System Description Chapter 2

4-6 kW UHF Translator Chapter 2, System Description
837B, Rev. 0 2-1
Chapter 2
System Description
The 837B is a complete 4-6 kW UHF Solid
State Internally Diplexed Television
Translator which operates at a nominal
Visual Output Power of 4000 - 6000
Watts Peak of Sync and Average Aural
Output Power of 400 - 600 Watts, at an
A/V Ratio of 10 dB, 10 % Sound or 200 -
300 Watts at 13 dB, 5 % Sound. The
837B is made up of three Cabinets, a
UHF Single Exciter Cabinet and two
Amplifier Array Cabinets.
2.1 System Overview
The standard 837B is functionally
comprised of (A1) a Single UHF Exciter
Assembly, (A2 & A3) two 2-3 kW
Amplifier Array Assemblies, (A4) a Hybrid
Combiner Assembly and (A11) an Output
Coupler Assembly. A sample is taken
from the Hybrid Combiner and connected
to (A7) a Directional Coupler.
2.1.1 (A1) UHF Exciter Assembly
(1278-1400; Appendix C)
The (A1) UHF Exciter Assembly is made
up of the trays and assemblies listed in
Table 2-1.
Table 2-1. UHF Exciter Assembly Trays and Assemblies
MAJOR ASSEMBLY
DESIGNATOR
TRAY/ASSEMBLY NAME PART NUMBER
A1 UHF Exciter, M/N 1142458
A3 2-way splitter assembly ZSFC-2-2SMA
A4 Phase/Gain Tray 1245-1200
A5 Phase/Gain Tray 1245-1200
A6 Metering Panel 1136811
A7 UHF receiver tray 1265-1100
A8 AC Distribution Assembly 1245-1500
A9 Remote Interface Assembly 1245-1801
The UHF Exciter Tray operates using
either the IF Output from the (A7) UHF
Receiver Tray connected to J1 on the ALC
Board (1265-1305) or the Combined IF
Output generated from the (Optional)
Baseband Audio and Video Inputs
connected to J32 on the ALC Board. The
two IF Outputs are connected to the IF
Relays K3 and K4, located on the ALC
Board and by applying or removing a
Jumper on Jack J8 Pins 10 & 11 located
on (A9) the Remote Interface Assembly
(1245-1801) the IF Output is selected.
To select the output from the Modulator,
J8-10 and 11, must be connected
together. To select the output from the
Receiver Tray, J8-10 and 11, must not be
connected together.
The UHF Receiver Tray (1265-1100)
takes the received RF On Channel
Frequency and generates a 45.75 MHz +
41.25 MHz Combined IF Output. The
Combined IF Output of the Receiver Tray
connects to J6 on the rear of the (A1)
UHF Exciter that is wired to J1 on the ALC
Board. With Receiver selected, no
connection between J8-10 and 11 on the
Remote Interface Assembly, the IF
Output from the Receiver Tray connects
through the Relays to the rest of the ALC
Board.
The (Optional) Baseband Audio, from
TB1 or J3, and Video, from J1, connect
to the UHF Exciter which produces a
Combined IF Output that connects to
J32 on the ALC Board.