Tune the radio by typing a frequency into the VFO panel¶

Direct frequency entry lets you jump to an exact frequency without clicking around the panadapter. Type a value in MHz into the VFO panel's frequency display and press Enter.

Before you start¶

AetherSDR must be connected to your FLEX-8600 radio.
The VFO panel for the target slice must be open. If it is not visible, click the VFO marker flag for that slice on the spectrum display.
The slice must not be locked. A locked slice ignores tune commands.

Steps¶

Click the Frequency display once. The display enters direct entry mode.
Type the desired frequency in MHz.
Press Enter or Tab to apply. The slice retunes immediately.

What happens when you start typing on a locked slice¶

If you click the Frequency display while the slice is locked, AetherSDR immediately exits direct entry mode without applying the frequency. The display shows a brief LOCKED overlay, and the slice remains on its current frequency. Unlock the slice first, then enter the frequency.

What each control does¶

Control	Behavior
RX antenna button	Opens antenna selection menu for the receive antenna of this slice. Menu items use the slice's dedicated RX antenna list when available, falling back to the global antenna list. Right-click available.
TX antenna button	Opens antenna selection menu for the transmit antenna of this slice. Filters out RX-only antenna ports. Menu items use the slice's dedicated TX antenna options when available. Right-click available.
Frequency display	Shows the current slice frequency. Click once to begin direct entry; type MHz and press Enter or Tab to apply. Uses `FreqLineEdit` for enhanced accessibility. Scroll the mouse wheel over the display to step-tune up or down by the current step size.
Slice badge	Shows the slice letter (e.g., A, B, C) in a colored badge. Supports rich text formatting for HTML rendering (#2606). Right-click opens the slice color picker.
Filter width label	Shows current filter bandwidth. Click to cycle through filter preset buttons in the Mode tab. Uses `RxApplet::formatFilterWidth` as the single source of truth, fixing a 0.1 kHz offset that affected SSB/digital mode readouts (#2197, v0.9.8).
AF Gain slider (Audio tab)	Sets the audio output level for this slice. Default: 100. Range: 0-100. Not persisted — reflects live radio state.
Pan slider (Audio tab)	Sets left/right stereo pan for this slice. Default: 50. Range: 0-100. 50 = centre. The slider fill anchors from the centre outward, showing a centre-mark dot on the groove at the neutral position.
Mute button (Audio tab)	Toggle button. Mutes audio output for this slice without changing the AF gain setting. Default: off. Right-click the Audio tab label to toggle mute directly.
Squelch button + slider (Audio tab)	Toggle button. Enables squelch for this slice. The adjacent slider sets the threshold. Default: off. Range: 0-100.
AGC combo (Audio tab)	Sets the AGC attack/release speed for this slice. Options: FAST, MED, SLOW, OFF. Default: FAST.
Mode combo (Mode tab)	Sets the demodulation mode for this slice. Options: USB, LSB, CW, CWL, AM, SAM, DIGU, DIGL, FM, NFM, DFM, RTTY. Default: USB.
Filter preset buttons (Mode tab)	Applies a saved filter width preset. Right-click to save the current filter width into that slot. Custom lo/hi edges can be set per slot via right-click. Persisted in `FilterPresets`.
RIT / XIT buttons + labels (X/RIT tab)	Toggle buttons. Enables receiver (RIT) or transmitter (XIT) incremental tuning. The label shows the current offset; scroll-wheel adjusts in 10 Hz steps. Default: off.
DAX channel combo (DAX tab)	Assigns a DAX audio channel to this slice. Options: Off, 1-8. Default: Off.
Marker thickness button	Cycles the VFO marker line through Off, 1 px, and 3 px. Persisted per slice in `Slice{N}_MarkerWidth`.
Filter edges button	Toggle button. Toggles the filter edge lines on the spectrum passband. Persisted per slice in `Slice{N}_FilterEdgesHidden`. Default: shown.
Collapse toggle	Collapses the VFO panel to a compact frequency-only strip. In collapsed mode, scrolling anywhere on the strip tunes by the current step size. Persisted per slice in `SliceFlagCollapsed_{N}`.

DSP tab controls¶

The DSP tab contains toggle buttons for noise reduction and filtering algorithms supplied by the radio, plus client-side launcher buttons. The following buttons are available in the VFO panel DSP grid:

Button	Description
NR	Noise reduction.
NB	Noise blanker.
ANF	Automatic notch filter.
APF	Audio peak filter. Visible only when the slice is in CW mode.
NR2 / NR4 / RN2 / BNR / MNR / DFNR / NRL / NRS / RNN / NRF	Various noise reduction algorithms. Button availability depends on radio series and build. Right-click NR2, NR4, MNR, or DFNR to open the AetherDSP Settings dialog for that algorithm.
ADSP	Push button. Opens the AetherDSP Settings dialog (client-side NR2 / NR4 / DFNR / RN2 / BNR / MNR). Same entry point as the Settings menu (v0.9.8). Styled like a radio-side DSP toggle but non-checkable.
AetherVoice	Push button. Toggles the Aetherial Audio Channel Strip — the unified TX/RX DSP suite (v0.9.8). Spans 2 columns in the 4-column DSP grid.

All radio-side DSP buttons default to off.

DSP level slider¶

When one or more radio-side DSP algorithms that support a level control are active, a level slider appears below the DSP button grid. The slider label shows the name of the most recently enabled algorithm that supports leveling (for example, NR, NB, ANF, NRL, NRS, NRF, or ANFL). The adjacent numeric readout shows the current value.

