(Credit: AST SpaceMobile)
Facing thousands of complaints, AST SpaceMobile is pushing back against concerns that the company’s giant satellites risk interfering with amateur “ham” radio operations across the globe.
On Tuesday, the company sent a letter to the US Federal Communications Commission, defending its plan to use the 430 to 440MHz radio bands outside the US to track and control its proposed fleet of 248 satellites.
Those bands have long been allocated to amateur radio operations, including for emergency communications, so the community has been campaigning to stop AST from gaining access. It flooded the FCC's online system with over 2,500 comments, many of them protesting AST’s plan to use the spectrum.
AST SpaceMobile finally responded by telling the FCC that it has designed its satellites to "mitigate interference" with amateur radio bands.
In addition, the company says it’s proposing "very limited, non-routine" use of the 430 to 440MHz bands and only for launch and early orbit phases for its satellites or "emergency operations when other frequency bands are unavailable." AST also says it can shut down radio band use if interference is detected.
In addition, the company has submitted an analysis from a third-party company, RKF Engineering Solutions, which found the risk of interference to amateur radio operators to be “extremely unlikely.”
“Modeling shows that even under worst-case conditions, the probability of interference with amateur satellite service is extremely small—less than 0.1% per pass, and only a handful of events were observed in a 30‑day simulation,” the analysis says.
(Credit: AST SpaceMobile)AST is urging the FCC to greenlight its plan to launch and operate commercial services over its 248-satellite constellation, which is designed to beam connectivity to everyday smartphones. The resulting system will compete with SpaceX's cellular Starlink service, which is already available through T-Mobile.
However, the amateur radio community has been calling on the FCC to deny AST's push to use the 430 to 440MHz bands. On Tuesday, the American Radio Relay League sent its own letter to the Commission, highlighting the stiff opposition across the amateur radio community to the spectrum use. “At least 17 national radio amateur societies from around the world took the extraordinary step of making their opposition known to the Commission,” the letter says.
Some of the amateur radio groups also claim to have detected interference in Europe from AST’s fleet of existing satellites, the first five BlueBirds and the BlueWalker 3. “Unlike many commercial services, amateur radio is often the only communication system still operational during natural disasters and emergencies,” the Bulgarian Federation of Radio Amateurs told the FCC.
In its letter to the FCC, AST said: “Despite contrary claims from some amateur radio commenters, AST SpaceMobile is not transmitting in the 430-440 MHz band on the BB1s or BW3.” Still, one amateur radio group has detected evidence that AST merely shut down the radio communications from the BlueWalker-3 satellite two weeks ago.