Cessna 182S Skylane Information Manual page 320

CESSNA
MODEL
182S
SECTION
9 -
SUPPLEMENTS
SUPPLEMENT
6
-
FAA
APPROVED
ADF
OPERATION
NOTES:
ERRONEOUS ADF
BEARING DUE
TO RADIO
FREOUENCY
PHENOMENA:
ln the
U.S.,
the
FCC, which assigns
AM
radio
frequencies,
occasionally
will
assign
the
same frequency
to
more than
one
station
in an
area.
Certain conditions, such
as Night Effect,
may
cause signals from such stations
to overlap. This
should be
taken
into consideration when using AM broadcast station for navigation.
Sunspots and atmospheric phenomena may occasionally
distort
reception so that
signals
from two stations on the same
frequency
will
overlap.
For this reason,
it
is
always wise
to
make positive
identification
of the
station being tuned,
by
switching
the
function
selector to ANT and listening for station call letters.
ELECTRICAL STORMS:
ln the vicinity of
electrical
storms, an ADF
indicator pointer tends
to swing from the
station
tuned toward the center
of
the storm.
NIGHT EFFECT:
This is a
disturbance particularly
strong just after sunset
and
just
after
dawn.
An ADF
indicator
pointer may swing
erratically
at
these
times. lf
possible, tune to the most poweÉul station at the
lowest
frequency.
lf
this
is
not
possible, take
the
average
of
pointer
oscillations to determine relatíve station bearing.
MOUNTAIN EFFECT:
Radio
waves
reflecting
from the surface of
mountains
may
cause
the pointer to fluctuate or show an erroneous bearing. This
should
,b"e,,rjfl1""
into
account when taking bearings over
mountainoust
COASTAL
REFRACTION:
Radio waves may be
refracted
when
passing
from
land
to sea
or
when moving parallel to the coastline. This also should be
taken
into
account.
Dec
1/97
s6-11