. The Bell System technical journal . on the Murray Hillpath, is believed to be caused by the mechanism illustrated in Fig. 3(b). SELECTIVE FADING OF MICUOWAVES 71 Hero a roflectinjj; layer is situated l)et\veen the heif^-hts of the li-aiisnii(1(M-and r(>((M\-er. The signal then sulters attenuation due to ie(l(>cti()n of|)art of tlu^ energy from th(> diicct path. Widely separated fie(|nenciesaie affected in like fashion and the outputs of anteinias sjjaced fordixersity Ieception tend to be in agreement although th(> fine structurefachng is usually different. On neither of the exper
. The Bell System technical journal . on the Murray Hillpath, is believed to be caused by the mechanism illustrated in Fig. 3(b). SELECTIVE FADING OF MICUOWAVES 71 Hero a roflectinjj; layer is situated l)et\veen the heif^-hts of the li-aiisnii(1(M-and r(>((M\-er. The signal then sulters attenuation due to ie(l(>cti()n of|)art of tlu^ energy from th(> diicct path. Widely separated fie(|nenciesaie affected in like fashion and the outputs of anteinias sjjaced fordixersity Ieception tend to be in agreement although th(> fine structurefachng is usually different. On neither of the experimental transmission paths is there a Igeularground-i-eflected component of any conseciuence. Due to the roughnessof the giound and the presence of vegetation, the effective reflection coef-ficient is of the order of for eithei- path. (Jiound reflections thus play. Fig. 3—Possible ray paths involved in severe failing, (a) Multiple path trans-mission, (b) Attenuation by reflection from an elevated layer, (c) Abnormalwater reflection on the Murray Hill-Crawford Ilill j^ath. (d) Substandard con-ditions on the Southard Hill-Crawford Hill path. 72 THE BELL SYSTEM TECHNICAL JOIRNAL, JANUARY 1952 no significant part in the fading picture with the exception of the situa-tion illustrated in Fig. 3(c). Occasionally on the Murray Hill path,conditions of atmospheric refraction are such that a strong signal com-ponent is received by virtue of reflection from the water surface ofRaritan Bay. Under normal conditions, the geometry of the path doesnot permit such a reflection. Normally the dielectric constant of the atmosphere decreases withheight above ground so that the ray path usually has a curvature inthe same direction as the earth cur^^ature. However, it is possible for thedielectric constant of the atmosphere to increase with height aboveground (sub-st
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
