User's Manual

Digital UHF Transmitter Chapter 3, Installation and Setup Procedures
DT835A, Rev. 1 3-6
3. Verify that the circuit breaker (CB1),
located on the rear of the tray, and
the main circuit breaker for the
system are off.
4. Connect the AC power cord, provided
in the installation kit, to J1, the AC
input jack on the rear of the tray.
5. Connect the MPEG input to J2, the IF
output from J4, and the 10 MHz
reference input, if supplied, to J3 on
the rear of the tray.
6. Connect the IF output at J4 to the
digital IF input to the upconverter of
the system.
This completes the installation procedure
for the DM8-R modulator.
3.4 Main AC Inputs
Once the cabinets are in place, and the
trays have been checked for damage and
alignment, the main AC hookup is ready
to be made.
Caution: Before connecting the
208/240 VAC, make certain that all
of the circuit breakers associated
with the transmitter are switched
off.
There are three AC input circuits to the
DT835A transmitter: one is 20 amps and
the two others are 100 amps single
phase. The input AC to the exciter
cabinet should be a 20 amp, 208/240
VAC line. The input AC to each amplifier
cabinet should be a single-phase, 100
amp, 208/240 VAC line.
The 20-amp, 208/240 VAC input
connections are made to the terminal
block A1-TB1, part of the AC distribution
assembly, exciter cabinet (1245-1500),
near the center, right-hand side, rear
portion of cabinet #1. Connect terminal 1
to line 1, terminal 3 to line 2 (208/240
VAC), and terminal 2 to the chassis
ground.
For single phase - Connect one of the
100-amp, 208/240 VAC inputs to the
terminal block A3-TB1, part of the AC
distribution assembly, amplifier
assembly (1278-1100), near the center,
right-hand side, rear portion of cabinet
#2. Connect line 1 to TB1-1A, line 2 to
TB1-3A and the safety ground to TB1-
4A. Follow the same procedure for
cabinet #3.
3.5 Output Connections
The RF output of the (A2) amplifier
assembly connects through (A5) a 1-5/8"
to 3-1/8" adapter to J1 on (A4) the
hybrid combiner. The RF output of the
(A3) amplifier assembly connects
through (A6) a 1-5/8" to 3-1/8" adapter
to J2 on (A4) the hybrid combiner. The
reject output of the combiner at J4
connects through (A12) a 1-5/8” to 3-
1/8” adapter to (A7) a directional coupler
(1016-1043) and then to (A8) the 2500-
watt reject load. The combined RF output
of the combiner at J3 connects through
(A9) the bandpass filter to (A10) the
output trap filter assembly. The filtered
output connects through (A11) the
output coupler assembly (1020-1002) to
the transmission line that is connected to
the antenna.
This completes the unpacking and
installation procedures for the DT835A
transmitter. Refer to the setup and
operation procedures that follow before
applying power to the transmitter.