PA FUNCTION
A passenger address function is provided by pressing
the PA key. Push-to-talk (PTT) must be used to deliver PA
announcements over the headsets.
SPEAKER
All of the radios can be heard over the cabin speaker.
Pressing the SPKR key selects and deselects the cabin
speaker. Speaker audio is muted when the PTT switch
is keyed.
The speaker volume is adjustable above and below a
nominal value. Contact a Garmin-authorized service cen-
ter for details.
MARKER BEACON RECEIVER
Description and Operation
The GMA 1347 marker beacon is used as part of the
ILS system. The marker beacon receiver is always ON and
receives at 75 MHz. The GMA 1347 provides a marker
audio muting capability.
The receiver detects the three (3) marker tones, outer,
middle and inner, and illuminates the appropriate mark-
er beacon indicators. The marker indicators are located to
the left of the Altimeter on the PFD (Figure 6A.3.3). The
outer marker frequency is 400 Hz with a blue indicator,
the middle marker frequency is 1,300 Hz with an amber
indicator and the inner marker frequency is 3,000 Hz with
a white indicator. Refer to Table 6A.3.1 for a summary of
the marker beacon signal characteristics.
When the MKR/MUTE key is selected, the annun-
ciator light illuminates and the audio signal can be heard
over the speaker or headsets during marker reception.
190-00378-02 Rev. A
When the MKR/MUTE key is annunciated and a mark-
er beacon tone is received, pressing the MKR/MUTE key
mutes the audio but does not affect the annunciators. The
audio returns when the next marker signal is received. If
the MKR/MUTE key is pressed during signal reception,
while marker beacon audio is muted, marker audio and
the MKR/MUTE key annunciator light are turned off.
The marker beacon audio output level is adjustable by
a Garmin-authorized service center.
Marker Beacon Signal Sensitivity
The HI SENS key can be pressed for increased marker
beacon signal sensitivity. The HI SENS function is used
to receive an earlier indication of nearing a marker during
an approach.
Garmin G1000 Audio Panel Pilot's Guide
NOTE: The marker beacon receiver lights operate
independently of the marker beacon audio and
cannot be turned off.
NOTE: The GMA 1347 is capable of driving
external marker beacon lamps.
Figure 6A.3.2 Marker Beacon
OPERATION
6A-7
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