Methods for locating noise in a CATV system are disclosed. The methods may use a probe or instrument configured to be coupled to a port of the CATV system. The probe may be operable to selectively filter signals in the CATV system to suppress the frequencies at which noise may be present in the CATV system. In some embodiments, the methods may also use a signal level meter, and the probe may be configured to be coupled to the signal level meter to detect and locate noise in the CATV system.