Easier Cable Field Testing with Field Fox

Keysight Technologies

Easier Cable Field Testing with FieldFox

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Easier Cable Field Testing with FieldFox

Keysight Technologies Inc.

Santa Rosa, Calif.

Engineers and technicians typically experience multiple cable testing challenges in the field. Meeting these challenges head on, Keysight Technologies recently introduced two innovative measurement options that make their FieldFox handheld analyzers the industry’s most comprehensive and effective cable test solutions in the industry.

Cable Test Challenges

Cables (e.g., waveguide, coaxial and twisted pair) are by far the most widely used components in modern RF and microwave systems such as wireless and data communications, satellite communications and radar. They are also the leading cause of failure in these types of systems. That’s why proper maintenance and using the right tool for testing in the field is so critical.

The typical cable test process starts by determining whether or not a cable is faulty or performing outside its desired specification. If so, the fault’s physical location along the cable must be found. Once the location is determined, the next step is to understand the nature of the error and repair it. During troubleshooting and maintenance, engineers and technicians can identify a fault’s location with return loss (RL) and distance-to-fault (DTF) methods, but they are unable to determine the cause or type of fault. This makes it difficult to repair. In many cases, the failures (e.g., loose or damaged connectors, water ingress or broken solder joints) can’t be seen by just looking at the cable.

Another problem is that measuring cable performance has traditionally required engineers and technicians to transport a cable and antenna analyzer, network analyzer, signal generator and power meter into the field. That process is all the more complicated when the cables are used in systems located in hard to reach or even potentially hazardous environments. Once in place, the instruments must be correctly set up for testing. While effective, the process is error prone and leaves the instruments subject to accidental damage.

Further complicating matters, traditional vector network analyzers (VNA) have difficulty making precise and repeatable high-loss measurements for in-situ microwave cables where test ports are long distances apart.

NEW Cable Measurements options

FieldFox’s new Time Domain Reflectometry (TDR) cable measurement option (Option 215) complements the analyzer’s current RL and DTF measurements. The RL measurement capability exposes cable connection mismatch, while the DTF capability indicates the location of any faults or poor connections along the cable. The new TDR option provides engineers with new insight to help measure the impedance changes along the cable and identify the cause (type) of specific faults, such as short, open or water ingress. To date, FieldFox is the only handheld analyzer that can perform RL, DTF and TDR measurements with the same instrument in a single sweep.

FieldFox’s TDR, or step measurement, captures data using the same process as DTF. However, unlike DTF, the measurement is used to characterize the type of fault, including inductive or capacitive discontinuities. It does so by observing reflected waveforms from a step propagating through a cable. By analyzing the duration, magnitude and shape of the reflections, the nature of the impedance variation in the cable can be determined.