A Method of Measuring Very Short Radio Wave Lengths and Their Use in Frequency Standardization

The paper describes one method of establishing frequency standards employed by the Bureau of Standards which is based on the direct measurement, in linear measure, of the wave length of very short standing waves on a pair of parallel wires. The wave lengths measured were from 9 to 16 meters, the currents having frequencies from 33,000 to 19,000 kilocycles per second. The apparatus for generating these ultra radio-frequency currents is described, as well as the details of the method used in measuring the wave length of the waves which they produce on the parallel wires. A method is described for calibrating a wavemeter at frequencies from 30,000 kilocycles to 352 kilocycles (10 to 850 meters). This method makes use of the harmonics in a second radio-frequency generating set, one of which, when combined with the output from the ultra radio-frequency generating set, produces a beat note in a receiving set tuned to the ultra radio-frequency. The zero beat note method is used to obtain an exact setting. Knowing the frequency of the ultra radio-frequency generating set by direct measurement on the parallel wires, and the order of the different harmonics being used in the second radio-frequency generating set, the frequency of the latter may be determined over the range from 30,000 kilocycles to 352 kilocycles (10 to 850 meters).