NAD 7120 - Antenna Terminals and Setup

REAR
PANEL
CONNECTIONS
1. ANTENNATERMINALS.
This
receiver
is
equipped
with
four antenna
terminals;
each
is
a
threaded
metal
shaft
with a
plastic
thumbscrew
and
a toothed
washer
which
will
make secure
contact
either
with bare
wire or
with the
U-shaped
metal
spade
lug
that
is
often
provided
on
antenna
wires.
lf
you
are using
an
antenna
whose
lead-in wires
have
some
other
type of connector,
cut
it off and strip
off
enough
insulation
to expose
approximately
1
cm
(1/z
inch) ol bare
wire on
each
conductor.
To connect
the antenna
wire,
unscrew
the
appropriate
thumbscrew,
place
the spade
lug
or
bare
wire under
the
toothed
washer,
and
turn the
thumb-
screw
clockwise
until
it
is tight.
The toothed
washer
will
grip
the
lug or
wire,
making
a connection
that is secure
both
electrically
and
mechanicallY.
AM. Some
form
of external
antenna
will be
needed
for satislactory
reception,
since
the
7'120 does
not
have a
built-in
AM antenna.
For
most
local broadcasting
stations
a
simple
wire up
to one
meter
(three feet) in
length
will
provide
ample
signal
strength,
and
such a
single-wire
antenna
is
included
with the
receiver.
Connect
one
end ol
the wire
to
the AM
terminal.
The remainder
ol
the antenna
may be
allowed
to
hang down
behind
the
receiver or
may be tacked
in
place
horizontally
along
the
rear of a
wooden-not
metal-shell.
(A
metal
shelf
may
interfere
with reception;
in that case
the wire should
be stretched
out
along
the
wall
away
lrom
the shelving
and
tacked
in
place.)
You may
wish
to
experiment
with
the orientation
of
the
AM antenna,
in
order
to find
the
position
that
provides
the best
reception
of
the stations
you
listen to
most often.
The
short-wire
antenna
usually
will
provide
satisfactory
reception
ol
local AM broadcast
stations
But if
you
wish to
improve
reception
of
distant
AM stations,
attach
a
long-wire
outdoor
antenna
to the
AM terminal.
As its
name implies,
a
"long-wire"
antenna
is
a
simple,
straight
wire whose
length
may
be anything
from
a few
feet up
to about
100 leet
(30
meters),
mounted
parallel
to
the earth
and as
high as
is
convenient.
ln
some
cases
the effectiveness
of a
long-wire
antenna
will be
improved by
connecting
a
second
wire
from
the
Ground
(G)
terminal
to a true earth-ground,
i'e.
a copper-plated
rod driven
several
feet
into the earth.
A substitute
electrical
ground may also
prove
effective:
a cold-water
pipe,
a steam
radiator, or
the
third
hole
of
a
modern
electrical
wall socket.
FM. Some
form of external
antenna
must be
connected
to the
receiver
for effective
reception
of stereo
FM broad-
casts.
A ribbon-wire
"folded
dipole"
antenna
is
supplied
with
the
receiver
to
get
you
started.
When
you
stretch
out
the
ribbon-wire
antenna
you
will
note that
it
is in the
form of a
"T".
The
"crossbar"
portion
of the
Tshould
be stretched
out
horizontally
and
tacked
in
place-on
a
wall, on
the
back of
a
cabinet,
or on
the
floor.
The
"vertical"
section
of
the
T
goes
to
the receiver's
antenna
terminals.
Connect
its two
wires
to
the two
3000
inPut
terminals.
ln
view of
the excellent
sensitivity
of
this
receiver,
you
may
find that
the
ribbon-wire
dipole
antenna
is all
you
need for
reception
of
strong
local stations.
But
it is not
very
efficient
at
rejecting
"multipath"
and
other
forms
of
FM
interference,
and
it cannot
easily
be
rotated
to optimize
its
pickup
pattern for best
reception
of stations
in
different
directions.
Therefore,
in
most cases
you
should
use a
better
antenna.
The
recommended
options,
in order
of
increasing
cost,
are as
follows:
(1)
Abasic
"rabbit-ears"
indoor
TVantenna
without
auxiliary
coils or
tuning
switches.
Electrically,
such
an
antenna
is
just
another
dipole
(similar
to the
ribbon-wire
antenna)
with
its tuned elements
made of
solid
metal, but
with the
advantage
that it can
be rotated.
Stretch
out each
of
its two arms
to a
length of 30
inches
(75
cm),
and orient
them
horizontally
or
at a shallow
angle
upward
(less
than
45 degrees).
The
ribbon-wire emerging
from the antenna's
base should
be connected
to the
receiver's two 300O
termi-
nals
in
place
oI
the
ribbon-wire
antenna supplied
with the
receiver.
