A TDR cannot detect small performance changes at RF frequencies, so it is not possible to monitor performance degradation between maintenance intervals with these traditional methods.
Without FDR techniques, the “Fix after Failure” philosophy becomes the only alternative.
The FDR measurement technique requires a swept frequency input to the transmission line.
An inverse FFT (Fast Fourier Transform) is performed on the reflected signals transforming this information into the time domain.
Preventative maintenance has another set of benefits even more important than cost. Overall quality is improved giving greater customer satisfaction.Eventually these problems cause intermittent outage and failures at exactly the times they are least welcome, such as during storms or during extreme periods of cold.With DTF available, the root causes of RF problems can be identified.For the majority of transmission lines and antennas, the absence of DTF capability severely impacts the time to repair transmission lines and renders preventative maintenance procedures impractical.RF failure conditions at the top of a tower or through a bulkhead frequently are not measurable with traditional tools such as TDR and spectrum analyzers with tracking generators.FDR is a transmission line fault isolation method which precisely identifies signal path degradation for coax and waveguide transmission lines.Although the acronyms are similar, FDR technology is different from traditional Time Domain Reflectometry (TDR) techniques.For example, connector corrosion can be detected early and weather seals replaced before moisture destroys expensive cables.DTF finds these problems because the FDR technique can accurately detect very small performance changes within the transmission line.These common problems can cause unwanted signal reflections.Poorly tightened connectors and poor environmental seals are exacerbated by acid rain corrosion.