System and method for diagnosing RF signal strength at a set-top terminal

A system and method for diagnosing RF signal strength at a set-top terminal includes a network characterization diagnostic tool, such as a diagnostic application routine, that is loaded into the flash memory of the set-top terminal. An installation technician or field service engineer invokes the diagnostic application routine by entering a pseudo secret key sequence into the set-top terminal. Then, the diagnostic application routine measures the RF signal strength for the entire bandwidth and produces a visual display of a plot of the signal strengths on a television set operatively coupled to the set-top terminal. The display allows the installation technician or field service engineer to easily diagnose whether a "hole" or "tilt" exists in the measurement of the RF signal strength.