HF coaxial cable reflectometer tester - has tuneable oscillator in hand-held unit with standing-wave indicator with number of deflections indicating distance of fault

摘要

The coaxial cable tester is of the reflectometer type and is fully portable. The instrument is housed in a hand-held case with pistol-grip containing the batteries. A variable-frequency HF oscillator is tunable over the range 70 to 90 Mhz and is loosely coupled to the cable under test via coil and coaxial connector. The oscillator may be permeability-tuned or use varicap-diode tuning. The oscillator is tuned over its range by operating a trigger handle which also switches-on the circuit. Faults in the cable cause standing waves to be set up whose anodes can be indicated by deflections of a meter as the oscillator is swept over its range. Each deflection corresponds to a distance of approx. 5 meters between the measuring point and the fault position along the cable.