Written by Professor Rob Rowlands, of Sonoma State University
(A final version of this article, can be found here: globehttps://ee.sonoma.edu/articles/2026/sonoma-state-engineering-students-launch-solar-powered-balloon-circles-globe )
This Spring semester, two accomplished instructors in the Engineering Department at Sonoma State University, Professor Rob Rowlands and Professor Robert (Bob) Salter, guided students in the E444L Radio Frequency Laboratory course to successfully launch the department’s first solar-powered high-altitude balloon on April 8th, 2026. The non-permeable Pico balloon was kindly provided by Martin Rothfield. The lightweight system, powered by small solar cells, carries a low-power radio transmitter that continuously transmits position and telemetry data, allowing it to be tracked globally using weak-signal propagation (WSPR) techniques.
Since launch, students have been actively monitoring the balloon as it now circumnavigates the globe a 2nd time. The balloon is currently above Japan on Monday evening (May 4th, 2026), approaching the Pacific Ocean for the second time. The solar-powered transmitter sends telemetry at 10-minute intervals, providing almost continuous real-time data and an exceptional hands-on learning experience in RF communication and atmospheric propagation. Reflecting on the project, Professor Rowlands noted, “This is a great experience for engineering students to see real-world RF communication, propagation, and tracking in action beyond the classroom.”
A geopolitical wrinkle is the absence of tracking information over the Middle East and China as GPS signals are regularly “spoofed” in conflict zones.
Cole Montano, a senior engineering student participating in the course, added, “Being able to track something we launched ourselves and watch it travel around the world is incredibly rewarding. It really connects theory to practice in a meaningful way.” Another student, Jose Alavez Marin, shared, “This project gave me hands-on experience with RF systems and showed me how concepts we learn in class apply to real-world engineering challenges.”
The balloon can continue to be tracked several ways, eg wsprnet.org, https://wspr.rocks/ etc. The callsign is NJ6Z, and be aware of whether the sun is likely to be shining at its current location, and thus powering the radio.
Above is the last contact location today 4 May 2026 at 0844 GMT, 0144 PST. It could well be aloft for several more weeks!
Subsequently on Wednesday April 28, 2026 the class prepared a latex “HAB” balloon for a “pop and drop” launch. This differs from the previous Pico balloon as the flight time may only be hours as the balloon climbs to altitude and explodes!
Students soldered the solar panels, dumped an entire party balloon tank of Helium into the balloon, and fashioned the 34 ft vertical dipole antenna with a WSPR transmitter at the center point. They launched the balloon and its radio at 215pm from the Salazar quadrangle. Unlike the earlier shallow launch path, this balloon went almost straight up, and we tracked its course around Sonoma and Marin Counties until it lost solar power about 6pm somewhere over Point Reyes.
An interesting anecdote to this second launch is that the bottom half of the dipole didn’t survive the launch, yet we continued to receive adequate signal at the Pt Reyes software defined radio (SDR)https://www.radiomarine.org/kph-sdrs. An unexpected benefit of this was the polar pattern of the antenna was no longer that of a horizontal doughnut, but more omnidirectional, allowing stations directly below the balloon to receive it. The previous Pico balloon could only be received at distances 1000km and beyond.
Congratulations to Professors Rowlands and Salter, and to the entire student team, on this outstanding achievement.