Data Sheet Chapter 5

4-6 kW UHF Translator Chapter 5, Detailed Alignment Procedures
837B, Rev. 0 5-13
frequencies must be minimized to
prevent interference with other channels.
While monitoring each test point with a
DC voltmeter, maximize each test point
by tuning the broadband multipliers in
the following sequence:
• Monitor TP1 with a DVM and tune C4
for maximum (typical 0.6 VDC).
• Monitor TP2 and tune C6 and C10 for
maximum (typical 1.2 VDC).
• Monitor TP3 and tune C12 and C18
for maximum (typical 2.0 VDC).
• Monitor TP4 and tune C20 for
maximum.
• Repeak C12 and C10 while
monitoring TP4 (typical 3.5 VDC).
• The typical output level is +15 dBm.
5.3.13 (A3) +12 VDC (4A)/-12 VDC
(1A) Power Supply Board (1265-
1312; Appendix D)
There are no adjustments that need to
be made to (A3) the +12 VDC (4A)/-12
VDC (1A) power supply board. DS1 will
be lit if a +12 VDC output is connected to
J6. DS2 will be lit if a +12 VDC output is
connected to J3. DS3 will be lit if a +12
VDC output is connected to J4. DS4 will
be lit if a +12 VDC output is connected to
J5. DS5 will be lit if a -12 VDC output is
connected to J7 and J8.
5.3.14 (A17) Transmitter Control
Board (1245-1101; Appendix D)
To align the video metering, insert a
composite or some other 100-IRE test
signal into the exciter tray. Adjust R20
for a full-scale reading (1 volt) on the
bottom scale of the front panel meter of
the exciter tray in the video metering
position.
To align the audio metering, adjust the
audio input level for a ±25 kHz deviation
using a spectrum analyzer. Adjust R19 on
the board for a 25-kHz reading on the
bottom scale of the front panel meter of
the exciter tray.
This completes the detailed alignment
procedures for the UHF exciter tray.
5.4 (A1, A2, A3 & A4 and A5(5kW) &
A6(6kW) UHF Amplifier Trays,
LDMOS (1301560, low
band/1301561, mid band/1301562,
high band; Appendix C)
The UHF amplifier trays have been
adjusted at the factory to meet all
specifications, including phase
adjustment, to match the multiple trays
in an amplifier array when they are
combined. The trays should not need to
be adjusted to attain normal operation.
Any adjustments to the boards in the
trays should be performed in the Manual
Gain position, with S1 on (A8) the
amplifier control board (1265-1414) in
Manual. The idling current for the
amplifier boards are adjusted with no RF
drive applied. S1 should be in the Auto
AGC position for the normal operation of
the translator.
Connect a dummy load with a rating of a
least 600 watts to J2, the “N” connector
RF output jack of the tray being tested.
5.4.1 (A2-A1) Variable Gain/Phase
Board (1301549; Appendix D)
The board is mounted in (A2) the
variable gain/phase enclosure. There are
no adjustments to this board; it has an
AGC adjustable gain of 0 to 20 dB.
Typically with an input of +3 dBm output
is set at +19 dBm.
5.4.2 (A3-A1) 1-Watt UHF Amplifier
Board (1301547; Appendix D)
The board is mounted in (A3) the 1-watt
UHF amplifier enclosure. There are no
adjustments to this board; it has
approximately 10 dB of gain.