WSPR, or Weak Signal Propagation Reporter, is a digital communication protocol designed for amateur radio operators. It allows users to transmit and receive low-power signals over long distances, making it useful for studying radio wave propagation. WSPR operates on various amateur radio bands and can automatically report signal reception to a central database. The system works by sending short, structured messages that include the transmitter's call sign, location, and signal strength. This data helps users understand how radio waves travel under different conditions, contributing to the broader field of radio propagation research.