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时间:2011-03-20 12:17来源:蓝天飞行翻译 作者:admin
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 5.  Localizer Antennas
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 A.  Two localizer antennas with dual rf output ports are installed in the nose radome. One antenna is mounted above and the other below the weather radar antenna. Both rf ports of the lower antenna and one rf port of the upper antenna are connected to the VOR/LOC antenna switches to provide localizer rf to the three VOR/ILS receivers.
 6.  VOR/LOC Antenna Switches
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 A.  Five antenna switches, installed behind the VOR/ILS receivers on shelves El-2 and El-3 of the main equipment center, select either the VOR antenna or the localizer antenna as an rf source for the associated VOR/ILS receiver. The switches have a fail-safe (power off) characteristic which connects the localizer antenna to the VOR/ILS receiver. Switching action is controlled by the autopilot localizer mode logic circuits in autopilot accessory boxes No. 1 and 2.
 7.  Glide Slope Antennas
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 A.  AF 121, 122, 155, 156, 158-160, 162-171, 174-182, 185-190, AND AF 157, 161, 183, 184 WITH SB 34-2264; VM ALL, a total of three glide slope antennas, two track and one capture are installed. The track antennas are single element tunable I-slot type units located one each on the leading edge of the aft nose gear wheel well doors. The capture antenna, a nontunable unit, is located in the nose radome.
 EFFECTIVITY

 AF 121, 122, 155-171,  CONFIG 3 174-190, 195-199;  01 Page 4 VM ALL  Sep 25/94

34-31-00
 B.  AF 157, 161, 183, 184 WITHOUT SB 34-2264, a total of six glide slope antennas are installed in the aft nose gear wheel well doors. Each door cavity houses one track antenna, two capture antennas, a hybrid antenna coupler and interconnecting coaxial cables. The track antenna is installed in the door leading edge. On AF 157, 161, 183, the track antennas are single element tunable I-slot type and on AF 184, dual element nontunable I-slot type. The capture antennas are two element tunable arrays installed in the outer side of each door parallel to the longitudinal axis. The hybrid within the door cavity provides impedance matching and combining the rf outputs of the two capture antennas.
 8.  Glide Slope Antenna Hybrid
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 A.  AF 121, 122, 155, 156, 158-160, 162-171, 174-182, 185-190, AND AF 157, 161, 183, 184 WITH SB 34-2264; VM ALL, One hybrid antenna coupler is installed at station 400. The hybrid couples the glide slope rf signal output from No. 1 glide slope antenna coaxial relay to No. 1 and 3 receivers.
 B.  AF 157, 161, 183, 184 WITHOUT SB 34-2264, two additional 4-port type hybrid antenna couplers are installed on glide slope antenna switching panels P31 and P32. Panels P31 and P32 are on the forward side of station 400 bulkhead, forward of main equipment rack E1. The station 400 hybrids combine the rf output of the track and capture antennas to provide a single glide slope rf input for the receivers.
 9.  Glide Slope Antenna Coaxial Relays
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 A.  AF 121, 122, 155, 156, 158-160, 162-171, 174-182, 185-190, AND AF 157, 161, 183, 184 WITH SB 34-2264; VM ALL, two coaxial relays are mounted one each on glide slope antenna switching panels P31 and P32. The relays switch the glide slope rf signal from the nose radome capture antenna to the landing gear door track antenna when the landing gear is down.
 B.  AF 157, 161, 183, 184 WITHOUT SB 34-2264, the relays eliminate spurious capture antenna signals which cause loss of glide slope capture when in the track antenna configuration and the airplane is flown at high bank angles by opening the glide slope capture antenna rf circuit when the landing gear is down.
 10. Glide Slope Antenna Test Switches and Annunciators.
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 A.  AF 121, 122, 155, 156, 158-160, 162-171, 174-182, 185-190, AND AF 157, 161, 183, 184 WITH SB 34-2264; VM ALL, Two glide slope antenna test switches and associated annunciators labeled G/S 1 ANT and G/S 2 ANT are installed on center instrument panel P2. The switches and annunciators provide a means for checking operation of the coaxial relays.
 11. Flight Instruments
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 A.  Radio Magnetic Indicator/Radio Digital Distance Magnetic Indicator
 (1)  Two radio magnetic indicators (RMI's), or one radio digital distance magnetic indicator (RDDMI) and one RMI, are installed on each pilot's instrument panel. Each VOR/DME RMI/RDDMI displays airplane magmetic heading, VOR bearing and DME distance while each ADF RMI displays airplane magnetic heading and ADF bearing.
 EFFECTIVITY
 AF 121, 122, 155-171,  CONFIG 3 174-190, 195-199;  01 Page 5 VM ALL  Sep 25/94

34-31-00
 (2)  
 
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