Explore the WSPR-zero Project

Explore the World of Digital Radio with WSPR-zero

WSPR-zero is an open-source hardware and software project designed to enhance your experience with the Raspberry Pi Zero by turning it into a powerful radio transmitter capable of sending and receiving WSPR signals. This project is crafted to be accessible for enthusiasts of all technical levels, from beginners to advanced users.

Raspberry Pi WSPR Hat Low Cost & Easy Setup


Easy Setup!

WSPR-zero’s super easy setup requires no SSH or other complicated Linux tasks. Simply use the friendly Raspberry Pi Imager tool to write the WSPR-zero image to an SD card, boot your Pi and then visit the WSPR-zero Configuration page to set your call sign and other options.

Low Cost

Designed to maximize your budget, the WSPR-zero transmitter is an affordable solution that leverages the Raspberry Pi Zero’s capabilities without the need for expensive peripherals. For under $80 you can build your own WSPR-zero!


Lightweight and compact, this transmitter hat is ideal for on-the-go applications, easily fitting into small spaces, perfect for backpacking and travel adventures.

What is WSPR?

WSPR, or Weak Signal Propagation Reporter, is a digital radio protocol designed to test radio wave propagation across the globe. By utilizing low-power shortwave signals, WSPR examines how these signals travel by bouncing off the ionosphere, providing insights into atmospheric conditions, radio wave behavior and antenna design. This protocol is especially significant for its ability to transmit very weak signals across vast distances, making it a robust tool for radio enthusiasts and researchers alike.


The unique characteristics of WSPR include its precise transmission length of 110.6 seconds, which optimizes error tolerance by transmitting at a very slow data rate. This meticulous timing, coupled with a 9.4-second buffer period, prevents overlapping transmissions and facilitates a seamless switch between transmit and receive modes. Each transmission, containing just 40.5 bytes of data, contributes to a vast global database, offering a rich resource for analysis and contributing to the collective understanding of global signal propagation.

WSPR Transmission Facts

WSPR takes advantage of very low baud speed and high error tolerance to accurately transmit just enough data to meet the goals of radio wave propagation testing and research.

Transmission Duration (s)

Low Data Rate! (baud)

Date Size (bytes)

Ultra Portable WSPR Rig!

Ultra portable WSPR-zero

The compact as the WSPR-zero is the perfect side quest for backpacking and road trips.

WSPR-zero in John Muir Country

Previous generation of WSPR-zero using the TAPR.org low pass filter transmitter board. Note the GPS module to help keep the time in sync since WSPR is so dependent on accurate time.

Join the WSPR-zero Community