SainSonic RA-07A antenna analyzer is a compact battery powered RF impedance analyzer. It can test the SWR status of your antenna, measure the impedance and reactance component and help you to solve antenna problems. This unit combines six basic parts: a variable oscillator, frequency counter, independent oscillator, 50 ohm RF bridge detector, an A-D converter, and microcontroller. This compact product was built to feed the need for the solid construction and field test. The operating frequency range of this unit goes from HF, and extends up to 490MHz. The operating frequency range of this unit extends from 1.5 to 71 MHz in six overlapping bands, and includes SWR measurements on 85-185MHz, 300-490MHz. Specifications * Band Coverage: 160m, 80m, 40m, 20/30m, 10/15m, 6m, 2m, 70cm * RF Output Level: 2Vpp * SWR Range: 1~9.9 * Impedance Range: 10~500ohm * External Power: DC 10.8~12V * Battery: 8*AA Alkaline Battery (NOT INCLUDED) * Power Consumption: Functions * Signal source * Capacitance meter * Inductance meter * Show reactance value * Show impedance value * SWR value from 1.1 to 9.99 * RF strength meter * Frequency counter Batteries Guide After the cover mounting screws are removed, remove the entire back cover. Battery box is accessed by removing the RA-07A"s cover. Place 8x1.5V (not 1.2V) AA size batteries into the battery box. DO NOT use external power supply when replacing batteries. Note: If you need video instruction, please feel free to contact us. And please download user manual via the below link: https://s3-ap-northeast-1.amazonaws.com/sain-amzn/28/28-020-708/28-020-708.pdf