. Some quantitative experiments in long-distance radiotelegraphy . that strengthof signal which permits a clear differentiation of the dots anddashes. The Birmingham sailed from Provincetown early on the morn-ing of July 14, taking a course nearly south until she had attaineda distance of about 1200 miles from Brant Rock. The Salem ^ The actual amount of current in the antenna for the same intensity of signal in thedetector varies with the effective resistance, which in turn depends on the wave lengthand amount of tuning inductance. The energy in the detector, required to producegiven signals
. Some quantitative experiments in long-distance radiotelegraphy . that strengthof signal which permits a clear differentiation of the dots anddashes. The Birmingham sailed from Provincetown early on the morn-ing of July 14, taking a course nearly south until she had attaineda distance of about 1200 miles from Brant Rock. The Salem ^ The actual amount of current in the antenna for the same intensity of signal in thedetector varies with the effective resistance, which in turn depends on the wave lengthand amount of tuning inductance. The energy in the detector, required to producegiven signals is constant, however. This energy is what is actually measured in takingshunt readings, and for convenience of comparison its square root is put in terms ofmicro amperes through 25 ohms which was the resistance actually employed in thethermoelement readings at Brant Rock, and which is approximately the effectiveresistance of a properly coupled ships antenna of moderate size at a wave length of1000 meters. Austin] Experiments in Long-Distance Radiotelegraphy 321. Fig. 2 322 Bulletin of the Bureau of Standards TABLE II Birmingham Received at Brant Rock [, No. 3 A= 1000 «=33ainp. July Is= = 3750 27 amp. July Distance, Nautical Miles Received Current _6 10 amp. Distance, NauticalMiles Received Current10 amp. 14 8 a. p. m. 2250 105004600 O <* 14 p. 2260 30001370 O <* {a <t•1 8 p. 8 a. m. 110 256 N 2100520 2. a. 120266 N 520180. 2 p. m. 335 157 (6•1 p. m. 345 67 8 p. m. 415 N 336 p. m. 425 N 77 16 8 a. m. 550 77 16 a. m. 560 49 2 p. m. 626 54 p. m. 636 H. Stat. 8 p. m. 702 N 210 p. m. 712 N 106 17 8 a. m. 854 H. Stat. 17 a. m. 864 26 2 p. m. 927 p. m. 937 Stat. 8 p. m. 1000 N 19 p. m. 1010 N 10 18 8 a. m. 1170 H. Stat. 18 a. m. 1170 2 p. m. 1185 H. Stat. p. m. 1185 8 p. m. 1200 N 51 p. m. 1200 N 44 19 8 a. m. 1152 H. Stat. 19 a. m. 1152 26 2 p. m. 1103 H
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