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REAR PANEL CONNECTIONS
1. ANTENNA TERMINALS. Thi s 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.
If 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
(V, inch) of 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 satisfactory reception, since the rece iver 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 of the wire to the
AM terminal. The remainder of 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-shelf.
(A metal shelf may interfere with reception; in that case the
wire should be stretched out along the
wall away from 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
of 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 leng th
may be anything from a few feet up to about 100 feet (30 meters) , mounted parallel to the earth and as high as is
convenient. In 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 T should 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.
In 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 "multi path " 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 ) A basic "rabbit-ears" indoor TV antenna 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
3
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
3000
terminals in place of 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 if
your problem is that the signals you want to rece ive 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
"mu l tipath " signals 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.I.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 , the 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 multi path
refle ctions arriving from other directions . Second, its location
on a roof 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 .
If 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 frequenc ies 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 direct iona l FM- only antenna ,
mounted as high above ground as is practical, and
sepa
rated by at least two meters (7 feet) from other antennas,
vert ically and horizontally. A shielded lead-in cable will be mandatory in most locations, bolh to minimize interference
and to preserve strong signals during years of weathering.
The
cable may be either 75-ohm coaxial or a shielded
300-ohm type . If desired stations are loca ted in different
directions (more than
90 degrees apart), a rotor wifl also
be needed in order to aim the antenna.
If you are using a 75-ohm coaxial cable (either from
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
3000 terminals. Connect the
coaxial cable's center conductor
to the 750 terminal and
connect the coaxial cable's shield wire to the adjacent
ground (G) terminal.
