value-change events when the frequency changes and assistive technology is active. A debounce timer prevents flooding the accessibility bus with rapid updates. The previous frequency text is tracked to avoid sending duplicate events.
Slice tab and badge colors¶
From v0.9.3, slice tab buttons and the Slice badge indicator take their border, active background, and text color from the SliceColorManager singleton rather than a fixed color table. Colors are configurable per slice, persist across sessions, and are reflected consistently in the slice tab buttons, the Slice badge, VFO widgets, and meter strips.
From v26.5.2.1, the Slice badge supports HTML rendering (setTextFormat(Qt::RichText)), allowing custom slice labels with rich text formatting.
Slice tab row behavior on reconnect¶
From v0.9.5.1, the slice tab row is rebuilt correctly whenever the number of available slices changes — for example, after a disconnect and reconnect or when the radio reports a different slice count. The previous implementation skipped rebuilding if any tab buttons already existed, which could leave stale buttons on screen.
The updated behavior works as follows:
- If the new slice count matches the number of existing tab buttons, the row is left unchanged