The KH3939 from Beijing KeHuan Century EMC Technology is a RF Spectrum Analyzer with Frequency 9 kHz to 300 MHz, Frequency Resolution 30 Hz to 10 kHz, Attenuation Range 0 to 35 dB, Spurious 40 dB(Response), AC Supply 220 VAC. Tags: Analyzer with Screen, USB / Computer Controlled. More details for KH3939 can be seen below.