. The Bell System technical journal . differs considerably fromthat observed under line-of-sight conditions. Consider, for example. which shows the beams of the transmitting and receiving antennaselevated simultaneously. The variation of received power can be calcu-lated from (13). As an example, consider the 188-mile circuit between REFLECTION THEORY — PROPAGATION BEYOND THE HORIZON 641 Crawford Hill, N. J., and Round Hill, Mass., for which experimentaldata is published. For this circuit a = ° (3 db points) and di = 1°(4/3 earth radius). The tal)le below gives the calculated variat
. The Bell System technical journal . differs considerably fromthat observed under line-of-sight conditions. Consider, for example. which shows the beams of the transmitting and receiving antennaselevated simultaneously. The variation of received power can be calcu-lated from (13). As an example, consider the 188-mile circuit between REFLECTION THEORY — PROPAGATION BEYOND THE HORIZON 641 Crawford Hill, N. J., and Round Hill, Mass., for which experimentaldata is published. For this circuit a = ° (3 db points) and di = 1°(4/3 earth radius). The tal)le below gives the calculated variation of re-ceived power as angle d-i is varied. 6; = 1° ° ° ° ° ° 2° °10 logio {Prx/Pri) = 0 12 15 The received power versus elevation angle, 7 = 02 — ^i , is plotted inFig. 10. The calculated and experimental curves are in good agreement. If the beams of the antennas are steered simultaneously in the hori-zontal plane. Fig. 11, the calculation of the variation of received power is. if) _i LU u UJQ LU o Q. QLU> LUU wa. LU > -8-10-12 -14 > -16 -18 -20 -22 0 c \\ \ -^ \ > \ N N \ \ \ \ \ \ EXPERIMENTAL \ \ REFLECTION THEORY n\ \ k. ^ k< ^. ^-N X^ ) ^. » 0 VERTICAL ANGLE, /, IN DEGREES Fig. 10 — Relation between received power and vertical angle y. 642 THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1957 comparatively simple. In horizontal steering, the intersection of the axesof the antemia beams moves along line AB in the figure labelled Crosssection at 0. If the intersection of the beams mo\ed along the circleA-C, the recei\ed power would not change. The decrease in power causedby moving the beams from position ^4 to B is given by (13). The calcu-
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
