GLIDESLOPE (GS) MODE OPERATION

TM 11-6625-2975.12

1-13. TEST SET OPERATION. (CONT)

Test set can be returned to preset condition using STD key the same as described for VOR mode.

GLIDESLOPE (GS) MODE OPERATION

When a standard glideslope (GS) rf carrier frequency is selected (see table 2-11), test set

automatically switches to GS mode preset condition. The rf output signal from test set simulates a

glideslope ground station signal with the following parameters:

SIGNAL

CHARACTERISTIC

OUTPUT PARAMETER

Glideslope rf carrier

Selected standard glideslope ground station frequency.

frequency

Rf carrier modulation

90 Hz/150 Hz AM composite audio signal.

Amplitude (o/o) modulation

40.0 percent per tone, on beam center.

DDM

0.000.

U/L (150 Hz) or D/R (90 Hz)

U/L (150 Hz).

status indicator

Operation in glideslope mode is the same as in Iocalizer mode except DDM is selectable in standard

preset steps of 0.000, 0.045, 0.091, 0.175, and 0.400, or in 0.001 increments to

0.800 through keyboard entry. DDM can be slewed in either direction in 0.002 increments. Percent

modulation is variable from 10.0 to 80.0 percent. The 1020 Hz audio signal cannot be added to the

glideslope signal.

MARKER BEACON (MB) MODE OPERATION

When the standard marker beacon rf carrier frequency (75.000 MHz) is selected, test set auto-

matically switches to MB mode preset condition. The rf output signal from test set simulates a

marker beacon ground station signal with the following parameters:

SIGNAL

CHARACTERISTIC

OUTPUT PARAMETER

Marker beacon rf carrier

75.000 MHz.

frequency

Rf carrier modulation signal

400 Hz AM audio signal.

Amplitude (%) modulation

95.0 percent.

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