Alexanderson Day 2026

July 5, 2026

Today I finally had the opportunity to visit Grimeton Radio Station (SAQ), a UNESCO World Heritage Site, during Alexanderson Day 2026. It has been on my list for a long time, so I was genuinely delighted to finally experience it in person.

Witnessing the 100-year-old, 200 kW Alexanderson alternator in operation was unforgettable.

The Alexanderson alternator (“The Old Lady”) in operation during Alexanderson Day 2026.

During the event, a live Morse message was transmitted at 17.2 kHz using the original alternator, demonstrating one of the earliest technologies for long-distance wireless communication.

The message welcomed listeners around the world and celebrated how radio continues to connect people across borders and generations, even a century after the Alexanderson alternator first entered service.

What makes Grimeton truly exceptional is that it is home to the world’s only operational Alexanderson alternator. Another surviving machine exists in the United States, but it is no longer operational, making each SAQ transmission an exceptionally rare opportunity to experience a remarkable piece of engineering history in action.

Standing beside these enormous machines, it was impossible not to admire the ingenuity, precision, and craftsmanship that made global wireless communication possible long before the digital age.

The engineers at Grimeton maintain much of the original equipment themselves. The Alexanderson alternator, affectionately known as “The Old Lady”, is irreplaceable. Its continued operation reflects their expertise, dedication and craftsmanship.