RX Controls Applet — Full Reference¶

The RX Controls applet provides per-slice receive controls for the currently bound slice. It is displayed as a panel in the right sidebar when the RX tray button is clicked.

XIT usage¶

XIT (Transmit Incremental Tuning) lets you shift your transmit frequency by a fixed number of hertz while your receive frequency stays on the VFO. This is useful when working split, compensating for a TX offset requested by the other station, or matching a net frequency without retuning the panadapter.

Steps¶

In the RX Controls applet, scroll down to the RIT/XIT section.
Click XIT to enable Transmit Incremental Tuning. The button lights when active.
Adjust the XIT offset using one of these methods:
Click the < or > buttons flanking the XIT offset spinbox to step in 10 Hz increments.
Hover over the XIT offset spinbox and scroll the mouse wheel to step in 10 Hz increments.
To return the TX offset to zero without disabling XIT, click XIT 0.
To turn XIT off, click XIT again so the button is no longer lit.

Tips¶

RIT and XIT are independent. You can run both simultaneously: RIT shifts your receive frequency, XIT shifts your transmit frequency, and the VFO readout stays unchanged.
To zero the offset quickly before a transmission, click XIT 0 rather than toggling XIT off and back on.

Troubleshooting¶

XIT controls are greyed out — The radio is not connected. Use Settings > Connect to Radio... to establish a connection, then try again.
TX frequency is not shifting as expected — Confirm the correct slice is selected using the slice tabs (A..H). XIT acts only on the currently bound slice.

Slice tabs (A..H)¶

The slice tab row at the top of the applet lets you select which slice the applet is bound to. Each slice has its own color that persists across sessions. The same color is reflected in the VFO widgets and meter strips for that slice.

Click a tab button (A..H) to bind the applet to that slice.
The tab row is hidden if the radio supports only one slice.
On reconnect, the tab row is rebuilt correctly when the number of available slices changes. The click handler that emits sliceActivationRequested is connected only once per applet instance, regardless of how many times the tab row is rebuilt.
Slice button click connections are guarded against duplicate signal handlers across reconnects. clearSliceButtons() tears down all generated tab buttons and restores the static slice badge on disconnect.

Slice badge¶

The slice badge in the top-left of the applet displays the letter of the currently bound slice (A through H) with its slice-identity color. The badge supports rich text (HTML) rendering for accessibility or special display requirements.

🔓 / 🔒 (Tune lock)¶

Toggles tune-lock on the slice. When locked, the slice ignores frequency changes.

ANT1 (RX antenna)¶

Opens a menu listing available receive antennas. The menu uses the slice's dedicated rxAntennaList() when available, falling back to the global panadapter antenna list. If a KiwiSDR manager is active, virtual antenna tokens from the KiwiSDR are appended to the menu options — these are checked against the assigned KiwiSDR profile for the current slice. Selecting a virtual antenna emits a kiwiRxAntennaSelected signal with the slice ID and profile ID; selecting a real Flex antenna emits flexRxAntennaSelected and calls setRxAntenna() on the slice. Blue-coloured label.

ANT1 (TX antenna)¶

Opens a menu listing TX-capable antennas. RX-only antenna ports (prefix "RX") are filtered out. Red-coloured label.

2.7K (filter width)¶

Displays the current slice filter bandwidth. The readout is shared with the VFO panel and uses mode-aware logic so SSB and digital modes display the correct labelled width. The stepFilterWidth() method walks the per-mode filter preset list to widen or narrow the passband, producing mode-correct edge geometry.

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.

Mode combo¶

Selects the slice mode from the available options: USB, LSB, CW, AM, SAM, FM, NFM, DFM, DIGU, DIGL, RTTY. If the build has RADE support, RADE is also available. DSTR and FreeDV modes are filtered out when the model doesn't support them.

When switching modes: - Switching to RTTY or digital modes (DIGU, DIGL) auto-disables squelch, which would otherwise notch out FSK characters and break decoding. - When switching out of RADE mode, the applet emits a deactivate signal only if the slice was actually in RADE mode, preventing stale deactivate signals when changing modes on a non-RADE slice. - Selecting any real radio mode automatically tears down the WFM software demodulator overlay if it was running on this slice (see WFM button section). - CW mode settings now use a single CW-mode list via isCwMode(), so CWL mode correctly receives the same CW filter presets and step sizes as CW. Previously only the literal mode string "CW" matched.

WFM button¶

A toggle button labelled "WFM" appears immediately after the mode combo box. It enables or disables the software FM demodulator, which uses DAX IQ audio routed through the Hi-Fi cable. This is not a radio mode but a client-side overlay.

Click to toggle the WFM demodulator on or off.
When active, the button is highlighted with a green background.
Tooltip: "Software FM demodulator via DAX IQ → Hi-Fi Cable"
Selecting any mode from the mode combo box automatically deactivates WFM on that slice.
The WFM state is synchronized across reconnects: if the radio connection drops and re-establishes, the button reflects the previously active WFM state.

Frequency label¶

Displays the current VFO frequency with dotted grouping. Click to switch into edit mode. Accessibility: the frequency label emits accessible value change events when the displayed frequency changes, allowing screen readers to announce the new frequency.

