Scientific Papers of the Bureau of Standards Volume 7

Scientific Papers of the Bureau of Standards Volume 7

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 edition. Excerpt: ...top antenna was approximately 40 meters and the wave length 1000 meters; from the Hertz radiation formula ' The ratio of received to radiated energy 17 = 1. 30.10_' For stronger signals the received energy may, of course, be measured directly on the thermoelement in the antenna, the perikon circuit being removed or coupled so loosely that no appreciable energy is taken up. By the last arrangement watch can be_ kept by means of a telephone attached to the perikon to see that no station or other disturbance comes in to affect the measurements. I By this method the following results were obtained from the station at the Washington Navy Yard, 6 miles away: Received current at the Bureau of Standards I = 1.4. 10" amp. High frequency resistance of receiving antenna R=2 5 ohms. The received energy E = PR =4.9.10.-5 watts. The navy yard station, rated at 2 K W, has a wave length of 900 meters and its flat top antenna has a height of 55 meters. From the radiation formula, R= 5.92 ohms. The current in the antenna during the experiment was 13 amp. Hence the radiated energy E= 1. 103 watts. The ratio of energy received to that sent 77 This ratio, considering the short distance, is very small and is to be explained by the fact that the path of the waves lay practically all the way over the city of Washington. U. S. NAVAL W11E1.Ess TELEGRAPHIC LABORATORY. Washington, October I, 1910. Very little experimental data has been given on the relative magnitudes of the currents in coupled circuits under different conditions of coupling. Fischer ' has shown that, when a circuit containing a spark gap is coupled to a second oscillatory circuit and this second circuit in tum very loosely coupled to a third circuit containing a...show more

Product details

  • Paperback | 168 pages
  • 189 x 246 x 9mm | 313g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236946529
  • 9781236946522