XIEGU G90 Operation Manual page 22

Automatic Antenna Tuner
This G90 is integrated with an efficient automatic antenna tuner that can
help you quickly set up and debug your antenna.

Short press the [TUNE] button, will be connected to the built-in antenna
tuner, the "TUNE" logo will be displayed at the top of the screen.

When connected to the automatic antenna regulator, press the [TUNE]
button for 1 seconds and the ATU auto-tuning function will be activated.
The receive status is automatically returned when tuning is complete.
Note
1. Press the [TUNE] button and the antenna icon appears at the top of the screen to indicate that the automatic antenna
tuner function is turned on. Just open, the automatic Antenna tuner tuning has not been started.
2. To use the built-in automatic antenna tuner, you must tune once after you turn on the Automatic Antenna tuner feature.
If you start the transmission after tuning, the "SWR" icon will appear on the top of the screen and flash, which means
3.
That the standing wave of the current antenna is still large and needs to be retuned.
4. When the antenna naturally resonates into the current band, be sure to turn off the Automatic Antenna tuner feature.
5. When using a whip antenna and turning on the built-in antenna tuner for tuning, it is possible to cause strong RF
interference to the native or electronic device.
Operating
Tuner
21