PS Engineering PMA450 Pilot’s Guide - Manual (Page 6)

Page 6 202-450-0000 PMA450 Pilot Guide Rev. 3
complete and uninterrupted announcements.
The pilot microphone will be heard on the speaker and headsets when the
pilot PTT is used.
The copilot can continue to use the selected com radio while the pilot will be
heard over the speaker.
To exit PA mode, push and hold the
middle line-select button again until
PUBLIC ADDRESS is off or cycle
power on the audio panel.
Marker Beacon Operation (9) ( p/n 050-450-0100, only )
The Marker Beacon Receiver uses visual and audio indicators to alert you
when the aircraft passes over a 75
MHz transmitter.
The audio from the Marker Beacon
Receiver can be heard by pushing the
"MKR" button. AUD will light up
green.
The Blue lamp, labeled “O”, is the
Outer Marker lamp and has an associated 400-Hertz 'dash' tone. The lamp
and tone will be keyed at a rate of two tones/flashes per second when the
aircraft is in the range of the Outer Marker Beacon.
The Amber lamp, labeled “M”, is the Middle Marker lamp and is coupled
with a 1300 Hertz tone. It is keyed alternately with short 'dot' and long 'dash'
bursts at 95 combinations per minute.
The White lamp, labeled “I”, is the Inner marker and has a 3000 Hertz 'dot'
tone. The lamp and tone will be keyed at a rate of six times per second.
Holding the MKR button for 1 second activates marker test lamp, labeled "T/
M" and illuminates all three lamps simultaneously to assure the lamps
(internal and external) are in working order. Test mode does not activate
MM autopilot sense output. Releasing the button returns to the last sensitiv-
ity.
Pressing the marker mode select (“MKR”) for one second, while beacon
audio is active, will also cause the marker audio to mute for that beacon. The
next beacon received will re-activate the audio.
The marker beacon receiver audio volume can be adjusted from the menu.
Press RADIO → VOLUMES →
MARKER, and turn the small knob to
adjust the marker beacon volume. The
green volume bar and numerical readout