Despite RCA's plunge at the New York World's Fair in the spring of 1939, the FCC proceeded cautiously before setting signal standards for the U.S. television industry.
The National Television System Committee (NTSC) was formed in March 1940, and did not deliver a set of standards until March, 1941.
When the NTSC standards were finally settled, they adopted a standard 20% sharper than what RCA was using, which sent the company back to the drawing boards.