USB RF Tester ABS Radio Frequency Power Meter with 4Pcs Antenna 5VDC -45~+15dBm Item Type: USB RF tester Material: ABS Measuring Power Range: -45~+15 dBm (0 to -40dBm has good linearity) Measurement Power Resolution: ±0.1 dBm Measuring Frequency Range: LF~10000 MHz (different models have different frequency ranges) Input Impedance: 50Ω5 Dynamic Range: > 60dB Working Voltage: 5VDC (powered via USB) Charging Current: 500mA RF Common Sense: DB is a Pure Counting Unit: For power dB = 10 x lg (A / B) For voltage or current, dB = 20 x lg (A / B) DBm defines milliwatts. 0 dBm = 1 megawatt Does DBw define wattage? 0 dBw = 10lg1 w = 10lg1000 mw = 30 dBm. By default, dB always defines the power unit, and the calculation unit is 10lg. Of course, in some cases, signal strength (amplitude) can be used to describe work and power. In this case, please use 20LG as a meter. This applies to the field of control and signal processing. For example, sometimes you can see the expression of dBmV. Applications: Radio frequency instrument calibration; radio frequency equipment testing and maintenance; measuring the standing wave ratio of radio frequency circuits (adding a feedback bridge); measuring the return loss of radio frequency circuits; detecting interference between wireless communication devices; RSSI (received signal strength indicator) And transmit power level detection; performance evaluation of step attenuator; measure amplifier gain and network attenuation; measure forward power and reflected power in directional coupler; measure GSM signal strength modulated by GMSK