. Some quantitative experiments in long-distance radiotelegraphy . 100 200 300 400 500 600 700 80Q 900 1000 MILESFig. 3 are represented by crosses. Observations taken by the deflectionmethod are indicated by circles around the crosses, while nightobservations are accompanied by the letter N. It is seen that theday observations correspond approximately to the values of thecalculated cinve, but that the night signals are entirely irregular, 330 Bulletin of the Bureau of Standards [ No. 3 being in general stronger than the day signals, as was first observedby Marconi. Sometimes they lie clo
. Some quantitative experiments in long-distance radiotelegraphy . 100 200 300 400 500 600 700 80Q 900 1000 MILESFig. 3 are represented by crosses. Observations taken by the deflectionmethod are indicated by circles around the crosses, while nightobservations are accompanied by the letter N. It is seen that theday observations correspond approximately to the values of thecalculated cinve, but that the night signals are entirely irregular, 330 Bulletin of the Bureau of Standards [ No. 3 being in general stronger than the day signals, as was first observedby Marconi. Sometimes they lie close to the K/d curve, indicatingthat the absorption has disappeared, while at others they arepractically of the same strength as the day readings. In a veryfew cases, night signals were observed considerably stronger thanthe calculated value for zero absorption, but these may very Ir 10-6AMP. 700 600 500 400 300 200 100 BIRMINGHAM RECEIVED AT BRANT ROCK, JULY, 1910. 00 200 300 400 500 600 700 800 900 1000 MILESFig. 4 probably be due to errors of observation, since it is not observedthat the remarkable strength of signal is reciprocal between thetwo stations. If the observations are genuine, however, it wouldperhaps indicate some kind of reflection from the upper layers ofthe atmosphere. Austin] Experiments in Long-Distance Radiotelegraph)/ THE CAUSE OF THE ABSORPTION 331 According to the calculations of Zenneck/® the conductivity ofair at moderate heights can not explain the magnitude of theobserved absorption, neither can the sea-water absorption be of lO^ AMP. 700 600 500 400 300 200 100 BRANT ROCK RECEIVED ON BIRMINGHAM, JULY, 1910 Is=56 AMP. X=1500 DAY OBSERVATIONS X NIGHT 1 \ \\ \ \ \\\\ < \ -) % N,X • \ 1 V N X N x ^^^ MM X X X . 100 200 300 ADO 500 600DISTANCEFig. 5 700 800 900 1000 MILES the proper magnitude, according to the same author. But as thewave front at any considerable distance from the sen
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