Wow, pretty bold statement and I am not trying to be a dick or anything but the concept of FM was developed by maybe the greatest radio engineer ever Edwin Armstrong in 1933, the first commercial broadcasting station W2XMN went on the air in 1936 and Armstrong’s
early test with the New Jersey State police and FM radios so impressed the Signal Corps that they were early adopters of FM in military communications.
The SCR-522 is about as AM as they come, FM is so much better in military mobile communications that the rest of the world followed post war. Civil and Military aviation somehow missed the boat and struggled with AM forever. Or at least now is being replaced
by digital.
Googol Armstrong and do some studying!
Ray F/KA3EKH