Achievement in radio

From Mechanical Objectivity to Instrumentalizing Theory: Inventing Radio Ionospheric Sounders

“…He also calculated their averages to follow their diurnal and seasonal variations. 68 The automatic multi-frequency recorder was much faster than manual frequency scanning. Gilliland's instrument took nine and a half minutes to generate a complete ionogram for frequencies from 2.5 MHz to 4.4 MHz with an almost contiguous frequency change (i.e., a rather high frequency resolution).…”

Space Weather Effects on Technologies

“…Because wireless remained the only method for cross-oceanic voice communications for more than five decades following Marconi's feat, physical changes in the radio wave-reflecting layer (even before it was "discovered") were critical to the success (or failure) of reliable transmissions. (An excellent chronology and summary of events in the history of wireless from 1819 to 1976 is provided in the first chapter of Snyder and Bragaw [1986].) The same ionosphere electrical currents that could pro duce "spontaneous" electrical currents within the Earth could also affect the reception and fidelity of the transmit ted long-distance wireless signals.…”

Primary atomic frequency standards at NIST

“…This paper describes NBS/NIST work on three classes of atomic frequency standards: cesium-beam frequency standards, cesium-fountain frequency standards, and stored-ion frequency standards. No effort has been made to provide a comprehensive institutional history of this work, since the early part of this history is well covered in papers by Beehler [ 6 ] and Ramsey [ 7 ] and in books by Snyder and Bragaw [ 8 ] and Passaglia [ 9 ].…”