Ramesy was a student if I.I. Rabi, a Columbia professor, who served as the director of the Radiation Lab at MIT during the war. The Rad Lab concerned itself with radar. It was at the Rad Lab that Ramsey learned microwave technique necessary for his inferometer. I am not sure exactly what role Ramsey played in the Manhattan project, but the bombs did use radar altimeters for fusing.
The Rad Lab had a bigger budget than the Manhattan Project. Radar won the war. The A-bomb ended it.