Direct reading indicator type

An item for the determination of the electrical wavelength or frequency being generated by an electronic equipment such as a radio transmitter. It may be placed in the radiation field of the equipment, thereby operating on the "absorption" principle, or connected into a transmission line or waveguide run between the equipment and a component such as an antenna, thereby operating on the tuned cavity resonance principle. It includes inscriptions from which the wavelength or frequency can be determined directly, or by reference to an associated calibration curve or tabulation. The wavemeter operates in accordance with its design function only when the equipment under measurement is operating. For items, such as grid dip meters, that determine the same information when the equipment under measurement is not operating, see frequency meter.