. The Bell System technical journal . IVING POINT EARTH(b) VERTICAL PLANE DIRECTIVE PATTERNS (NOT DRAWN TO SCALE) Fig. 22—Paths of short waves over long distances as determined by the ionosphere. Figure 23 indicates the elements of the Musa. It consists of a rowof rhombic antennas lined up in the direction from which signals areexpected. Each rhombic antenna is connected by a transmission lineto a phase shifter and the outputs of the phase shifters are connectedto a receiver. These phase shifters may be so adjusted as to cause anydesirable phase additions from the separate antennas. By changin
. The Bell System technical journal . IVING POINT EARTH(b) VERTICAL PLANE DIRECTIVE PATTERNS (NOT DRAWN TO SCALE) Fig. 22—Paths of short waves over long distances as determined by the ionosphere. Figure 23 indicates the elements of the Musa. It consists of a rowof rhombic antennas lined up in the direction from which signals areexpected. Each rhombic antenna is connected by a transmission lineto a phase shifter and the outputs of the phase shifters are connectedto a receiver. These phase shifters may be so adjusted as to cause anydesirable phase additions from the separate antennas. By changingthe adjustments on the respective phase shifters the direction ofreception may be altered. In this diagram a row of antennas is shownas connected through phase shifters to receiving branch A with thephase shifters adjusted to produce a directive pattern as indicated inthe neighboring diagram marked branch A and drawn dotted. Intobranch A will therefore come the signals which arrive from one trans- 644 BELL SYSTEM TECHNICAL JOURNAL. RADIO EXTENSION LINKS TO TELEPHONE SYSTEM 645 oceanic path at the lower angle. Beneath this row of phase shiftersis indicated a second set connected in parallel with the first set. Thesecond set is adjusted somewhat differently so that the receiver inbranch B will receive signals over the path with the higher angle asindicated by the solid line directive pattern in the neighboring two separate signals may therefore be separately , however, they do not arrive at identical times they cannot beadded without producing distortion. By interposing a delay in theoutput branch of the one arriving earlier, which in this case is branchA, they may be added directly into a single audio output. In thiscase if one branch fades the other will continue to receive the signal,and while both are receiving a better signal-to-noise ratio obtains. A cathode ray oscillograph is connected on the outputs of thesereceivers as indicated in the diagr
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
