Run the internal ATU¶

Use the internal automatic antenna tuner (ATU) to find a low-SWR match on your current frequency. After a successful tune cycle, the ATU stores the result in memory for quick recall.

Before you start¶

AetherSDR must be connected to the radio. The TX applet is not functional without a radio connection.
The TGXL must not be in OPERATE mode. ATU is disabled when TGXL is in OPERATE mode.
Set Tune Pwr to an appropriate level for your antenna before running the ATU. The default is 10.

Steps¶

Click the TX tray button in the right sidebar to open the TX Controls applet if it is not already visible.
Adjust the Tune Pwr slider to the desired tune-carrier power level (0–100; default 10).
Click ATU to start the tuning cycle.
Wait for the tuning cycle to complete. Monitor the Success, Byp, and Mem indicators for the result.

What each control does¶

Control	Kind	Behavior
ATU	Push button	Starts or bypasses the ATU depending on context (see ATU button behavior). Disabled when TGXL is in OPERATE mode.
MEM	Toggle button	Toggles ATU memory recall on/off. Disabled when TGXL is in OPERATE mode.
Tune Pwr	Slider	Sets the tune-carrier power level sent to the radio during tuning.
Success	Indicator	Lights green when the ATU tuning result is successful or OK.
Byp	Indicator	Lights orange when the ATU is in Bypass or ManualBypass.
Mem	Indicator	Lights green when the ATU is using a stored memory.

ATU button behavior¶

Starting with v0.9.5.1, the ATU button toggles between starting a tune cycle and switching the tuner into bypass, depending on the current ATU status and transmit frequency. This mirrors the per-frequency toggle behavior in SmartSDR.

Situation	What `ATU` click does
No previous tune on this frequency, or ATU is not in a Successful/OK state	Starts a fresh ATU tune cycle.
ATU status is Successful or OK, and TX frequency has not changed since the last tune	Switches the ATU into bypass.
ATU status is Successful or OK, but TX frequency has changed since the last tune	Starts a fresh ATU tune cycle.

In practice: - The first click on a new frequency always starts a tune cycle. - After a successful tune, clicking ATU again on the same frequency bypasses the tuner. - Changing frequency resets the toggle, so the next click starts a fresh tune cycle regardless of the previous status. - Entering bypass clears the stored tuned frequency, so the next click always starts a fresh tune.

MOX and Quindar tones (v0.9.7)¶

Starting in v0.9.7, clicking MOX routes through the Quindar-tone coordinator rather than toggling transmit directly. When the QUIN chip is enabled in the Audio Channel Strip and the active TX slice is on a phone mode, clicking MOX to engage transmit plays the K tone and clicking it again to disengage plays the BK tone. When Quindar is disabled or the active TX slice is not on a phone mode, MOX behaves as before and toggles transmit directly.

Tips¶

If Byp lights after the tuning cycle, the ATU was unable to find a match and has bypassed itself. Check your antenna system and SWR before transmitting at full power.
If Mem lights, the ATU applied a previously stored tuning memory rather than running a full tune. This is normal when MEM is enabled and a valid memory exists for the current frequency.
To manually force the tuner into bypass after a successful tune, click ATU a second time without changing frequency.

Troubleshooting¶

ATU button is unresponsive — The radio's TGXL is in OPERATE mode. ATU is disabled in this mode. Switch the TGXL out of OPERATE mode before attempting to tune.
Success indicator does not light after tuning — The ATU may have bypassed (check Byp) or the tune-carrier power may be too low for the ATU to work with your antenna. Increase Tune Pwr and try again.
Clicking ATU bypasses instead of tuning — The ATU status is Successful or OK and the TX frequency has not changed since the last tune. This is the expected second-click bypass behavior. Change frequency to force a fresh tune cycle, or leave the tuner in its current matched state.
Quindar tones do not play on MOX — Confirm that the QUIN chip is enabled in the Audio Channel Strip and that the active TX slice is set to a phone mode. Quindar tones are not played on CW or digital modes.