1. Connect the ATU antenna tuner. For first-time use, set the output power of your radio or power amplifier to between 20-30W. Warning: High-power tuning can damage the antenna tuner.2. Set the radio to FM mode. Select the desired antenna frequency. In FM mode, use 20-30W power. Press the radio PPT button and observe the PWR and SWR on the ATU antenna tuner.3. Using the ATU button TUNE: Press the ATU button briefly (less than 1 second) to reset. Press and hold (more than 1 second) to adjust.4. If the SWR on the ATU antenna tuner is greater than 2.0 in transmission mode, the antenna is detuned. You need to use the antenna tuner. Press and hold the ATU button TUNE to tune and observe the SWR value. If the SWR is greater than 3.0 after tuning, the antenna is detuned.5. Honestly, it is not recommended to use more than 30W of power. The transmission power should be controlled below 30W. If the tuning is complete and the SWR is less than 2.0, the maximum power of 100W can be used for transmission.ATU Antenna Tuner Product Specifications:1. 0.96-inch OLED Auto Sky Adjustment2. 0.96-inch Auto Sky Adjustment3. Weight: 520g4. Package Dimensions: 19.5*13*6CMKey Features of the ATU-100 MINI 7x7 Antenna Auto Tuner:Operating Frequency: 1.8-55 MHzBuilt-in 3.7V 2000MA Lithium BatteryUSB Charging Current: 1AMaximum Operating Power: 100WMaximum Measurement Power: 150W1 Watt: Minimum power required to start settingMinimum Measurement Power: 0.1WMeasurement Program Up to 10W: 0.1WPowerful Measurement Steps of 10W per Hour, Higher than STI: 1WPower Measurement Accuracy: 10%Rated Maximum Inductance: 8.4 uH CapacitanceMinimum mounting step for inductors: 0.05μHMaximum installed capacity: 1870pF capacitorMinimum mounting step length: 10Color: BlackMaterial: Plastic+MetalPackage Contents:1* Automatic antenna tuner1* USB cableOnly the above package content, other products are not included.Note: Light reflection and different displays may