The report presents numerical results in the form of graphs of the power reflection coefficient for electromagnetic signals normally incident upon a plasma gradient. An electron collision frequency that is independent of position in the plasma interface is assumed. A 'slide rule' is provided to enable quick determination of the magnitude of the reflection coefficient for 'very overdense, exponential plasmas' in the lower atmosphere (to 70 km) for frequencies from 30 MHz to 10,000 MHz. For plasmas that only reach a finite density, a complete set of graphs is given presenting power-reflection coefficients for normalized plasma parameters. Reflectivities are plotted if greater than 10 to the -20th power. Normalized collision frequencies (Z) from 0.003 to 1000 are covered. Normalized plasma to RF frequency ratios inside the plasma cover the range from 0.01 to 100. Characteristic distances over which the plasma density exponentiates in the gradient region vary from 0.003 wavelengths to 1000 wavelengths. Simple aids to the reader are provided so that he may easily determine his parameters for use with the reflectivity curves, should his plasma be of atmospheric constituents.