This paper presents a simple derivation of the probability distribution of the monopulse ratio. The derivation is based upon a conditional distribution and considers both Rayleigh targets and simple non-Rayleigh cases. The mean is obtained almost without calculation. The variance expression is given a completely general noise + glint interpretation. Analytical expressions for angle error mean and spread, including noise, target width and unresolved targets, are presented, as functions of antenna position, in simple and comprehensive diagrams.