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SECTION Ill
INSTALLATION
3-1.
UNPACKING.
After removing the amplifier from the car-
ton, examine
it for any damage which may have
occurred
in shipment.
Should any sign of damage
be apparent,
immediately
file a claim with the
carrier
stating the extent
of damage.
Check and
retain all shipping tags and cartons
for special
instructions and possible re-use. The Type 3-400Z
tube and chimney are shipped ina Separate carton
to reduce possibility of breakage in shipment.
NOTE
DO NOT
REMOVE
TUBE AND CHIM-
NEY
FROM
CARTON
UNTIL
READY
TO
INSTALL.
The tube is installed by
inserting
it in the socket and exerting
a gentle straight downward pressure on
the tube. DO NOT FORCE TUBE INTO
SOCKET.
Remove
the top cover
from
the amplifier
cabinet by turning the fasteners one-quarter turn
counterclockwise.
Install the 3-400Z
tube in its
socket and place the glass chimney over the tube.
The glass chimney
is aligned and held in place by
three clips on the chassis. Identify the plate lead,
attached
to top of RF
choke RFC1, and attach it
to the heat-radiating plate cap on the 3-400Z tube.
(See figure 5.) Secure
the plate lead, using the
brass
screw
in the center of plate cap. DO NOT
TIGHTEN
SCREW
EXCESSIVELY,
as high torque
applied
to the
plate
cap
cowd
result
in tube
damage.
Replace
the top cover, noting the align-
ment
of the
tab
which
engages
the equipment
interlock switch, and secure it in place by turning
the fasteners one-quarter turn clockwise.
3-2.
LOCATION.
It is very
important
that the amplifier be
piaced in an operating position that enables unob-
structed air circulation directly behind and atthe
top of the
unit.
The air intake for the cooling
blower is located at the rear of cabinet and neces-
sitates exhausting of the warm air out ofthe top of
cabinet.
UNDER
NO CIRCUMSTANCES
SHOULD
ANY OBJECT
BE PLACEDON TOP OF CABINET,
PREVENTING
EXHAUST OF WARM
AIR.
3-3.
POWER REQUIREMENTS.
The
Model
HT-45
Mark
TIA
RF
Linear
Amplifier
requires
an
operating
power
of 155
watts
(115 volts, 60 cycles AC) for the blower
and filament circuits and a plate power supply of
3,000 volts DC at 350 milliamperes. Input connec-
tions for the power and control circuits are made
through
a
multiple-conductor,
number-coded
cable.
The cable is designed
to terminate
at a
barrier-type
terminal
strip and a high-voltage
type
connector
on the Mark
IIA Power
Supply.
Connections
are
shown
in figure 2. In the event
another power
supply is used, careful
attention
must
be
given
to the interconnecting
diagram,
figure 2, and power
supply
schematic
diagram,
figure 8, to insure proper connection.
3-4.
INPUT
AND OUTPUT
CONNECTIONS.
a.
RF Input.
The input connection for the
RF
driving signal is located at the rear
of the
cabinet.
A chassis-mounted,
female, phono-type
connector
is provided
for the input connection.
The
mating connector is supplied with the equip-
ment
and is used by connecting to a short length
of RG-58/U coaxial cable terminated ina connec-
tor mating with the exciter output connector. Refer
to figure 3 for location of the RF input connector
and cabling diagram.
NOTE
For best performance, the input cable
should be less than one-quarter wave-
length
at the
highest
operating
fre-
quency. When the amplifier is used with
an exciter that will not deliver 45 watts
or more of driving power, the ampli-
fier cannot be driven to the rated 1,000
watts
input. In certain cases it may be
desirable
to reduce
the output of ex-
citers,
having
output
capabilities
in
excess of 45 watts, by insertinga3-DB
attenuating pad. For information cover-
ing the installation and construction of
a suitable
attenuator,
see Section VII,
Supplementary
Data.
b.
RF Output.
The output connection for
the RF
output signal is located at the rear of the
cabinet.
The
output
connector
is a
chassis
mounted,
UHF
Type coaxial connector
(SO-239)
and
mates
with a UHF
Type coaxial
connector
(PL-259).
The power output developed
requires
the use of RG-8/U coaxial antenna feed line. The
linear
amplifier
performs
best
when
the load
impedance
is as near to 50 ohms
as is practical.
A
load
impedance
of
50
ohms
reduces
VSWR
(voltage standing wave ratio) on the transmission
line.
Refer
to figure
3 for location of the output
connector and interconnecting data.
-3
ae
errpae
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