Section 2
Communicating with the GNC 250XL
The GNC 250XL features a digital VHF radio that provides a seamless transition
from communication to navigation, bringing the two most important functions in fly-
ing together in one panel-mount unit. The GNC 250XL operates in the aviation voice
band, from 118.000 to 136.975 MHz, in 25 kHz steps.
Communication frequencies are selected by activating the cursor in the
standby
frequency field
and using the inner and outer knobs to dial in the desired frequency.
A frequency may also be quickly selected from the navigation database by simply
highlighting the frequency and pressing the
E
key. Once a desired frequency is dis-
played in the standby field, it may be made the active frequency by pressing the
@
key.
Note that the active frequency may not by accessed directly
. Whenever the cursor is
active in the comm window, the standby frequency will be highlighted.
To access the standby frequency, press
C
.
This allows you to change the megahertz (number to the left of the decimal) by
rotating
O
and the kilohertz (number to the right of the decimal) by rotating
K
. If
you would like to keep the standby field ‘hot’ (ready for an immediate frequency
change), leave the cursor active in the comm window. To remove the cursor, press
C
twice after you have selected the desired frequency.
To make the standby frequency the active frequency, press
@
.
The frequencies will be flip-flopped and you’ll be able to transmit and receive on
the frequency previously entered as standby. This can be done at any time, regardless
of cursor or GPS status.
33
CDI page with standby field active. To flip-flop the
frequencies, press
@
.
CDI page with cursor inactive.
SECTION
2
COMM FEATURES
Overview
250xl manual 2 7/17/98 1:27 PM Page 33