The Measurement of Radio-Frequency Power

The possibilities of the cathode-ray wattmeter have been investigated between sixty cycles and forty megacycles. Its use can be extended to between 100 and 200 kilocycles by the use of either selective or nonselective amplifiers, thus permitting a wide range of power sensitivity. When the nonselective amplifier is used or when no amplifiers at all are used, the power measured includes all the harmonics; when the selective amplifier is used, the power is limited to the power on that frequency to which the amplifiers are tuned. The wattmeter has been extended by the use of a suitable pickup mechanism and suitable selective amplifiers to forty megacycles. For some purposes it is an indispensable instrument and for others a very useful instrument permitting more rapid, if not as accurate, measurements than are possible with other methods.