TM 55-1510-222-10
Figure 3-14. Radio Altimeter Indicator (RA-315)
3-23. VHF NAVIGATION RECEIVERS (VIR-32).
a. Introduction. The VHF navigation receivers
(FIG. 3-15) provide 200, 50-kHz spaced, VOR/ localizer
channels from 108.00 through 117.95 MHz, 40
glideslope channels, automatically paired with localizer
channels, and a marker beacon receiver. The digital
navigation receiver provides VOR, LOC, and GS
deviation outputs, high and low level flag signals,
magnetic bearing to the station, to-from information,
marker beacon lamp signals, and VOR and marker
beacon audio outputs. The navigation receivers are
powered through the 2-ampere VOR NO. 1 and VOR
NO. 2 circuit breakers which are located in the
overhead circuit breaker panel (FIG. 2-6).
b. Operating Controls. All operating controls for
the navigation receiver are located on the navigation
receiver control unit.
(1) Frequency Indicator. Indicates the operating
frequency of the receiver.
(2) Frequency Control. Two concentric tuning
knobs control the operating frequency. The larger knob
changes the three digits to the left of the decimal point
in 1-MHz steps. The smaller knob changes the two
digits to the right of the decimal point in 0.05 MHz
steps. The two, frequency select switches are
independent of each other so that the upper and lower
rollover of the 0.1 MHz digit will not cause the 1.0 MHz
digit to change.
(3) NAV TEST Pushbutton. When pressed, the
following indications are presented:
(a) RMI. Single needle indicates 5°.
(b) CDI. Lateral deviation to the right.
Glideslope deviation down.
c. VOR Receiver Operation.
(1) Equipment Turn-On. The VIR-32 receiver
and the NAV control are turned on by rotating the
VOL/OFF control clockwise.
(2) VOR Operating Procedures.
1. Frequency controls Set desired
frequency.
2. VOL control - As required.
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