FlexControl Tuning Knob

The FlexRadio FlexControl is a USB tuning knob with a weighted encoder, three Aux buttons and a push on the knob. AetherSDR detects it automatically and uses it for smooth tuning with acceleration. The buttons can also switch the knob to other jobs (RIT, XIT, volume, AGC-T, APF, CW speed, RF power) or run actions such as MOX, split or CWX macros.

The FlexControl is a host device: it plugs into your computer, so its settings stay available whichever radio you connect. Actions a radio cannot perform are refused with a notice.

AetherControl is an on-screen copy of the FlexControl that works with or without the physical knob (see Using AetherControl below).

Requirements

• FlexControl USB tuning knob (FlexRadio accessory)
• AetherSDR built with Qt serial-port support

The FlexControl is a USB serial device (VID 0x2192, PID 0x0010) running at 9600 baud 8N1. No special driver is needed.

Setup

Open Settings → Radio Setup... → Serial & Controllers and find the FlexControl Tuning Knob group. Shortcuts straight to it: Settings → FlexControl Knob & Buttons..., or the Settings… button in the AetherControl window.

Control	What it does
Status	"Not detected", or the port it is connected on
Detect / Close	Look for the knob now and open it / release it
Button 1–3, Knob Button: Tap and Double	The action for a single and a double press of each button
Auto-detect on startup	Find and open the knob at launch (on by default)
Invert tuning direction	Reverse the knob

If you plug the knob in after launch, click Detect.

Using the knob

The encoder reports its own acceleration (1–6 steps per detent depending on how fast you turn). Each step is the current tuning step from the RX applet (10 Hz, 100 Hz, 1 kHz, …), so change the step size to change the tuning resolution.

Wheel modes

Actions whose name starts with Wheel do not fire once: they change what the knob does. Tap a button bound to, say, WheelRit, and turning the knob now adjusts RIT; the button's LED shows which mode is active. Press the knob, or tap a button bound to an ordinary action, to return the knob to tuning.

Upgrading from an older version: the FlexControl volume action drives Master Volume, not the active slice's volume. The older WheelMasterAf action has been merged into it, and saved bindings that use it keep working as Master Volume. Use WheelSliceAudio for per-slice volume (#2925, #2986).

Using AetherControl (virtual FlexControl)

Settings → AetherControl... opens AetherControl, a "Virtual Tuning Controller" window laid out like the FlexControl. It shares its button assignments with the physical knob and mirrors it when one is connected.

• Wheel: double-click the knob to capture the mouse for circular tuning; double-click again to release (Esc also releases). A single fast mouse jump moves the wheel by at most 15°, and the wheel only coasts after a real flick.
• Aux1–Aux3 and PUSH, each with a Single Tap and Double Tap action, from the action list below.
• Wheel Tightness (Tight ↔ Loose, default 45) and Mouse Sensitivity (Less ↔ More, default 50).
• Auto Spin animates the wheel when the slice frequency changes from elsewhere. Reverse reverses the tuning direction of both the virtual and the physical knob.
• Compact hides the configuration controls for a smaller window, which also suits short displays. The window is kept within the screen.
• Settings… opens the FlexControl Tuning Knob group in Radio Setup.

Reference

Default button actions

Button	Tap	Double
Button 1	StepUp	StepDown
Button 2	ToggleMox	ToggleTune
Button 3	ToggleMute	ToggleLock
Knob Button	StepUp	StepDown

Action list

Radio Setup lists actions by their internal names:

Action	What it does
None	Nothing
StepUp / StepDown	Next larger / smaller tuning step
ToggleMox	MOX on/off
ToggleTune	TUNE on/off
ToggleMute	Mute on/off
ToggleLock	Tune lock on/off
BandZoom / SegmentZoom	Band zoom / segment zoom
NextSlice / PrevSlice	Change the active slice
SplitActiveSlice	Split the active slice
SplitMonitorTx	Monitor the TX frequency
ToggleAgc	Cycle AGC mode
ToggleApf	APF on/off
VolumeUp / VolumeDown	Slice audio up / down
ClearRit / ClearXit	Zero the RIT / XIT offset
CwxF1 … CwxF12	CWX macro 1–12; follows the active slice's mode, so in voice modes it fires the matching DVK slot
WheelFrequency	Knob tunes the slice
WheelVolume	Knob sets Master Volume
WheelSliceAudio	Knob sets the active slice's audio volume
WheelHeadphoneVolume	Knob sets headphone volume
WheelRit / WheelXit	Knob adjusts RIT / XIT
WheelAgcT	Knob adjusts AGC threshold
WheelApf	Knob adjusts APF level
WheelCwSpeed	Knob adjusts keyer speed
WheelPower	Knob adjusts RF power

Known issues

• Pressing the knob always returns it to tuning, even when the knob button is bound to another action such as MOX (#2350).
• On Windows the FlexControl is sometimes not detected until it is unplugged and plugged back in (#4276).
• Volume up/down and the volume wheel start from the saved master volume, not the level of the audio path you are hearing, so the first step can jump (#6132).

Troubleshooting

FlexControl not detected

The knob is not plugged in, or your user cannot open the serial port.

1. Check that it is plugged in: on Linux, ls /dev/ttyUSB* should show a device and lsusb | grep 2192 should list the FlexControl.
2. On Linux your user must be in the serial-port group:

   sudo usermod -aG uucp $USER     # Arch
   sudo usermod -aG dialout $USER  # Debian/Ubuntu

   Log out and back in for the change to take effect.
3. Click Detect in Settings → Radio Setup... → Serial & Controllers.

The knob stopped after a USB glitch

The knob's serial port dropped. AetherSDR notices this and re-detects the knob about every 2 seconds, so it comes back on its own, on Windows possibly on a different COM port.

1. Wait a few seconds for the knob to come back.
2. Turn on the Ext Devices log category (see Support and Logging) to see the serial error.

Tuning is too fast or too slow

The knob multiplies the tuning step by its acceleration (1–6×).

1. Change the step size in the RX applet.

Buttons don't work

The button actions may have been set to None, or the knob is in a wheel mode.

1. Check the button actions in Settings → Radio Setup... → Serial & Controllers → FlexControl Tuning Knob.
2. If the knob adjusts RIT or volume instead of tuning, it is in a wheel mode: press the knob to return it to tuning.

See also

• USB Control Surfaces: RC-28, PowerMate, Contour Shuttle, Stream Deck+ and serial keying
• Ulanzi Dial
• MIDI Controller Mapping
• Keyboard Shortcuts