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Amateur Radio Enthusiasts Investigate Radio Waves During Solar Eclipses

In the world of amateur radio, Todd Baker, also known as W1TOD, stands out with a towering antenna structure in his backyard. This industrial conveyor belt salesman from Indiana has a passion for communication, connecting with fellow enthusiasts worldwide. Now, he’s turning his radio skills to celestial citizen science.

Starry Hobbies and Beyond

Todd Baker’s substantial backyard antenna collection, reaching up to 30 meters (100 feet) in height, hints at his intriguing hobby. With a call-sign that uniquely identifies him as an amateur radio operator, W1TOD is a member of the vibrant ham radio community, where individuals experiment with various radio systems. For Baker, “communications were just plain-o cool.”

Over the years, Baker has delved into different radio systems, including citizens band (CB) radio. He recalls the fascination he felt for these modes of communication and how they drew him into their world.

Today, Baker has added celestial citizen science to his repertoire. On October 14th and again in April, he and hundreds of other amateur radio enthusiasts will deliberately fill the airwaves during solar eclipses, as these celestial events sweep across the Americas. Their goal? To participate in a colossal experiment aimed at monitoring how solar eclipses impact radio transmissions.

The Skywave Effect

In Todd Baker’s 7.25-acre plot, adorned with antennae that point in various directions, he can make radio transmissions across the US and even beyond. With his equipment, Baker has transmitted his voice to the other side of the world, engaging in conversations with fellow amateur radio enthusiasts in Europe, New Zealand, and beyond. His equipment can accomplish this thanks to a phenomenon known as the “skywave effect.”

One of the antennae in Baker’s garden is specially angled to transmit a radio signal that initially stays close to the ground. Eventually, this signal reaches the ionosphere, a region of Earth’s atmosphere that starts around 80 kilometers (50 miles) above the surface and extends up to 650 kilometers (400 miles). When the radio signal encounters the ionosphere, it “bounces” off it, allowing radio operators to communicate over vast distances. This phenomenon is the foundation of long-distance radio broadcasts.

In essence, the curvature of the Earth becomes surmountable, as radio transmissions zigzag up and down between the ground and the ionosphere. This interaction allows radio waves, in the form of electromagnetic signals, to literally touch the sky during long-distance broadcasts.

The Enigmatic Ionosphere

What makes this phenomenon fascinating is that the ionosphere is far from stable, and scientists are still working to fully comprehend its intricacies. This atmospheric layer fluctuates, moves, expands, contracts, and is anything but uniform. Sometimes, it’s teeming with its own waves, akin to ripples on a pond, especially during sunrise and sunset.

The ionosphere’s behavior is influenced by the presence or absence of sunlight. During the day, sunlight ionizes atmospheric gases, producing electrons and causing the ionosphere to thicken. At night, with reduced collisions, the ionosphere’s lower layer diminishes. This nighttime thinning allows radio waves to travel farther, reaching higher altitudes before bouncing back toward Earth. It’s the reason people have long been able to pick up distant radio stations in the early hours of the morning.

Eclipses as Natural Laboratories

Understanding the mysteries of the ionosphere requires large-scale investigations, and eclipses provide the perfect opportunity to study its fluctuations. Eclipses are unique because they allow scientists to observe the ionosphere during daylight hours when most other celestial events affecting it occur at night.

Enter the amateur “ham” radio community, whose members are part of a citizen science collective known as HamSCI. As the two upcoming American eclipses approach, hundreds of volunteers will begin broadcasting during these events. Their goal is to track their experiences and share them with scientists. Todd Baker is among these volunteers, eager to contribute to the experiment.

Pioneering the Experiment

Leading this grand experiment is Nathaniel Frissell, a space physicist and electrical engineer at the University of Scranton in Pennsylvania, who founded HamSCI. He explains that there’s still much to learn about the ionosphere. Using an animation, he highlights the complexity of the ionosphere, emphasizing that its real-life behavior is far from the smooth, idealized representations in models. Scientists often struggle to predict its transient variations accurately.

During the upcoming eclipses, Frissell, known by his call-sign W2NAF, will collect data from various sources, including individual ham radio operators, volunteers using highly sensitive transmitting equipment during the events, and online databases tracking public radio activity. This collaborative effort is essential because standard academic instrumentation alone cannot cover the wide areas required for this experiment.

This endeavor follows a similar effort during a total solar eclipse over the US in 2017, in which Todd Baker also participated. He fondly remembers his picture in the local newspaper from that event.

The Importance of Ionospheric Research

Understanding the dynamics of the ionosphere is not merely an academic pursuit; it has practical implications. During military or disaster response operations, precise radio communications can be a matter of life and death. Radio operators need to know how to optimize their transmissions for successful broadcasts. Moreover, ionospheric variations can affect satellites. Solar flares, for example, cause the ionosphere to expand, increasing drag on satellites in orbit, necessitating adjustments to their altitudes.

Amateur Radio’s Role in Discovery

Radio enthusiasts like Todd Baker play a crucial role in these experiments, acting as a massive “distributed receiver.” As radio equipment advances, each experiment opens doors to finer discoveries about ionospheric variations. The unexpected and often unpredictable behavior of the ionosphere during eclipses continues to intrigue scientists like Ruth Bamford of RAL Space, UK.

In 1999, during a rare total solar eclipse in the UK, volunteers tracked variations in signal strength, revealing how radio transmissions could travel much farther than usual during an eclipse. With our incomplete understanding of the ionosphere, the upcoming eclipses hold the promise of more surprises.

The Spirit of Amateur Radio

While ham radio may be experiencing declines in some parts of the world, enthusiasts like Todd Baker remain committed to the hobby’s adventure and unpredictability. For Baker, these experiments promise to improve his ability to make successful broadcasts at specific times of the day, a skill many ham radio operators are eager to hone.

The allure of amateur radio extends beyond scheduled communication. It offers an element of surprise and serendipity that can’t be replicated through smartphone apps. Amateur radio enthusiasts liken it to navigating an ocean, requiring an understanding of nature’s forces, weather, and atmospheric turbulence to reach their destinations.

For Michelle Thompson, whose call-sign is W5NYV, it’s the unscheduled, opportunistic communication that makes ham radio truly special. Through her broadcasts, she’s made friends worldwide and even presented research at conferences. Amateur radio, she explains, isn’t just about talking to known contacts; it’s an ongoing adventure that keeps operators engaged in the unpredictable world of radio waves.

As amateur radio operators prepare to explore the ionosphere during the upcoming solar eclipses, they embrace the excitement of venturing into the unknown, where each transmission could lead to a serendipitous connection with someone across the globe.