Drag the slider to set the level for the targeted algorithm (0–100).
The slider retargets automatically when you enable a different leveled algorithm.
When no leveled algorithm is active, the slider row fades out but remains in position so the button grid does not shift.
In v0.9.8, the slider is now present on launch for any DSP that was saved as enabled in the radio's profile, without requiring manual toggling.

Right-click actions on DSP buttons¶

Right-click any of the following buttons to open the AetherDSP Settings dialog for that algorithm: - NR2, NR4, MNR, DFNR (accessible via ADSP button)

Tab bar¶

The VFO panel uses a tab bar with the following labels: Audio (default), Mode, DSP, X/RIT, and DAX. Click a tab label to switch to that tab's content.

Tab labels are now implemented as QPushButton buttons with keyboard focus support. Use Tab/Shift+Tab to navigate between tabs.
The active tab is highlighted with a cyan underline (#00b4d8). Inactive tabs have a transparent underline and use muted color #6888a0.
Right-click the Audio tab label to toggle mute for the current slice.

RADE info row¶

When RADE (Radio Aided Direction Finding Engine) is active, an information row appears below the frequency display and above the S-meter. It shows:

Element	Description
Callsign	The callsign of the station RADE is tracking.
SNR	Signal-to-noise ratio for the tracked station.
Offset	Frequency offset from the slice center frequency.

The RADE info row is hidden when RADE is inactive. This feature is only available in builds compiled with RADE support.

Indicators¶

Indicator	States	Meaning
TX badge	TX (red), hidden	Shown when this slice is the active transmit slice.
SPLIT badge	SPLIT (amber), hidden	Shown when TX is assigned to a different slice than the active receive slice. The badge text changes to SWAP when the split pair can be exchanged.

The SPLIT badge uses increased contrast for better visibility: default color rgba(255,255,255,120), hover color rgba(255,255,255,180).

Antenna selection¶

The RX and TX antenna buttons show the currently selected antenna for each path. Click either button to open a menu of available antenna selections.

Uses the slice's dedicated RX antenna list when available (for example, on radios that provide separate RX antenna ports per slice).
Falls back to the global antenna list when no slice-specific list is available.
Each menu item shows a human-readable label with antenna numbers extracted from the raw identifier.
Tooltips show the raw antenna identifier.

Filters out RX-only antenna ports automatically.
Uses the slice's dedicated TX antenna options when available.
TX antenna detection looks for identifiers starting with "ANT", "TX", or "XVTR", and excludes identifiers starting with "RX".
Each menu item shows a human-readable label with antenna numbers extracted from the raw identifier.
Tooltips show the raw antenna identifier.

Frequency entry on XVTR bands¶

When operating on transverter (XVTR) bands, the frequency entry logic adapts automatically:

3-digit band convenience: On 2m/70cm bands (100-999 MHz range), a bare integer like 1446 is interpreted as 144.6 MHz. The decimal is inserted after the third digit.
Microwave bands: For 23cm and higher bands (1000+ MHz), a bare integer is treated as the frequency in MHz directly (e.g., 1296 means 1296 MHz, not 129.6 MHz).
Explicit MHz entry on non-XVTR bands: If you type a frequency in MHz that is above 54 MHz (for example, typing "146.520"), AetherSDR now detects the explicit MHz entry and treats the value as MHz rather than attempting kHz/Hz fallback parsing. This allows direct frequency entry for VHF/UHF bands even when the radio profile does not report an XVTR antenna.
The maximum allowed frequency is 50000 MHz for XVTR bands and for explicit MHz entries above 54 MHz. For all other entries, the maximum is 54 MHz.

Frequency entry parsing details¶

When you type a frequency value, AetherSDR parses it as follows:

Periods in the input: Multiple periods (e.g., "14.225.000") are normalized to a single decimal point. The value is then interpreted as MHz.
Values ≤ 54 MHz (HF bands):
Values > 54000 are treated as Hz and divided by 1,000,000.
Values > 54 are treated as kHz and divided by 1000.
Values ≤ 54 are treated as MHz directly.
Values > 54 MHz (VHF/UHF/SHF bands):
If you explicitly typed MHz (by including a decimal point or using the "14.225.000" format), the value is used as MHz directly.
If you typed a bare integer, 3-digit-band convenience parsing applies (see above).
The maximum allowed value is 50000 MHz.

Mouse wheel tuning¶

The scroll wheel tunes the slice when the pointer is over the Frequency display, stepping by the slice's current step size. The wheel direction follows the Reverse mouse wheel setting in Interaction Settings (#3302). When enabled, scrolling up decreases frequency and scrolling down increases frequency. On macOS, inertial scroll events are ignored to prevent unintended tuning after a gesture ends. In collapsed mode, scrolling anywhere on the strip tunes by step size.

When the slice is locked, the scroll wheel does not tune and shows a brief LOCKED overlay instead.

Accessibility¶

The VFO panel includes accessibility enhancements:

The frequency display sends QAccessibleValueChangeEvent notifications when the slice frequency changes, allowing screen readers to announce the updated frequency. A dedicated timer debounces rapid frequency changes to avoid flooding the accessibility system.
Tab labels are implemented as QPushButton controls and are keyboard-focusable. Navigate between tabs using the Tab and Shift+Tab keys.
The frequency edit field uses FreqLineEdit with integrated hint text ("MHz (e.g. 14.225)") instead of placeholder text, providing better screen reader support.

Tips¶

If the panel is collapsed to the frequency-only strip, click anywhere on it to expand it so the Frequency display is accessible for direct entry.
Right-click the slice badge to change its color.
Right-click the Audio tab label to toggle mute without switching tabs.

Troubleshooting¶

Typing has no effect or the LOCKED overlay appears — The