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FM-AM RADIO
INTRODUCTlON
TO FM
There are many
advantages of
FM radio-high fidelity reception relatively free from
noise
with a fine selection of programs, many of which are not otherwise available
.
Your
VOLVO
AM·FM radio is designed to make the most
of
these advanta ges
;
it brings you the
enjoy·
ment of bot h superioT radio performance and
excellence
of programs.
FM
RECEPTION
RANGE
The
effective
ran
ge
of
FM radio
stations
is
not
as
great
as
AM
stations.
This is mainly due
to the fact th at FM
radio signals
travel throu gh the
air
in
straight
lines
and are easily
blocked by obstacles
such
as hill ranges and
the curvature
of
the
earth.
In
effect,
FM radio
signals behave as
light
waves.
Beca
use
of
this
characteristic,
th
e
usual ran
ge
of
an
FM
station
may
be only 25 miles.
However,
you will
f
ind
there to be exception s to this range
.
FM STATION
•
f""~
EFFECTI VE RECEPT I ON RANGE
OF FM STATION
However, within the effective broadcast range of a station, the FM signals are easily
reflected and scattered into areas where AM reception
is
almost impossible-such as
under bridges,
in underpasses and among tall
buildings.
As
you drive away from the radio station and into weaker signal areas, you will notice a
decrease in FM performance
.
The radio will also start to pick·up interference
.
The
inter-
ference is due to the fact that the radio relies on a certain minimum level of signal stren gth
to provide
noise-free reception. Therefore, when listening to a weak signal
,
it is normal for
the radio to pick up noise from surrounding cars and other electrical devices.
STRONG SIGNAL AREA-RECEPTION
I S GOOD, CLEAR AND NOl SE FREE
WEAK S I GNAl AREA-RECEPTI ON
WILL BE POOR. EXHIBITING
NOISE FADE & FL UTTER.
In
weak signal areas, you will
also
notice that the
radio program
may fade out completely
or fl utter
in
a similar manner to a TV picture when
an airplane
is flying overhead
.
This
occurs because the weaker signals are
easily blocked
from the radio by surrounding
objects. Fade-out and flutter are most pronounced
when
driving in areas having valleys
or hill ranges
.
~-.
RECEPTION IS FAIR IN THIS AREA AS THERE
ARE NO OBSTRUCTIONS BETWEEN FM STATION
AND RADIO.
AFe CIRCUIT
RECEPTION I S POOR I N TH I S
AREA AS S I GNAl I S BLOCKED
BY RANGE OF H I LlS
The AFC (Automatic Frequency Control)
circuit
reduces the
effect of FM drift.
It
keeps
the
radiO
tuned to the station whlch you have
selected.
However,
the ability of
the AFC
to
hold
the
radio
tuned to
a
station
is
dependent
upon
the
strength of
the FM
signal;
that
is,
the AFC Will hold the radiO tuned
to
a stronger
station
much
better than it will to
a weak
station
.
Therefore,
as you
drive away from a station
and the signal becomes
weaker,
it
is possible for the AFC
circuit
to automatically tune
in a
closer,
more
powerful station
.
ANTENNA
CONSIDERATIONS
The regular automotive antenna
installed
with your radio will provide sufficient reception
of FM radio stations.
However,
due to a characteristic of the FM signal, best reception
will be obtained by adjusting the antenna to a height of approximately 30
inches_
You
will also find that a 30
inch
antenna height will provide sufficient reception of AM
stations in most
areas.
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