substandard propagation

substandard propagation

[¦səb′stan·dərd ‚präp·ə′gā·shən]
(electromagnetism)
The propagation of radio energy under conditions of substandard refraction in the atmosphere; that is, refraction by an atmosphere or section of the atmosphere in which the index of refraction decreases with height at a rate of less than 12 N units (unit of index of refraction) per 1000 feet (304.8 meters).