Specification: Transmission frequency can be set from within the range of 87 ~ 108MHz 15W high-low power adjustable, transmission distance of 3-4 km (1.9-2.5 mi) in the open air Designed with advanced modulation system and built-in PLL frequency, audio pre-emphasis, limiter, and low-pass filter circuit. Good heat dissipation: using high-quality dual ball bearing fan, reasonable heat dissipation channels, excellent thermal performance PC control: connect your computer via micro USB interface, plus supporting intelligent broadcasting software, to achieve diversification unattended broadcast. (time switch, time to play the specified music, etc) 1/4 wavelength of strong magnetic sucker antenna, can be tightly adsorbed on the car roof or any metal flat objects, easy to move the antenna to the outside, the roof, balcony or window, more effective transmission and reception of electromagnetic waves!Usage Scenario: Campus radio, supermarkets, churches, farms, factories notice, education and training, scenic broadcasting, corporate meetings, automobile cinema, outdoor team contact (received through the car FM radio) or create your own radio station.Specification:FM Transmitter Frequency Range:FM:87~108MHz Frequency Step:100Khz Frequency Stability:±10PPM Harmonics, noise radiation:≤- 50dB Output Impedance:50Ω RF output power:15W Audio Distortion:0.3% Bluetooth distance:about 5m Frequency Response:50Hz~15000Hz Separation:≥30dB Input Level:≤-15 ~15dBV Frequency Modulation:±75KHZ SNR:≥60 dB Antenna Connector Type:TNC Operating Temperature:-10°C~45°C Color:Silver Transmitter Size:144 x 100 x 59mm Transmitter Weight:535 gAntenna Connector Type:TNC Gain:2.15dB Impedance:50Ω Maximum output power:20W Maximum stretch length:1150mm (3.77 ft) Shortest contraction length:210mm(0.69 ft)