The RX Controls applet gives you per-slice control over every receive parameter: mode, frequency, antenna selection, filter width, AGC, audio, squelch, RIT/XIT, and FM repeater settings. Open it whenever you need to configure how a slice receives or transmits.
The RX applet is always present in the Applet Panel (right sidebar). Toggle its visibility with the RX tray button. When the radio supports more than one slice, a row of slice tabs (A through H) appears at the top; clicking a tab binds the applet to that slice. All controls below the tab row affect the currently selected slice only.
Filter width presets are the one setting that persists across sessions, stored under the FilterPresets key. Every other control reflects live radio state and is not independently saved by AetherSDR.
Select which slice the applet controls. The tab row is hidden when the radio has only one slice. On disconnect, clearSliceButtons() tears down all generated tab buttons and restores the static slice badge. Slice button click connections are guarded against duplicate signal handlers across reconnects (v0.9.5.1, #2254).
Slice badge
A
Displays the letter of the active slice. Color is driven by slice identity. Read-only.
🔓 / 🔒
🔓 (unlocked)
Toggles tune-lock. A locked slice ignores frequency changes from the panadapter and other sources.
USB, LSB, CW, AM, SAM, FM, NFM, DFM, DSTR, DIGU, DIGL, RTTY (+ RADE if HAVE_RADE build flag is set; WFM via VFO-flag button)
Sets slice mode. Changing mode reshapes filter and step presets automatically. When switching to RTTY or digital modes (DIGU, DIGL) squelch is auto-disabled to prevent notching out FSK characters (#2504). When switching out of RADE mode via the mode combo, the applet emits radeActivated(false) only if the slice was actually in RADE (#2376), preventing stale deactivate signals when changing modes on a non-RADE slice. Selecting a real radio mode also tears down any active WFM software-demod overlay on this slice. DSTR and FreeDV modes are filtered out when the model doesn't support them.
WFM button
—
—
Toggles the software FM demodulator (WFM) on or off for this slice. Uses DAX IQ via Hi-Fi Cable. Active when checked (green background). Selecting any real radio mode from the mode combo automatically deactivates WFM for this slice.
Frequency label
0.000.000
—
Displays the current VFO frequency with dotted grouping. Click to enter edit mode.
Frequency edit
—
0.001–54.000 MHz (up to 50000.000 MHz on XVTR, or when entry exceeds 54 MHz and is explicit MHz)
Type a frequency in MHz and press Enter to tune and re-center. Supports kHz/Hz auto-scaling: entries above 54000 are treated as Hz, above 54 as kHz (unless the entry is explicit MHz). On XVTR antennas, 3-digit 2m/70cm band shortcuts are supported (e.g. 1446 → 144.6 MHz). Press Escape to cancel and restore the previous frequency. Frequency entry uses FrequencyEntryParser::normalizedMhzText() and isExplicitMhzEntry() for consistent parsing across the app.
Click the left/right triangle buttons or use the mouse wheel to cycle through step sizes. The available steps change with mode. Both the stepSizeChanged and stepSizeChangedByUser signals are emitted when the user changes the step.
Opens a menu of available antennas. The menu is populated from the radio's antenna list plus any KiwiSDR virtual-antenna tokens from the Kiwi manager. Selecting a Flex antenna sets the slice RX antenna; selecting a KiwiSDR virtual antenna routes to the assigned KiwiSDR receiver profile. Falls back to ANT1/ANT2 when the list is empty. Label is blue.
ANT1 (TX antenna)
ANT1
Opens a menu of TX-capable antennas. RX-only antenna ports (names starting with "RX") are filtered out. Selecting an item sets the TX antenna. Label is red.
Click a button to apply that width. Right-click to save the current filter width as a preset. Buttons are hidden in FM, NFM, and DFM modes. Presets are stored as either a plain width value or a lo:hi passband pair; both formats are read and written correctly (v0.9.5.1, #2259).
Filter width label
2.7K
—
Shows the current filter bandwidth. Updates when a preset is applied or the passband is dragged. Read-only. The formatting logic is shared with VfoWidget via RxApplet::formatFilterWidth() and uses mode-aware logic so SSB/digital modes display the correct labelled width (#2197).
Filter passband widget
—
—
Drag the low or high edge to set a custom filter passband.
Widen (shortcut action)
—
—
The stepFilterWidth(+1) method walks the per-mode preset list to widen the filter passband with mode-correct edge geometry. Accessible via keyboard shortcut (v0.9.8, #2208).
