Small hardware device for transmitting WSPR messages based on the SI5351 IC. Built-in TCXO to eliminate frequency drift, ensuring stable operation. Compatible with active antennas and features transmission time synchronization. Automatic QTH locator calculation for enhanced operational efficiency. Buffer amplifier based on a 74ACT244 IC for improved signal quality. This device is compact, measuring 50*20*63 mm (excluding connectors), and utilizes SMA RF connectors with a 50 Ohm coaxial cable feed line. It supports external active antennas and has a maximum output power of approximately 23 dBm. The supply voltage is USB-5V, and after configuring the call sign, grid, and frequency via the serial port, it can operate independently without external software or code. Color: Black Material: ABS Package Contents: 1 x Unit 1 x antenna 1 x Type-c cable