We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
FIG. I
Standard wavemeter of the Bureau of Standards
Reducing the Guesswork in Tuning1
T
How the Bureau of Standards Will Measure the Wavelengths of Broadcasting Stations with an Accuracy of 99.9%, Making it Possible for Any One to Use His Receiving Set as a Wavemeter
By J. H. DELLINGER
Chief, Radio Laboratory, Bureau of Standards
HE good results already appearing from the recommendations of the Second National Radio Conference could easily be wrecked if the radio broadcasting stations and other stations should not operate accurately on the frequencies to which they are assigned. One of the reasons why interference has been the great draw-back to progress in radio has been that the transmitting stations have used waves which approximated the assigned wavelength or frequency only very roughly indeed. Among its numerous tasks of standardization and research, the Bureau of Standards has devoted itself with some vigor to the task of improving the frequency standards of the country, with the result that there is every prospect that the interference situation will be greatly relieved from now on. The Bureau's work in this direction2 has been directed at two objectives:
Published by permission of the Director, Bureau of Standards.
2Among those who are engaged in this important work, under Dr. Dellinger's direction, are Mr. E. L. Hall, the Misses F. Kenyon and G. Hazen, Mr. F. W. Dunmore, Mr. F. H. Engel, and Mr. H. J. Walls.
increasing the accuracy of its standards, and making these standards available to the radio public.
About a year ago the Bureau began a program of work which would materially improve the accuracy of its radio-frequency measurement. Prior to that time the basic wavemeter standards were based entirely on circuits made up of standard capacities and inductances, the values of which were either calculated or measured at low frequencies. These standards were prepared with great care and precautions were taken to avoid errors in the measurements, but there was no certainty that the frequency basis thus established could be relied upon to be correct within less than i per cent., particularly for the very high radio frequencies. The work that has been done recently has given a new basis of measurement, resulting from several interesting and quite independent methods of frequency determination, and is much more accurate. The goal set in this work was an accuracy of 99.9 per cent. The reason why this degree of accuracy is important may be seen from a brief consideration of the