User's Manual

Digital UHF Transmitter Chapter 2, System Description and
Customer Remote Connections
DT835A, Rev. 1 2-8
2.1.12 Main AC Input
The transmitter needs an AC input of
208/240 VAC at 100 amps for each
amplifier array assembly and at 20 amps
for the exciter assembly.
The 208/240 VAC input to each amplifier
assembly connects to (A10) the AC
distribution assembly, amplifier array
(1278-1200), on the right, center of
each cabinet. The assembly contains the
terminal block (TB1) that connects to
the 208/240 VAC. Line 1 is connected to
TB1-1A, line 2 to TB1-3A, and safety
ground to TB1-4A.
The distribution assembly contains nine
circuit breakers that supply the AC to
the rest of the amplifier assembly. The
input AC from TB1 is connected to (CB1)
the main AC circuit breaker (100 amps)
that distributes the 208/240 VAC to the
other eight circuit breakers. The output
of CB1 has three MOVs, VR3, VR4, and
VR6, mounted to it: VR4 is connected
from line 1 to ground, VR6 is connected
from line 2 to ground and VR3 is
mounted across the two lines. The
switched input AC is wired through the
six circuit breakers, CB2-CB7, to the six
UHF amplifier trays in the amplifier
cabinets. CB2 is a 20-amp circuit
breaker that supplies the AC voltage to
the (A1) UHF amplifier tray. CB3 is a 20-
amp circuit breaker that supplies the AC
voltage to the (A2) UHF amplifier tray.
CB4 is a 20-amp circuit breaker that
supplies the AC voltage to the (A3) UHF
amplifier tray. CB5 is a 20-amp circuit
breaker that supplies the AC voltage to
the (A4) UHF amplifier tray. CB6 is a 20-
amp circuit breaker that supplies the AC
voltage to the (A5) UHF amplifier tray.
CB7 is a 20-amp circuit breaker that
supplies the AC voltage to the (A6) UHF
amplifier tray. The circuit breakers CB8
and CB9 control the AC to the A12-A3
and A12-A5 fans mounted on the
(optional) (A12) reject load assembly
that only used as part of the 2.5 and 3
kW amplifier array assemblies.
The 208/240 VAC input to the single
UHF exciter assembly connects to (A8)
the AC distribution assembly, single UHF
exciter assembly (1245-1500), in the
right, center rear of the cabinet. The
assembly contains the terminal block
(TB1) that connects to the 208/240
VAC. Line 1 is connected to TB1-1A, line
2 to TB1-3A, and ground to TB1-2A. The
AC distribution panel contains (CB1) the
main circuit breaker (20 amps) that
supplies the AC to the rest of the single
exciter assembly. The output of CB1 has
three MOVs, VR1, VR2, and VR3,
connected to it: VR1 from line 1 to
ground, VR3 from Line 2 to ground and
VR2 across the two lines. The AC output
of CB1 connects to A1 and A2, the IEC
outlet strips, into which the external
trays connect. The (A1) UHF exciter tray
and the (A4) variable phase/gain tray
plug into the (A1) IEC outlet strip. The
(A5) variable phase/gain tray, the (A6)
metering panel, the (optional) (A7)
receiver tray, the 8 VSB modulator tray
or other optional trays plug into the (A2)
IEC outlet strip. When the circuit
breaker CB1 on the single UHF exciter
assembly is switched on, +12 VDC from
the UHF exciter tray is supplied to each
of the amplifier array cabinets. The +12
VDC is split six ways in the amplifier
array and connected to each of the UHF
amplifier trays to operate the LED status
indicators in the tray. Also +12V is
connected to the (Optional) external
exhaust kit, if present.
2.1.13 Customer Remote Interface
Connections
The remote monitoring and operation of
the transmitter is provided through the
jacks (J8, J9, and J10) on (A9) the
remote interface assembly mounted on
the rear of the single UHF exciter
assembly (see Figure 2-1).