Section 1: Communicating With The Gnc 420 - Garmin GNC 420 Pilot's Manual & Reference

Communicating with the GNC 420
The GNC 420 features a digitally-tuned VHF COM radio that provides a seamless
transition from communication to navigation, bringing the two most important functions
in fl ying together in one panel-mounted unit. The GNC 420's COM radio operates in the
aviation voice band, from 118.000 to 136.975 MHz, in 25 kHz steps (default). For Euro-
pean operations, a COM radio confi guration to allow for 8.33 kHz steps is also provided
(see pages 148-149).
Volume
COM radio volume is adjusted using the
increase volume, or counterclockwise to decrease volume.
Squelch
The COM radio features an automatic squelch, providing maximum sensitivity to
weaker signals while rejecting many localized noise sources. You may wish to override
this automatic squelch function when listening to a distant station or when setting the
k
desired volume level. The knob allows you to disable the automatic squelch and keep
the COM audio open continuously.
To override the automatic squelch, press the
to return to automatic squelch operation.
Section 1
k k
knob. Rotate the
k
knob momentarily. Press
knob clockwise to
Press the k knob momentarily to override the
automatic squelch. Note the "RX" receive
indication when receiving a station.
k
again
"TX" appears at the upper right corner of the
screen while transmitting.
COM
1
Radio Volume
Auto Squelch
21