User's Manual

300-Watt Digital UHF Transmitter Chapter 3, Installation and Setup Procedures
DT830A, Rev. 1 3-5
Caution: Each UHF amplifier tray has
a hardline coaxial cable connected to
the bottom panel. The tray will not
slide out unless this cable is first
removed. To pull the tray out for test
purposes, use the extender coaxial
cable included in the installation
material kit for connections from the
tray to the output cable.
Adjustments to the position of the trays
may be necessary. To accomplish this,
loosen the cabinet slide mounting bolts
that hold the front of the slide to the
mounting frame of the cabinet and move
the tray up or down as needed to correct
for the rubbing.
The air intake to the transmitter is
intended for room air only. The cabinet
should be positioned with consideration
given to adequate air intake and exhaust,
the opening of the rear door, access to
the trays (including sliding them out for
testing), the main AC hookup, and the
installation of the output transmission
line. The cabinet should be grounded
using copper strapping material and
should also be permanently mounted to
the floor of the site using the holes in the
bottom of the cabinet.
3.3 Installation of the Cabinets and
Trays
Once the cabinet is in place and the trays
are checked for damage, the main AC
hookup is ready to be made.
Caution: Before connecting the 230
VAC, make certain that all of the
circuit breakers associated with the
transmitter are switched off.
The main AC input circuit to the
transmitter should be a 40-amp, 80-amp
for upgradeable version, 230-VAC line,
using AWG 8 wire inside of a 1-1/4"
conduit. The 230-VAC input connections
(terminals 1 and 2 [230 VAC] and
terminal 3 [chassis ground]) are made to
terminal block TB1, which is part of (A2)
the AC distribution panel near the rear
door of the transmitter. Line 2 is the
neutral for international systems using
220 VAC hot and neutral.
The RF output at J2 of (A11) the coupler
assembly, which is 7/8" rigid coax,
should connect to the transmission line
that is connected to the antenna system.
The MPEG digital source input connects
to J3, ECL, or TTL, depending on the
configuration, at the rear panel of (A19)
the modulator or J2 on (A12) the remote
interface panel. Remote functions
connect to the rear of (A4) the UHF
exciter or to (A12) the input and remote
interface panel mounted on the rear top
of the transmitter. A plug is connected to
jack J11 with pins 23 and 24 jumpered
together on the UHF exciter or to jack J9
with pins 21 and 22 jumpered together
on the (optional) remote interface panel.
These are 37-pin, “D”-connectors that
provide the interlock for the transmitter.
Jacks J10 and J11 on the UHF exciter,
and jacks J9 and J10 on the (optional)
remote interface panel, are used to
connect the remote control functions to
the transmitter.
This completes the unpacking and
installation procedures for the DT830A
Digital UHF Transmitter. Refer to the
setup and operation procedures that
follow before applying power to the
transmitter.
3.4 Setup and Operation Procedures
The transmitter should initially be turned
on with the RF output of the bandpass
filter/coupler assembly terminated into a
dummy load of at least 500 watts. If a
load is not available, check that the
output of the coupler assembly is
connected to the antenna.
Switch on the main AC, UHF exciter,
digital modulator, and the amplifier #1
and #2, amplifier #3 and #4 are used
after upgrade, circuit breakers located on
the AC distribution panel facing the rear