Switch between multiple slices using the A..H tab row¶
The FLEX-8600 supports up to eight simultaneous receive slices. The A..H tab row at the top of the RX Controls applet lets you switch which slice the applet is bound to, so you can view and adjust each slice's mode, frequency, filter, and other settings independently.
Before you start¶
- AetherSDR must be connected to a FLEX-8600 radio. The RX Controls applet requires an active radio connection.
- The radio must have more than one slice active. The tab row is hidden when only one slice exists.
- The RX Controls applet must be visible. If it is not, click the RX tray button on the right sidebar to show it.
Steps¶
- Look at the top of the RX Controls applet for the horizontal row of lettered tabs (A, B, C, and so on, up to H).
- Click the tab letter that corresponds to the slice you want to inspect or control.
- Confirm the switch: the Slice badge in the header row updates to show the letter of the newly selected slice, coloured by its slice identity.
- All controls below the tab row — mode, frequency, filter, AGC, AF gain, and others — now reflect and control the selected slice.
What each control does¶
| Control | Behavior | Notes |
|---|---|---|
| Slice tabs (A..H) | Selects which slice the RX applet is bound to; emits sliceActivationRequested. | Row hidden if maxSlices <= 1. clearSliceButtons() tears down all generated tab buttons and restores the static slice badge on disconnect (v0.9.5.1, #2254). Slice 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. The text format is set to rich text to support HTML rendering of the slice letter if needed (Qt RichText, #2606). |
| 🔓 / 🔒 (tune lock) | Toggles tune-lock on the slice; locked slice ignores frequency changes. | Icon flips between open and closed padlock. |
| ANT1 (RX antenna) | Opens a menu listing available antennas; selecting sets the slice's RX antenna. | Populated from the slice's RX antenna list if available, otherwise from the radio's global antenna list. Each menu item stores the antenna name as data and shows a display label. Blue-coloured label. |
| ANT1 (TX antenna) | Opens a menu listing TX-capable antennas; sets the slice's TX antenna. | Red-coloured label. RX-only antenna ports (prefix 'RX') are filtered out. When the radio has not yet reported its antenna list, a fallback heuristic accepts ports starting with 'ANT', 'TX', or 'XVTR'. |
| 2.7K (filter width) | Shows current filter bandwidth. | Updates when filter preset is applied or when the passband widget is dragged. |
| QSK | Lights amber when CW break-in (QSK) is active. | Read-only; controlled via the CW applet Breakin button. |
| TX (badge) | Click to set this slice as the TX slice (calls slice->setTxSlice). | |
| Mode combo | Sets slice mode; reshapes filter and step presets for the new mode. Selecting a real radio mode tears down the WFM software-demod overlay if it was running on this slice. | RADE option requires HAVE_RADE build flag. Slice mode is read before calling setMode() to avoid spurious deactivation when rebinding or when the slice was never in RADE mode. |
| WFM button | Toggles the software FM demodulator on this slice. When enabled, the slice's DAX IQ stream is routed through a Hi-Fi Cable for wideband FM demodulation. | Checkable button; green when active. Tooltip: "Software FM demodulator via DAX IQ → Hi-Fi Cable". Selecting any mode from the Mode combo automatically deactivates WFM on that slice. |
| Frequency label | Displays current VFO frequency with dotted grouping. | Click to switch into edit mode. |
| Frequency edit | Enter MHz and press Enter to tune and recenter; supports kHz/Hz auto-scaling. XVTR-aware: accepts up to 50000 MHz when slice is on an XVTR antenna or when an explicit MHz value above 54 is entered. | Escape cancels the entry, restores the previous frequency, and dismisses the editor (v0.9.0, #1954). Entering a value above 54 MHz that lacks an explicit decimal point is treated as kHz (e.g., 144600 becomes 144.6 MHz). Values above 54 MHz with an explicit decimal point (e.g., 144.600) are treated as MHz and accepted up to 50000 MHz. Emits directEntryCommitted(freqMhz, "rx-direct-entry"). |
| STEP | < / > or mousewheel cycles through per-mode step sizes; emits stepSizeChanged and stepSizeChangedByUser. | Step list depends on slice mode. |
| Filter width presets | Click to apply a preset filter width; right-click to save current width as a preset. | Buttons hidden for FM/NFM/DFM modes; presets are per-mode. The width readout (shared with VfoWidget via RxApplet::formatFilterWidth) uses mode-aware logic so SSB/digital modes display the correct labelled width (#2197). The stepFilterWidth() method walks the per-mode preset list for mode-correct widen/narrow (#2208). |
| Filter passband widget | Drag the lo/hi edges to adjust filter passband; emits filterChanged (lo, hi). | |
| Tone mode (FM) | Selects CTCSS tone mode on FM/NFM/DFM. | Visible only in FM family modes. |
| CTCSS tone value | Selects CTCSS tone frequency sent with transmit. | Enabled only when Tone mode = CTCSS TX. |
| Offset (FM) | Sets FM repeater offset frequency in MHz. | |
| − (offset down) | Sets repeater offset direction to 'down' (TX below RX). | |
