Federal Aviation Administration, DOT Section 171.311 TABLE 1b - CHANNELS - Continued Channel pairing DME parameters Interrogation DME No. 118Z .................. 119X .................. 119Y .................. 119Z .................. 120X .................. 120Y .................. 121X .................. 121Y .................. 122X .................. 122Y .................. 123X .................. 123Y .................. 124X .................. ** 124Y .............. 125X .................. ** 125Y .............. 126X .................. ** 126Y .............. VHF freq. MHz .................... 117.20 117.25 .................... 117.30 117.35 117.40 117.45 117.50 117.55 117.60 117.65 117.70 117.75 117.80 117.85 117.90 117.95 MLS angle freq. MHz 5090.1 .................... 5090.4 5090.7 .................... .................... .................... .................... .................... .................... .................... .................... .................... .................... .................... .................... .................... .................... Reply Pulse codes MLS Ch. No. Freq. MHz 697 .............. 698 699 .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. 1142 1143 1143 1143 1144 1144 1145 1145 1146 1146 1147 1147 1148 1148 1149 1149 1150 1150 DME/P Mode DME/N Sections IA Sections FA Sections .............. 12 36 .............. 12 36 12 36 12 36 12 36 12 36 12 36 12 36 21 .............. 36 21 .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. 27 .............. 42 27 .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. .............. Freq. MHz Pulse codes Sections 1079 1206 1080 1080 1207 1081 1208 1082 1209 1083 1210 1084 1211 1085 1212 1086 1213 1087 12 12 30 15 12 30 12 30 12 30 12 30 12 30 12 30 12 30 Notes: * These channels are reserved exclusively for national allotments. ** These channels may be used for national allotment on a secondary basis. The primary reason for reserving these channels is to provide protection for the secondary Surveillance Radar (SSR) system. S 108.0 MHz is not scheduled for assignment to ILS service. The associated DME operating channel No. 17X may be assigned to the emergency service. (b) Polarization. (1) The radio frequency emissions from all ground equipment must be nominally vertically polarized. Any horizontally polarized radio frequency emission component from the ground equipment must not have incorrectly coded angle information such that the limits specified in paragraphs (b) (2) and (3) of this section are exceeded. (2) Rotation of the receiving antenna thirty degrees from the vertically polarized position must not cause the path following error to exceed the allowed error at that location. (c) Modulation requirements. Each function transmitter must be capable of DPSK and continuous wave (CW) modulations of the RF carrier which have the following characteristics. (1) DPSK. The DPSK signal must have the following characteristics: bit rate .............................. bit length ........................... logic - 0 - ............................ logic - 1 - ............................ phase transition ................ phase tolerance ................ 15.625 KHz 64 microseconds no phase transition phase transition less than 10 microseconds Section10 degrees The phase shall advance (or retard) monotonically throughout the transition region. Amplitude modulation during the phase transition period shall not be used. 849 VerDate Sep<11>2014 08:20 May 17, 2019 Jkt 247048 PO 00000 Frm 00859 Fmt 8010 Sfmt 8010 Y:\SGML\247048.XXX 247048