Instruction manual

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4-2. Adjustment and Calibration
Regular adjustment and calibration of this instrument is recommended. The
procedures involved should be executed by qualified and authorized personnel only.
4-3. Cleaning and decontamination
The instrument can be cleaned with a soft clean cloth to remove any oil, grease
or grime. Never use liquid solvents or detergents. If the instrument gets wet for any
reason, dry it using low-pressure clean air at less than 25 PSI. Use care and caution
around the window cover areas where water could leak into the instrument while
drying.
5. OTHER
5-1. BNC Cable Considerations
The accuracy of radio frequency measurements can be affected by the
connections between the signal source and counter. The main issues involved are
standing waves and cable shunt capacitance.
Waves propagating along a transmission line will be reflected at its ends if the
line is not terminated in its characteristic impedance. These reflections will set up
standing waves in the line, which may cause damage to the signal source or
produce inaccurate measurements. This effect increases as the cable length
reaches one-fourth of the wavelength for the frequency being measured. Standing
waves can be minimized by keeping cable lengths short, or eliminated by providing
a proper termination. RG58 cable, for example, has a characteristic impedance of
50Ω. The proper termination for this cable would, therefore, be a 50Ω resistor
between the center conductor and the shield. A standard BNC, 50Ω cable
termination is most often used for this.
Input A has an input impedance of 1 MΩ shunted by < 40 pF. Radio frequency
measurements made at this input will experience standing waves and attenuation
due to the shunt capacitance of the cable which adds to the shunt capacitance at
the input. For RF measurements at input A, it is recommended that a 50Ω
termination be used, or that the cable be no longer than three feet (91 cm).