The KTU 709 TACAN System is composed of the KTU 709 TACAN unit, KDI 572/KDI 574 Master Indicator, optional KDI 573 Slave Indicator, the KI 203 or KI 229 Bearing Indicator and the KA 60 TACAN Antenna. This system provides distance, bearing, groundspeed and time-to-station information with respect to a selected TACAN or VORTAC ground station.
The KTU 709 is a remote mounted 252 channel TACAN unit employing the latest state of the art,solid state transmitter and large scale integrated circuit (LSI) technology. The TACAN unit is operational with any DC power source from 18 to 33 volts. All tuning is done electronically with the incorporation of a single crystal digital frequency synthesizer. Channel selection is controlled by a serial digital data stream fed to the KTU 709 from the KDI 572/574.
The TACAN systems operating channel is selected through the KDI 572/574 indicator which is hardwired to accept ARINC 2X5, shifted BCD or slip code parallel tuning. There is also a provision for serial BCD tuning.
The KDI 572 Master Indicator provides the ability to select NAV 1 or NAV 2 as the TACAN frequency control source while also providing the Hold and ON-OFF functions. The KDI 574 does not have an ON-OFF, NAV 1, HOLD, NAV 2 SWITCH.
The KTU 709 TACAN (PN 066-01074-0000/0002,-0050) generates a synthesized VOR composite output when a bearing signal has been acquired by the unit. The TACAN VOR composite signal may interface with converter-driven VOR instruments or area navigation systems such as the KNS 81-0030/0034 RNAV. The KTU 709 (PN 066-01074-0001) may output the TACAN VOR composite format only when the designated tuning source for the TACAN is selected and when a frequency HOLD operation is not attempted. This provides better pilot management of the
TACAN bearing information and is a result of the TACAN signal being comprised of both distance and bearing information. (See Section 3.1)
Possible tuning sources for the KTU 709 include KRC Silver Crown NAV COMM’s such as the KX 170A and KRC RNAV receivers such as the KNS 81-0030/0034. The Gables G-3849 TACAN control head or the Gold Crown KFS 560B tuning head may also be used. The KFS 579A TACAN (PN-071-01281-XX) and the KFS 579A NAV/TAC (PN 071-01291-XXXX) also tune the KTU 709 to all 252 TACAN channels. The NAV/TAC version when in the NAV mode will tune all 200 VOR/ILS frequencies and paired DME frequencies.
If a KRC NAV receiver is used for TACAN tuning, the number of available TACAN channels is limited to 200. (See Table 3-2) This is due to the fact that 52 TACAN channels are paired with frequencies in the COMM band. These are channels 1 through 16 and 60 through 69, which correspond to VHF frequencies 134.40 MHz through 135.95 MHz and 133.30MHz through 134.25MHz respectively. It should also be noted that TACAN channels which are paired with localizer frequencies cannot be tuned using a NAV receiver. This is due to the fact that when these frequencies are selected, an ILS enable will be produced which will reconfigure the NAV converter to the localizer configuration. There are 40 localizer frequencies which are paired with TACAN channels.
These localizers are on frequencies having an odd .1MHz place value and in the range from 108.10MHz to 111.95MHz, inclusive. These frequencies are paired with all even numbered TACAN channels from 18 to 56, inclusive. In order to provide tuning on these localizer-paired