The shortwave automatic antenna tuner contains a set of 7 capacitors and 7 coils, which allows it (at the largest configuration) to work effectively in a wide frequency band, coinciding with the amateur HF band 1.8-30MHz. Built-in lithium battery, 3,7V, 1800mAh, you can use Type-C cable to charge it. Equipped with 0.91 inch OLED display, you can see the data clearly. Automatically tuned and requiring no control wires, suitable for most radio stations. You can try. Features: The shortwave automatic antenna tuner contains a set of 7 capacitors and 7 coils, which allows it (at the largest configuration) to work effectively in a wide frequency band, coinciding with the amateur HF band 1.8-30MHz. Made of material, wear-resistant, with stable and reliable performance. Built-in lithium battery, 3,7V, 1800mAh, you can use Type-C cable to charge it. Equipped with 0.91 inch OLED display, you can see the data clearly. Automatically tuned, no human and control wires are required, and it is suitable for most radio stations. One button to turn on or off, easy to use, very convenient. Instructions: Connect the radio, ATU antenna tuner and antenna. The first time you use it, you need to set the output power of the radio or power amplifier in the range of 20-30W, otherwise high-power tuning can easily damage the antenna tuner. Set radio mode, use frequency modulation mode. Select the antenna band to use, use 20-30W power in frequency modulation mode, press PTT radio, observe PWR and SWR of ATU antenna tuner. ATU button Use TUNE: short press (less than 1 second) ATU button, 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 out of tune. 6. You need to use an antenna tuner. Press and hold the ATU tune button 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 After tuning, the SWR display is less than 2,0, and the maximum power of 100W can be used for transmission. Technical data: Name: ATU100 Tuner Material: aluminum alloy Colour black Display: 0.91 inch OLED display Charge: USB Type-C cable Battery: 1 x Lithium battery, 3,7 V, 1800 mAh (included) Voltage: typical 12V (DC10-15V, 13,8V) Operating Frequency: 1,8-55 MHz Maximum current consumption: 400mA Maximum working power: 100 W Maximum possible measurement power: 150W Minimum power required to start tuning: 5W Minimum possible measurement power: 0,1W Measuring step for power up to 10W: 0.1W Measuring step above 10W: 1W Power measurement accuracy: 10 percent Maximum installation inductance: 8.53uH Minimum installation inductance step length: 0,05uH Maximum installation capacity: 1869pF Minimum installation capacity step length: 10pF Number of panel buttons: 3 (ON or OFF, AUTO, TUNE) Product Size: 160x90x40mm or 6,30x3,54x1,57inch Product Weight: 413g or 0.91lb Package Weight: 465g or 1,03lb List of things to pack: 1 x ATU100 Tuner 1 x Type-C cable Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.