WSPR: An Overview

WSPR, or Weak Signal Propagation Reporter, is a digital communication protocol designed to facilitate the study of low-power, long-distance radio wave propagation. Developed by Joe Taylor, K1JT, a Nobel Prize-winning physicist and radio amateur, WSPR is built upon the principles of using minimal resources to achieve maximum efficiency in radio communication. It is primarily used by amateur radio operators, researchers, and enthusiasts to study radio wave behavior and to assess the performance of radio equipment and antennas.

Technical Aspects

WSPR is a unique communication mode that uses very low power transmissions, typically ranging from milliwatts to a few watts. It employs a highly efficient modulation scheme, a form of frequency shift keying (FSK), and advanced digital signal processing techniques to enable the detection and decoding of weak signals. WSPR signals consist of a sequence of precisely timed and frequency-shifted tones that convey information about the transmitting station’s call sign, grid locator, and output power.

The WSPR protocol operates within specific amateur radio frequency bands, typically between 1.8 MHz and 144 MHz, with an allocated bandwidth of 200 Hz. The system’s inherent narrow bandwidth and slow data rate (1.4648 baud) make it well-suited for low-power transmissions over long distances. WSPR transmissions occur in two-minute intervals, with each transmission lasting approximately 110.6 seconds, followed by a 49.4-second silent period for receiving and decoding.

WSPR Software and Hardware

To get started with WSPR, users need access to appropriate software and hardware. WSPR software is available for various platforms, including Windows, macOS, and Linux, with the most popular implementation being the open-source WSJT-X software suite developed by Joe Taylor and his team. WSJT-X includes multiple digital communication modes, with WSPR being one of them.

In terms of hardware, users need a suitable radio transceiver capable of generating and receiving WSPR signals, along with a computer or device to run the WSPR software. Many modern software-defined radios (SDRs) and some traditional transceivers support WSPR directly or via third-party software. For those looking for a more compact and dedicated solution, several standalone WSPR transmitters and receivers are available, specifically designed for WSPR operation.

WSPRnet and Global Collaboration

The WSPR community actively collaborates and shares data through the WSPRnet (WSPR Network) platform. WSPRnet is a centralized database that collects and displays real-time propagation reports from WSPR stations worldwide. Users can access the WSPRnet website to view propagation maps, spot tables, and statistics related to WSPR activities.

By analyzing the data gathered from thousands of WSPR stations, researchers and radio enthusiasts can gain valuable insights into the factors affecting radio wave propagation, such as the time of day, solar activity, ionospheric conditions, and geographical location. This information can help optimize radio communication systems, develop more efficient antennas, and improve the understanding of the Earth’s ionosphere.


WSPR is a powerful and versatile tool for investigating radio wave propagation and assessing radio equipment performance. Its low-power and long-distance capabilities make it an ideal platform for amateur radio operators, researchers, and enthusiasts to study radio wave behavior and share their findings through a global network. By utilizing advanced digital signal processing techniques and fostering collaboration among users, WSPR continues to contribute significantly to the advancement of radio science and technology.