Data Sheet Chapter 5

4-6 kW UHF Translator Chapter 5, Detailed Alignment Procedures
837B, Rev. 0 5-16
to the RF Input (J1) of the amplifier.
Re-adjust the Phase to peak the
System output power. If the Phase
Control again reaches its end of
travel before a peak in power is
reached, remove the 2 inch cable
and add a 3 inch cable to J1 of
amplifier and readjust phase for
peak output power. The adding of
cables should be done during the
adjustment anytime the range of
the phase adjust needs extended.
7. Repeat steps 5 and 6 for the
remaining Amplifiers.
8. Increase the output power on
Amplifier #1 and Amplifier #2 to
90%.
9. Adjust the Phase Control on
Amplifier #2 to peak the System
output power.
10. Increase the output power on
Amplifier #3 to 90% and adjust the
Phase control for maximum System
output power.
11. Increase the output power on
Amplifier #4 to 90% and adjust the
Phase control for maximum System
output power.
12. Increase the output power on
Amplifier #5, if present, to 90%
and adjust the Phase control for
maximum System output power.
13. Increase the output power on
Amplifier #6, if present, to 90%
and adjust the Phase control for
maximum System output power.
14. Monitor the Reflected Power on all
of the UHF Amplifier Trays. The
Reflected Power should read <5%.
If an amplifier is showing high
reflected power adjust the Phase
control to minimize Reflected
Power. Be careful not to increase
Reflected Power on the other
Amplifier Trays. The Amplifier
Trays should interact in such a way
that the phasing of any one
Amplifier will affect the Reflected on
the other Amplifiers.
5.6 Calibration of the Side A and Side
B Amplifier Arrays Forward Output
Power Level
Note: Perform the following
procedure only if the power
calibration is suspect.
Perform the following adjustments with
no aural present by removing jumper
cable W1, the aural IF loop-through that
is connected to J16 on (A5) the sync tip
clamp/modulator board. Connect a sync
and black test signal to the video input
jack of the UHF exciter tray. Switch the
translator to Operate.
Next, set up the translator for the
appropriate average output power level:
• Sync + black 0 IRE setup/wattmeter
= (1309 watts for 4kW) or (1636
watts for 5kW) or (1964 watts for
6kW)
• Sync + black 7.5 IRE
setup/wattmeter = (1200 watts for
4kW) or (1499 watts for 5kW) or
(1799 watts for 6kW)
(2200 Watts peak of sync Visual + 10%
Aural for 4 kW transmitter), or (2750
Watts peak of sync Visual + 10% Aural
for 5 kW transmitter) or (3300 Watts
peak of sync Visual + 10% Aural for 6
kW transmitter)
Note: The translator must have 40
IRE units of sync.
With the spectrum analyzer set to zero
span mode, obtain a peak reference on
the screen. Reconnect jumper cable W1
to J16 on (A5) the sync tip clamp/
modulator board. Turn the gain adjust
pot, located on the front panel of the
Phase/Gain Tray, until the original peak
reference level is attained.