Assembly Instructions Chapter 4

4-6 kW UHF Translator Chapter 4, Circuit Descriptions
837B, Rev. 0 4-37
Interface Panel located in the Amplifier
Array Assembly. The RF is cabled to
the COM Input of (A9-A1) the 8 Way
Splitter that splits it eight ways. Four,
five or six of the RF outputs (+6 dBm)
of the Splitter are connected to J1, the
RF Input Jack on each of the four, five
or six UHF Amplifier Trays. The outputs
of the Splitter that are not used are
terminated with 50. Each of the UHF
Amplifier Trays amplify the RF signals
to approximately (+60 dBm), which is
the power needed to produce a total of
4000 - 6000 Watts Peak of Sync after
combining of the two Amplifier
Assemblies, with a maximum of 600
Watts Peak of Sync output per Tray.
The outputs of the UHF Amplifier Trays
are combined in the (A7) 4, 5 or 6 Way
Combiner. The Reject Output of the
Combiner is connected to (A12) the
Reject Load Assembly (Only in 5 or 6
kW transmitters).
The RF Output of the Combiner is
connected to (A8) the Output Coupler
Assembly which supplies a Forward
and a Reflected Power Sample of the
output from the Amplifier Assembly
that connect through the SMA
Connectors J2 and J3 located on the
(A11) Interface Panel to the Metering
Panel located in the UHF Exciter
Assembly.
The RF output of the Amplifier Array
(+63.5 to +65.2 dBm) is at J2 (1-5/8”)
of the Output Coupler.
In each UHF Amplifier Tray, a Forward
Power Sample and a Reflected Power
Sample, from the 4 Way Combiner
Board, are connected to the Dual Peak
Detector Board, Single Supply. The
Dual Peak Detector provides peak
detected forward samples to the
Amplifier Control Board that supplies
the samples to the front panel meter of
the UHF Amplifier Tray and also to the
Interface Panel for remote monitoring.
Before exiting each UHF Amplifier Tray
the RF is fed through a Circulator which
protects the Tray from high VSWR
conditions. The Reject Port of the
Circulator provides a Reject Sample to
the 4 Way Combiner Board which
supplies the Reflected Sample to the
Dual Peak Detector Board, Single
Supply located in the UHF Amplifier
Tray that connects to the front panel
meter.
The two power supply Enable (Operate)
Commands from the UHF Exciter Tray,
located in the UHF Exciter Assembly,
connect to the Terminal Block (A9-TB2)
mounted in each Amplifier Array. The
terminal block splits the Enables fur,
five or six ways in each array and
supplies them to all of the UHF
Amplifier Trays. The Enable is needed
to turn on the Switching Power Supply
located in each UHF Amplifier Tray. If
the Amplifier Array contains an
(Optional) External Exhaust Kit, then a
Fan Enable is supplied at J4-19 along
with +12V at J4-20 that connect to the
fan mounted on the roof, which turns it
on.
Main AC Input
Each Amplifier Assembly needs an AC
Input of 208/240 VAC at 55 Amps three
phase or 100 Amps Single Phase wired
to it. The 208/240 VAC Input to each
Amplifier Assembly connects to (A10)
the AC Distribution Assembly, Amplifier
Array (1278-1100 three phase or 1278-
1200 single phase) located on the right
side, center rear of each Cabinet. Each
AC Distribution Assembly contains the
Terminal Block (TB1) to which the
208/240 VAC connects.
For three phase, connect Line 1 to TB1-
1A, Line 2 to TB1-2A, Line 3 to TB1-3A
and Ground to TB1-4A. The AC
Distribution Panel contains 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 (55 Amps) that
distributes the 220 VAC to the other
circuit breakers (CB2-CB9). The output
of CB1 has six MOVs for protection,
VR1 from Line 1 to Line 2, VR2 from