Measures for Progress: A History of the National Bureau of Standards

POLICING THE ETHER 291
If simple restriction on their proliferation, as the obvious solution to
station interference, impinged on free enterprise, a degree of order seemed
possible if the stations would operate exclusively on the frequency assigned
to them, use as small power as was required to reach the necessary distance,
and use waves as sharp as possible. The first two remedies were outside
the realm of the Bureau, and it therefore concentrated on the measurement
and control of the radio waves emanating from the stations, since the fluc-
tuations in their width determined their capacity for interference.205 Typi-
cal was the experience of a listener in Baltimore who reported interference
between two broadcasting stations, one in Cincinnati, the other in California.
The interference arose, the Bureau learned, because one of the stations was
off its assigned frequency by one-half percent.
Bureau development of new and improved types of wavemeters,
wavemeter scales, and devices for rapid radiofrequency measurements gave
the Radio Inspection Service of Commerce better instruments for detecting
and monitoring broadcasting frequencies.206 Then in 1923, in order to pro-
vide means of self-policing, by enabling broadcasting and other stations to
hold exactly to their assigned frequencies, the Bureau set up a standard of
frequency and began sending out precise signals over its laboratory trans-
mitter, WWV, set up at Beltsville, Md. The frequency signals were trans-
mitted in groups each day so that the range from 125 to 6000 kilocycles was
covered every 2 weeks for all stations within range of the Bureau signal.
The obvious advantage of the service soon led to more frequent transmission
of the signals and to their broadcast over a nationwide system of standard
frequency stations.207
Holding to an assigned frequency was not always enough in the noisy
crowded air at that time. In January 1924 when the dirigible Shenandoah
tore loose from her mast at Lakehurst during a winter storm and with only a
skeleton crew aboard was lost for almost 20 hours, all New York broadcast-
ing stations went off the air to keep from interfering with her messages.208
An enormous improvement on the original frequency standard—a
tuning fork device—was the piezo oscillator which used a quartz plate
vibrating at a radio frequency.200 As modified by the Bureau, it furnished an
202 NBS Annual Report 1923, pp. 64—65.
Dellinger, "The Bureau of Standards lends a hand," Radio Broadcast, 2, 40 (1922).
207 Letter, Acting Director, NBS, to Department of Electrical Engineering, Pennsylvania
State College, Jan. 26, 1923 (NBS Box 46, JEW); NBS Annual Report 1923, pp. 66—69;
Southworth,. Forty Years of Radio Research, p. 40; LC171 (1925), superseded by
LC280 (1930).
John Toland, Ships in the Sky, p. 85.
209 The piezo or pressure electricity effect on quartz was first identified by Pierre Curie in
1880. Its application to radio stations was described in LC223, "Use of piezo oscillators"
(1927).