Cessna 152 - Page 199

PILOT'S
OPERATING
HANDBOOK
SUPPLEMENT
CESSNA
300
NAV/COM
(TYPE
RT-385A)
The
Cessna
300 N
av/
Com
incorporates
a
variable
threshold
automatic
squelch.
With
this
squelch
system,
you
set
the
threshold
level
for
auto-
matic
operation
-
the
further
clockwise
the
lower
the
threshold
-
or
the
more
sensitive
the
set.
When
the
signal
is
above
this
level,
it
is
heard
even
if
the
noise
is
very
close
to
the
signal.
Below
this
level,
the
squelch
is
fully
automatic
so
when
the
background
noise
is
very
low,
very
weak
signals
(that
are
above
the
noise)
are
let
through.
For
normal
operation
of
the
squelch
circuit,
just
turn
the
squelch
clockwise
until
noise
is
heard
-
then
back
off
slightly
until
it
is
quiet,
and
you
will
have
automatic
squelch
with
the
lowest
practical
threshold.
This
adjustment
should
be
rechecked
periodically
during
each
flight
to
assure
optimum
reception.
All
controls
for
the
Nav/Com,
except
the
standard
omni
bearing
selector
(OBS)
knob
or
the
optional
automatic
radial
centering
(ARC)
knob
located
on
the
course
deviation
indicator,
are
mounted
on
the
front
panel
of
the
receiver-transmitter.
Operation
and
description
of
th~
transmitter/
au-
dio
switching
system
or
audio
control
panel
used
in
conjunction
with
this
radio
are
shown
and
described
in
Section
7
of
this
handbook.
SECTION 2
LIMITATIONS
There
is
no
change
to
the
airplane
limitations
when
this
avionic
equipment
is
installed.
SECTION 3
EMERGENCY
PROCEDURES
There
is
no
change
to
the
airplane
emergency
procedures
when
this
avionic
equipment
is
installed.
However,
if
the
frequency
readouts
fail,
the
radio
will
remain
operational
on
the
last
frequency
selected.
The
fre-
quency
control
should
not
be
moved
due
to
the
difficulty
of
obtaining
a
known
frequency
under
this
condition.
1
July
1978
5