Section V. MAINTENANCE

MAINTENANCE

5.1 Periodic Checking

The RF Voltmeter is designed to give long periods of service

without maintenance when operated in accordance with these

instructions.

It is recommended, however, that the instrument

be checked occasionally using reliable standards to insure

against errors resulting from deterioration of tubes or chopper.

To make these checks, it is necessary to have a signal source

in the 200 to 500 Kc region with less than 2% distortion at

A precision electronic volt-

levels up to 3 Volts across

meter of the averaging response type, such as the Ballantine

Model 310A or 314, Hewlett Packard Model 400D or 400H, may be

used to monitor the signal source for this purpose. To insure

its accuracy, the monitoring meter should be checked at some

low frequency (50-100 cycles) of good waveform against a

dynamometer type AC meter of at least 1% accuracy.

5.2 Calibration Precautions

When attempting to check the voltage calibration accuracy on

art instrument having the sensitivity and bandwidth of this

RF Voltmeter, it is essential to take precautions to avoid

errors resulting from stray pick-up voltages.

3.4c,d). A well shielded signal source must be used in con-

junction with coaxial connections to both the RF Voltmeter

and the standard referenced meter. Even with a well shielded

generator and associated connections, it is sometimes possible

for the reference meter to pick up stray RF signals and feed

them into the probe. Check for this condition by disconnecting

the standard meter and noting change in level.

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