| Simplex | Sets repeater offset direction to simplex (TX = RX). | Default setting. |
| + (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 via muteAllToggled signal. Icon flips when the radio acknowledges via SliceModel::audioMuteChanged. | Per the Radio-Authoritative Settings Policy (#2489), mute state is NOT saved/restored on reconnect — the radio is the source of truth for audio mute. The single-click is deferred by clickDiscriminationIntervalMs() (default platform double-click interval, ~400 ms) so a double-click can override it. The double-click handler is in eventFilter and cancels the single-click timer. |
| AF gain | Adjusts slice audio output gain; emits afGainChanged. | Shows tooltip displaying the current percentage value. |
| L / R pan | Pans slice audio between left (0) and right (100) channels. | Double-click resets to 50 (centre). Shows tooltip displaying "C" at centre, "L{offset}" for left pan, "R{offset}" for right pan. The slider fill anchors from the centre outward so the neutral position is visually clear. |
| 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; takes effect only when SQL is on. Disabled in RTTY and digital modes. | The last manually set squelch level is persisted client-side across sessions via the LastManualSquelchLevel setting, so your preference is preserved even if automatic AGC modes adjust the radio's value. |
| AGC mode | Sets the slice AGC mode. | Hidden in FM family modes. |
| 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 automatically set the threshold based on the current noise floor. | Tooltip reflects which value is being adjusted and advertises the right-click calibration feature. |
| RIT | Toggles Receive Incremental Tuning on/off. | |
| RIT 0 | Zeroes the RIT offset. | |
| RIT offset | < / > or mousewheel adjusts RIT offset by 10 Hz steps. | |
| XIT | Toggles Transmit Incremental Tuning on/off. | |
| XIT 0 | Zeroes the XIT offset. | |
| XIT offset | < / > or mousewheel adjusts XIT offset by 10 Hz steps. | |
| ## Digital mode squelch behavior |
Squelch is disabled in RTTY, DIGU, and DIGL modes. When you switch to any of these modes from a non-digital mode:
- The SQL toggle button and squelch level slider become disabled.
- If squelch was on before switching, AetherSDR saves the state and turns squelch off automatically.
- This prevents the squelch from gating weak FSK signals, which would otherwise notch out FSK characters and break decoding (#2504).
Switching away from a digital mode to a non-digital mode restores the previous squelch state.
Manual squelch level persistence¶
Starting in v26.5.2, the last manually set squelch level is saved to the application settings under the key LastManualSquelchLevel and restored on the next launch. This is necessary because the radio's automatic squelch mode can overwrite the slice's squelch level with algorithm-suggested values. AetherSDR preserves your manual preference client-side so it survives mode cycles and application restarts.
RADE mode behavior¶
RADE mode is a client-side only mode. When you select RADE from the Mode combo (available only in builds with the HAVE_RADE flag), the client immediately enters RADE mode and activates the RADE subsystem. The radio itself continues to report the underlying DIGU or DIGL mode.
Because RADE is client-side only, the following is important to understand:
- Mode switch away from RADE: When you switch away from RADE to another mode, the client deactivates RADE mode. The applet emits
radeActivated(false)only if the slice was actually in RADE mode, preventing stale deactivate signals when changing modes on a non-RADE slice (#2376). - Filter presets and step sizes: While in RADE mode, filter and step presets follow DIGU/DIGL conventions.
WFM (Wideband FM) mode¶
AetherSDR includes a software FM demodulator for receiving wideband FM broadcasts (88–108 MHz broadcast band and other WFM signals). This is not a radio mode — it is a client-side overlay that routes the slice's DAX IQ stream through a Hi-Fi Cable for demodulation.
Using WFM¶
- Tune the slice to the desired WFM frequency.
- Click the WFM button next to the Mode combo to enable the software demodulator.
- The button turns green when active.
- To disable WFM, click the button again, or select any mode from the Mode combo — selecting a real radio mode automatically deactivates WFM on that slice.
Important notes¶
- WFM is not a mode entry in the Mode combo. It is a separate toggle button.
- The WFM button is available on all slices. Only one slice can have WFM active at a time per the DAX IQ routing constraint.
- When you select a mode from the Mode combo while WFM is active, the applet emits
wfmActivated(false)with the current slice ID, deactivating the software demodulator.
AGC-T noise calibration¶
The AGC Threshold slider includes a right-click context menu for calibrating the AGC-T value against the noise floor. This helps you set the threshold to an optimal level that avoids squelching valid signals while rejecting noise.
Steps¶
- Tune the slice to a quiet frequency with no signals present.
- Right-click the AGC threshold slider.
- Select Calibrate AGC-T against noise floor… from the context menu