Spectrum Coordination Act This bill requires the National Telecommunications and Information Administration and the Federal Communications Commission to update the Memorandum of Understanding (MOU) on Spectrum Coordination to (1) improve the process for resolving frequency allocation disputes in shared or adjacent spectrum bands, and (2) ensure the efficient use or sharing of spectrum. The MOU formalizes the cooperative relationship between the two parties to ensure that spectrum policy decisions promote efficient use of spectrum consistent with both the economic interests and national security of the nation.