It's because radar puts out radiation (RF, EMF is radiation). They close a corridor for all tests like that. I don't follow space fence, but it is likely some radar or another out there.
Unless the plane gets painted directly with a very high powered radar, there isn't much risk, but there is always some concern with overlapping communication frequencies or hardware. It's just a prudent caution rather than some major risk.
I can see from the warning that it is very specific to close range and orientation to the runway. That tells me they have something emitting along that path and probably not something too powerful, but up close could be hazardous.
Unless the plane gets painted directly with a very high powered radar, there isn't much risk, but there is always some concern with overlapping communication frequencies or hardware. It's just a prudent caution rather than some major risk.
I can see from the warning that it is very specific to close range and orientation to the runway. That tells me they have something emitting along that path and probably not something too powerful, but up close could be hazardous.
