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11
FI\d
MI.]LTIPAITI
ADJIJSTMENT
F[,4
radio
signals behave
somewhat
like
light
waves,
and when
there
are
buildings
or
other objects
near
the
receiver antenna,
the
signals
are reflected
as
shown
in
the
diagram. When these
reflect:d
signals
enter
the
antenna
at
the
same
time
as
the
direct
signals,
the two
interfere
with
each
other and
pro-
duce distortion
in
the
receiver.
This is
termed
"multipath distortion".
The result
of
multipath
is
distortion
in
the
sound
and poor
stereo separation.
To
prevent
such multipath
interference, use the
most directional
antenna
you
can
obtain
(one
with
the
most elements)
and
point
it
either directly
at
the
station's
broadcasting antenna
or
in
a direction
where
no
multipath
effects are
noticed.
To
deter-
mine
the
direction
of
least
multipath
interference,
this unit
is equipped
with
a set
of
special
outputs.
Adjust your
antenna
position
by the
following
method.
DIRECT WAVE
AND
R
EFLECTED WAVE
1.
ADJUSTMENT WITHOUT AN
osctLLoscoPE
O
lMake
the
connections
shown
in the
diagram
and
turn
the
SELECTOR switch
to
the
AUX
position.
O
Tune
in
a stereo broadcast.
The
sound coming
from
the
L
channel speaker
will
be
free
of
distortion, while significant distonion
is
heard
from the
B channel
speaker.
O
Adjust
the
OUTPUT
LEVEL
controls
so
that
sound
is
heard
only
from
R
channel
speaker'
O
Rotate
the
antenna
until
the
volume
of
the
B
channel speaker
is lowest.
At this
point,
multi-
path distortion
will
be
minimized and
the
antenna
should
be
permanently
iixed
in
this
position.
2.
ADJUSTMENT
WITH
AN
oscrLLoscoPE
Connect
an
oscilloscope
to
the
[/]ULTIPATH
out-
puts
as
shown
in the
diagram.
Use
an
oscilloscope
with
a vertical deflection sensitivity
of
more
than
lOmv/cm
and a horizontal deflection sensitivity of
more
than
50mV/cm. Tune
in an
Fl\,4
station
and
adjust
the
oscilloscopd
so
that
the
wave
pattern
is
easy
to
see.
Adjust your
antenna
so
that
the
multi-
path
interference
is
minimized
as
shown
in the right
hand
square
in
the
diagram.
MULTIPATH outputs
on
rear
panel
(Shielded
wire)
ffil
Lffi]I
Much Multipath
lnterference
tml
[ffi]r
Little
Multipath
lnterference
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