Narrow (shortcut action)
—
—
The stepFilterWidth(-1) method walks the per-mode preset list to narrow the filter passband with mode-correct edge geometry. Accessible via keyboard shortcut (v0.9.8, #2208).
Sets the AGC response speed. Hidden in FM family modes.
AGC threshold
65
0–100
Sets the AGC threshold. When AGC mode is Off, adjusts the AGC off-level instead. Right-click on the slider to open a context menu with a "Calibrate AGC-T against noise floor…" option (disabled while a Kiwi replacement receive is active).
Single-click mutes/unmutes this slice. Double-click mutes/unmutes all owned slices. The icon updates only when the radio acknowledges (per Radio-Authoritative Settings Policy, #2489). The single-click action is deferred by the platform double-click interval (default ~400 ms) so a double-click can override it. Mute state is NOT saved/restored on reconnect — the radio is the source of truth for audio mute.
AF gain
70
0–100
Adjusts the slice audio output level. Displays a "X%" tooltip with the current percentage value.
L / R pan
50
0–100
Pans audio between left (0) and right (100) channels. Displays "L##", "C" (centre), or "R##" tooltip. Double-click to reset to centre (50). The slider fill anchors from the centre outward, with a centre-mark dot painted on the groove for visual reference.
SQL / AUTO
Off
Off, SQL (Manual), AUTO
Three-way cycle button: each click steps Off → SQL (manual threshold) → AUTO (algorithm tracks the noise floor) → Off. In AUTO mode the button shows amber 'AUTO'; in manual mode green 'SQL'. Disabled (and auto-turned off) in RTTY and digital modes (DIGU, DIGL) where squelch would notch out FSK characters (#2504). Mirrored by an identical button in the VFO panel's Audio tab.
Squelch level
20
Manual: 0–100 (or 0–99 on Kiwi replacement receive); Auto: 5–20 dB margin
In Manual mode adjusts the squelch threshold (takes effect only when squelch is on). In AUTO mode sets the dB margin above the measured noise floor where the gate opens, persisted to AutoSqlMarginDb. In Manual mode the level is radio-authoritative per-slice (not persisted); in Auto mode the margin is persisted. Disabled in RTTY and digital modes and in Off mode. Right-click the AGC threshold slider for AGC-T noise calibration.
The following DSP filter buttons are visible in non-FM modes. Button availability depends on the radio series.
Button
Availability
Behavior
NR
All series
Enables noise reduction. Hidden in FM family modes.
NR2
All series
Enables noise reduction mode 2. Hidden in FM family modes.
NB
All series
Enables noise blanker. Hidden in FM family modes.
NRL
All series (including 6000-series)
Enables noise reduction (NRL algorithm). Hidden in FM family modes. Available on 6000-series radios as of V0.9.4; previously required 8000-series firmware.
NRS
8000-series only
Enables NRS noise reduction. Hidden in FM family modes.
RNN
8000-series only
Enables RNN noise reduction. Hidden in CW and FM family modes.
NRF
8000-series only
Enables NRF noise reduction. Hidden in FM family modes.
These controls are visible only when the slice mode is FM, NFM, or DFM.
Control
Default
Valid range
Behavior
Tone mode (FM)
Off
Off, CTCSS TX
Selects whether a CTCSS tone is sent on transmit.
CTCSS tone value
—
67.0–254.1 Hz (41 standard EIA/TIA-603 tones)
Selects the CTCSS tone frequency. Active only when Tone mode is CTCSS TX.
Offset (FM)
0.0 MHz
0.0–100.0 MHz (step 0.1)
Sets the FM repeater offset frequency.
− (offset down)
—
—
Sets the TX frequency below the RX frequency by the offset amount.
Simplex
checked
—
Sets TX and RX to the same frequency (no offset).
+ (offset up)
—
—
Sets the TX frequency above the RX frequency by the offset amount.
REV / XFC
—
REV (toggle) or XFC (momentary)
For FM repeater operation, REV inverts the TX offset sign to work a reversed repeater pair. On backends that support a transmit-frequency check, the button relabels to XFC: pressing it holds the transmit frequency check for the duration of the press, and while held it briefly forces the radio toward the transmit frequency to confirm coverage. The held XFC is released on hide, deactivate, capability change, or disconnect.
Connects to an Antenna Genius device at the specified IP and port. The "Connected" status is shown only when the connected device is an Antenna Genius proper. If the connection is actually to a ShackSwitch, the AG row shows as disconnected and the ShackSwitch row shows as connected instead.