In telecommunication, effective Earth radius is the radius of a hypothetical Earth for which the distance to the radio horizon, assuming rectilinear propagation, is the same as that for the actual Earth with an assumed uniform vertical gradient of atmospheric refractive index.
Note: For the standard atmosphere, the effective Earth radius is 4/3 that of the actual Earth radius.
... abbreviated DRM, is an umbrella term for any of several arrangements by which the usage of copyrighted data by someone who has purchased a copy of it may be restricted by ...