Frequency edit¶

Enter a frequency in MHz and press Enter to tune and recenter. Supports kHz/Hz auto-scaling. The input is normalized so that only the first dot is kept as the decimal separator; any additional dots are removed. Escape cancels the entry, restores the previous frequency, and dismisses the editor. XVTR-aware: accepts up to 50,000 MHz when the slice is on an XVTR antenna. The text field is a FreqLineEdit widget with a "MHz" hint label instead of placeholder text. On 2m/70cm (100–999 MHz), a digit-insertion convenience formats values like 1446 as 144.6.

STEP¶

Cycles through per-mode step sizes using < / > buttons or mousewheel. Step list depends on slice mode. The stepSizeChangedByUser signal is emitted alongside stepSizeChanged to distinguish user-initiated step changes from programmatic ones.

Filter width presets¶

Click to apply a preset filter width. Right-click to save the current width as a preset. Buttons are hidden for FM/NFM/DFM modes. Presets are per-mode.

The stepFilterWidth() method walks the per-mode filter preset list to widen or narrow the passband, producing mode-correct edge geometry. CW mode has six presets (50, 100, 250, 400, 500, 600 Hz).

Saved filter presets can store either a plain bandwidth width value or an explicit low-edge/high-edge pair (e.g., 300:3000).

Drag the lo/hi edges to adjust the filter passband.

Tone mode (FM)¶

Selects CTCSS tone mode on FM/NFM/DFM. Visible only in FM family modes.

CTCSS tone value¶

Selects the CTCSS tone frequency sent with transmit. Enabled only when Tone mode is CTCSS TX.

The tone list now includes the 41 standard EIA/TIA-603 tones. Tones that have no standard CTCSS designation letter are displayed by frequency only (e.g., "69.3") instead of being omitted. This includes 69.3, 159.8, 165.5, 171.3, 177.3, 183.5, 189.9, 196.6, and 199.5 Hz.

Offset (FM)¶

Sets the FM repeater offset frequency in MHz (0.0–100.0 MHz, step 0.1).

−, Simplex, + (offset direction)¶

Sets the repeater offset direction to down, simplex, or up.

REV / XFC¶

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 button toggles REV (checkable) normally.
When the connected radio backend advertises hasTransmitFrequencyCheck, the button becomes a momentary XFC down-button. Pressing it emits setTransmitFrequencyCheck(true); releasing it returns to normal.
The held XFC is released on hide, deactivate, capability change, or disconnect.

🔊 / 🔇 (mute)¶

Single-click mutes/unmutes this slice (deferred by the platform click-discrimination interval, configurable in Radio Setup → Slice Controls). Double-click mutes/unmutes all owned slices. The action is deferred by the platform double-click interval so a double-click can override a single-click.

Mute state is NOT saved or restored on reconnect — the radio is the source of truth for audio mute state. The mute icon updates only when the radio acknowledges the mute state change.

AF gain¶

Adjusts the slice audio output gain (0-100).

L / R pan¶

Pans slice audio between left (0) and right (100) channels. Double-click resets to 50 (centre). The slider fill anchors from the centre outward so the operator can see the neutral position at a glance. A small centre-mark dot is painted on the groove.

SQL / 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".

Manual and Auto both turn the radio squelch on.
The auto-squelch algorithm lives in the panadapter; the level is the dB margin above the measured noise floor.
Mirrored by an identical button in the VFO panel's Audio tab.
Disabled (and auto-turned off) in RTTY and digital modes (DIGU, DIGL) where squelch would notch out FSK characters.

Squelch level¶

Adjusts the squelch threshold. Takes effect only when squelch is on. Disabled in RTTY and digital modes.

Manual mode: 0-100 (radio-authoritative per-slice; level is not persisted client-side).
Auto mode: 5-20 dB margin above the measured noise floor; persisted to AutoSqlMarginDb.
Right-click the AGC threshold slider for AGC-T noise calibration.

AGC mode¶

Sets the slice AGC mode (Off, Slow, Med, Fast). Hidden in FM family modes.

AGC threshold¶

Sets the AGC threshold (or AGC off-level when AGC mode is Off). Tooltip reflects which value is being adjusted. Additionally, the tooltip advertises the right-click calibration feature: "Right-click to calibrate against the noise floor."

Right-click on the AGC threshold slider to open a context menu with the option "Calibrate AGC-T against noise floor…" Selecting this emits a calibrateAgcTRequested signal for the current slice, which opens the AGC-T noise calibration panel (disabled while a Kiwi replacement receive is active).

The AGC threshold slider has a right-click context menu that provides access to the noise calibration panel:

Right-click the AGC threshold slider.
Select "Calibrate AGC-T against noise floor…" from the context menu.
The calibration panel opens, allowing you to set the AGC threshold based on the measured noise floor.

This feature helps you set the AGC threshold more precisely for your operating environment. The context menu is only available when a slice is bound to the applet.

RIT¶

Toggles Receive Incremental Tuning on/off.

RIT 0¶

Zeroes the RIT offset.

RIT offset¶

Adjusts the RIT offset by 10 Hz steps using < / > buttons or mousewheel.

XIT¶

Toggles Transmit Incremental Tuning on/off.

XIT 0¶

Zeroes the XIT offset.

XIT offset¶

Adjusts the XIT offset by 10 Hz steps using < / > buttons or mousewheel.

NT mode behavior¶

The NT mode is treated as a digital mode by the RX Controls applet. Specifically:

NT follows the same filter width presets and step sizes as DIGU and DIGL.
The filter width label calculates bandwidth the same way as DIGU (using the high-edge value).
The SQL button and squelch level slider are disabled when NT is active, because audio is routed via DAX and squelch is not meaningful. If squelch was on when you