Now
for each
station
in turn, after
you
tune the
station
you
can
rotate
the antenna
for best
reception.
(2)
A more elaborate
rabbit-ears
indoor
TV
antenna
with a tuning
switch.
This
type of
antenna
does
NOT
have
greater
sensitivity
than
the simpler
rabbit-ears
unit,
so
iI
your
problem
is that
the signals
you
want
to
receive are
weak and
noisy,
then an
outdoor
antenna
is the only
effec-
tive solution.
But
in cities
and
in large
buildings
where
signals
are strong
but are
contaminated
by
reflected
"mul-
tipath"
signats
that
interfere
with
good
reception,
the
tuning
switch
on an
elaborate
indoor
antenna
may improve
recep-
tion by
reducing
the
interference.
(3)
An electrically
tuned
indoor antenna,
such
as the
Technics
Wing or
B.l.C.
Beam
Box.
Again, such
antennas
usually
do
not
provide
any
advantage
over
the simplest
type
of
"rabbit-ears"
unit
for receiving
weak signals.
But where a
strong
signal
is contaminated
by
interference,lhe
antenna's
aiming
and
tuning
controls
can
reject
the
interference
and
yield
cleaner
reception.
(4)
An outdoor
antenna,
Even
the
finest
indoor an-
tenna,
no
matter
how elaborate,
cannot
fully exploit
the
capabilities
of a
good
FM
tuner.
For
the lowest
noise,
minimum
distortion,
and
largest
choice
of
well-received
broadcasts,
an
outdoor
antenna
is the best
complement
to a
fine tuner.
A
roof-mounted
antenna
has three
fundamental
advan-
tages.
First,
its
large size
yields
better
sensitivity
(pulling in
a stronger
signal
from
the
desired
station)
and a
narrower
directional
pattern
for
more effective
rejection
of
multipath
reflections
arriving
from other
directions.
Second,
its loca-
tion
on a
rool or
tall
mast
places
it above
many sources
of
interference-other
buildings,
passing
cars
and
buses,
etc.
Third,
the strength
of received
FM signals
is directly
propor-
tional
to the
height
of
the antenna
above
the
ground.
lf
you
already
have an
outdoor
television
antenna,
using
a splitter
to extract
FM signals
from
it may
produce
excellent
results.
However,
many
TV antennas
are deliberately
de-
signed
to be
relatively
weak
at
FM frequencies
in order to
minimize
potential
interference
with
TV signals
at
nearby
frequencies
(Channel
6
in the
U.S.).
You may be
able
to use
a splitter
to extract
FM signals
from an
apartment
building's
master
TV antenna
system,
but
usually
this
yields
poor
results
because
many
master antenna
systems
have
"traps"
to stop
FM signals.
The best
choice
is a directional
FM-only
antenna,
mounted
as
high above
ground
as
is
practical,
and
sepa-
rated by
at
least
two
meters
(7
feet)
from
other
antennas,
vertically
and
horizontally.
A shielded
lead-in
cable
will be
mandatory
in most
locations,
both
to minimize
interlerence
and
to
preserve
strong
signals
during
years
of
weathering.
The
cable
may be
either
75-ohm
coaxial
or a
shielded
300-ohm
type.
ll
desired
stations
are
located
in
different
directions
(more
than 90
degrees
apart),
a
rotor
will also
be needed
in order
to aim
the
antenna.
lf
you
are
using
a
75-ohm
coaxial
cable
(either lrom
your
outdoor
antenna
or
from
a master
antenna
system),
connect
it as
follows.
First
remove
any
connector
that
may
have
been
fitted. Strip
off about
an
inch
(2
cm) of
the
outer
insulation
to
expose
the shield
wiring,
fold
back
the shield
and
twist
its
wire strands
together,
then
strip off
a
half-inch
(1
cm)
of
insulation
from
the
center
conductor.
Disconnect
any
antenna
connected
to
the
300O
terminals.
Connect
the
coixial
cable's
center
conductor
to the
75O
terminal
and
connect
the coaxial
cable's
shield
wire to
the adjacent
ground
(G)terminal.
After
you
have
completed
all
of
the antenna
connec-
tions, examine
them
to be
sure
that
adjacent
wires or
connectors
are
not
touching
each
other,
short-circuiting
the
antenna
signal.
2.
PHONO
INPUT.
This
input
is designed
for use
with
phono
cartridges
of
the
moving
magnet,
induced
magnet,
moving
flux, and
moving
iron
(variable reluctance)
types,
and
wiifr
"high-output"
moving-coil
pickups
(i.e.,
those
with
a
rated
output
of
1.0
mVor
greater). The
input
impedance
at
the
Phono
jacks
is 47K
ohms
in
parallel with
100
pE
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