Artist’s rendering of Voyager traveling through space. (Image Credit: NASA/JPL-Caltech)
In late 2024, skilled radio amateurs with CAMRAS used the Dwingeloo Observatory to detect the carrier signal of Voyager 1 from over 15.5 billion miles away. To pick up the signal, they added more equipment to the dish and made adjustments to remove noise. The team originally detected the space probe in 2006, when it was 9.1 billion miles from Earth. It’s very difficult for astronomers to detect Voyager 1’s signal without relying on NASA’s equipment. Only elite detectors, such as VLBA arrays and the Green Bank Telescope, have achieved it in the past.
For their discovery, the CAMRAS team leveraged the observatory’s 25-meter dish. They installed a custom high-frequency feed to handle 8.4 GHz at the telescope’s focus. Adding this turned out to be the right choice as the wire mesh-based dish (optimized for lower frequencies) reflects those waves inefficiently without it.
Afterward, they performed pre-observation tuning. The team precisely modeled Voyager’s trajectory using JPL ephemerides (orbital data) and simulated the expected frequency drift over the ~15.5-billion-mile path, adjusting the receiver beforehand. These predictions were used to predict and correct the Doppler shift caused by their relative motion. Making this adjustment in real-time allowed the live carrier signal to emerge from noise during observations.
Carrier peak emerging from noise floor. (Image Credit: Radio Telescope Dwingaloo/CAMRAS)
The receiver chain details involve cryogenically cooling a low-noise amplifier (LNA) chain to drastically reduce thermal noise. A spectrum analyzer was also used for visualizing the carrier peak ascending from the noise floor in real time. Pulling the very faint signal (10-16 W/m2) from background noise required approximately two hours of integration per session, cryogenic low-noise amplifiers, and post-processing verification via the telltale Doppler wiggle and spectrograms.
Astronomy enthusiasts can’t use home equipment like big amateur dishes or software-based radios without DSN-scale gear to pick up Voyager 1’s signal. After all the traveling, it becomes very weak by the time it reaches Earth. The probe transmits 22W via its 3.7-meter dish antenna at 8.4 GHz, over 15.5 billion miles. When it arrives to Earth, the signal drops down to ~10-16 watts per m2, trillions of times weaker than a cell phone signal. Some demos used linked global arrays like VLBA or the Green Bank Telescope. Even then, the carrier tone is theoretically audible with elite radio astronomy tools.
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