PTT, observe the PWR and SWR of ATU antenna tuner.
ATU button TUNE use: short press (less than 1 second) ATU button, it is in reset state, long press (more than 1 second) ATU button is in tuning state.
If the SWR display of the ATU antenna tuner in the transmitting state is ＞2.0, it means that the antenna is detuned.6.You need to use an 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 will be detuned. In serious cases, it is not recommended to use more than 30W power, and the transmission power should be controlled below 30W; If the tuning is completed, the SWR display is less than 2.0, and the maximum power of 100W can be used for transmission.

Specifications:
Name: ATU100 Tuner
Material: aluminum alloy
Color: black
Display: 0.91inch OLED display
Charge: USB Type-C cable
Battery: 1 * lithium battery, 3.7V, 1500mAh (included)
Voltage: typical + 12 V  (DC10-15V, 13.8V)
Working frequency: 1.8-55MHz
Maximum current consumption: 400mA
Maximum working power: 100W
Maximum possible measurement power: 150W
Minimum power required to starts tuning: 5W
Minimum possible measurement power: 0.1W
Measurement step for power up to 10W: 0.1W
Measurement step with power higher than 10W: 1W
Power measurement accuracy: 10%
Maximum installation inductance: 8.53uH
Minimum installation inductance step length: 0.05uH
Maximum installation capacitance: 1869pF
Minimum installation capacitance step length: 10pF
Number of panel buttons: 3 (ON/OFF, AUTO, TUNE)
Item size: 160 * 90 * 40mm / 6.30 * 3.54 * 1.57in
Item weight: 413g / 0.91lb
Package size: 175 * 122 * 55mm / 6.89 * 4.80 * 2.17in
Package weight: 465g / 1.03lb

Packing List:
1 * ATU100 Tuner
1 * Type-C Cable