MMA working groups are now considering several issues concerning telescope and receiver design, and the virtues of single sideband (SSB) versus double sideband (DSB) receiver operation. We review here the relationships showing how receiver, atmospheric, and spillover noise affect the effective system temperature. We derive a few results relevant to the single sideband versus double sideband issue, and suggest a goal for the ultimate receiver performance in the presence of atmosphere and spillover losses. In the discussion of each noise and loss term, we present diagrams which characterize what we anticipate the system temperatures will be for a single MMA antenna operating in total power mode.