Marker Beacon Receiver; Marker Beacon Signal Sensitivity; Figure 4-3 Marker Beacon - Garmin G1000 Reference Manual

Marker Beacon Receiver

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 4-4). The
outer marker frequency is 400 Hz with a blue indicator,
the middle marker frequency is 1,300 Hz with an am-
ber indicator and the inner marker frequency is 3,000 Hz
with a white indicator. Refer to Table 4-1 for a summary
of the marker beacon signal characteristics.
When the MKR/MUTE key is selected, the annuncia-
tor light becomes illuminated and the audio signal can be
heard over the speaker or headsets during marker recep-
tion.
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.
NOTE: The marker beacon receiver lights operate
independently of the marker beacon audio and
cannot be turned off.
Garmin G1000 Cockpit Reference Guide for Cessna Nav III
SECTION 4 – AUDIO PANEL

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.

Figure 4-3 Marker Beacon

The lamp and audio keying of the marker beacon re-
ceiver are summarized in Table 4-1.
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