UBS Axcera 835A-6 6000-Watt UHF Transmitter User Manual 281871

UBS-Axcera 6000-Watt UHF Transmitter 281871

Operation Procedure

835A 4 kW, 5 kW or 6 kW UHF Transmitter Set Up and Operation Procedure
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Initially the Transmitter should be turned on with the RF Output at J2 of the (A11) Coupler Assembly terminated into a
dummy load of at least the power rating of the Transmitter. If a load is not available, check that the Output of the Coupler
Assembly at J2 is connected to the Antenna for your System.
If your Transmitter contains the Receiver Option, it provides the operator the ability to select either the Combined IF Output
from the Receiver Tray or from the Modulator. The switching of the IF Relay, located on the ALC Board, is accomplished by
applying or removing a jumper on Jack J8 Pins 10 & 11 located on (A9) the Remote Interface Assembly. 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.
Connect the On Channel RF Signal Input to the "N" Connector Jack (J1), for 50Ω Input, or to the "F" Connector Jack (J3), for
75Ω Input, located on (A9) the Remote Interface Assembly, mounted on the top, rear of the cabinet. With Receiver selected,
the Transmitter uses the IF Output from the Receiver Tray.
Connect the Baseband Balanced Audio Input to the Terminal Block (TB1) located on (A9) the Remote Interface Assembly,
mounted on the top, rear of the Single UHF Exciter Cabinet. If Composite Audio, Stereo, is used instead of Balanced Audio,
connect the Composite Audio Input to the BNC Jack (J6). Connect the Baseband Video Input to the BNC Jack (J2) also
located on (A9) the Remote Interface Assembly.
Switch On the Main AC Circuit Breaker located on the AC Distribution Assembly mounted toward the rear of the Single UHF
Exciter Assembly. Switch On the Main AC Circuit Breakers located on the AC Distribution Assemblies mounted toward the
rear of the Amplifier Cabinets. Switch On the CB2-CB6 Circuit Breakers, for the individual UHF Amplifier Trays, on the AC
Distribution Assemblies mounted in each Amplifier Cabinet.
Switch the Operate/Standby Switch located on the UHF Exciter to Standby and the Auto/Manual Switch also on the UHF
Exciter to Auto. Normal operation of the Transmitter is with the switch in Automatic. Automatic operation of the Exciter uses
the Video Input to the Exciter as an Operate/Standby Switch. In Auto, if the Input Video is lost, the Exciter will automatically
revert the Transmitter to Standby and when the Video Signal is restored, the Exciter will automatically return the Transmitter
to Operate.
Move the Operate/Standby Switch on the Exciter to Operate. Note the power supply readings on the front panel Meters of the
UHF Amplifier Trays in each Amplifier Cabinet Assembly, they should be +26.5 VDC. Note: If the Transmitter does not
switch to Operate, when the Operate/Standby Switch is switched to Operate, check that there is an External Interlock Plug
connected to Jack (J7), located on the Remote Interface Assembly mounted in the top, rear of the Single UHF Exciter Cabinet,
and that it has a Jumper from Pins 1 to 2 which provides the interlock for the Exciter. The Interlock must be present for the
Transmitter to Operate.
Observe the Front Panel Meter located on the Metering Panel with the switch in the Combined Visual Output Power position,
it should read 100%. If needed, adjust the Power Adjust screwdriver pot located on the front panel of the UHF Exciter to
attain 100% Output on the Front Panel Meter located on the Metering Panel with the switch in the Combined Visual Output
Power position.
As you are checking the output Power Level, check the Meter Readings on the Transmitter Metering Panel in the % Reflected
Power Position for the Side A and also the Side B Amplifier Assemblies and the Combined position for the Transmitter. If the
% Reflected Power for any of the readings is very high, above 20%, a problem with the Output Coaxial Lines in the problem
Side Amplifier Assembly or in the Output Lines for the System is present and needs to be checked and corrected. A center
bullet missing from the 1-5/8" or 3-1/8" Rigid Coax Lines or loose bolts on the connections can cause this problem. Return the
Operate/Standby Switch to Standby.
Observe the % Exciter Power reading of the Meter on the Exciter, it should read the same as written on the Test Data Sheet for
your Transmitter. Move the Operate/Standby Switch, located on the Exciter, to Standby.
The Gain and Phase controls located on the front panels of the individual UHF Amplifier Trays were adjusted at the factory to
attain 100% Output of the Transmitter and should not need readjusted. The Forward Meter readings for Side A and for Side B
may not be the same but should be the same as the values written on the Test Data Sheet for your Transmitter. Side A and Side
B are combined to give the correct Peak of Sync Output, which is 100% in the Combined Visual position.
835A 4 kW, 5 kW or 6 kW UHF Transmitter Set Up and Operation Procedure
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The readings on each of the individual UHF Amplifier Trays may not be the same. Refer to the Test Data Sheet for your
Transmitter and compare the final readings from the Factory on the Test Data Sheet with the readings on each of the Trays
after the Set Up. They should be very close to the same. If a reading is way off, refer to the Phasing and Power Adjustment
Procedure for the UHF Amplifier Trays in the Detailed Alignment Procedure before trying to adjust.
If a dummy load is connected to the Transmitter, switch the Transmitter to Standby and switch Off the Main AC Circuit
Breakers found on the AC Distribution Panels in each Cabinet. Remove the dummy load and make all connections needed to
connect the Transmitter to the Antenna for your System. Switch the Main AC Circuit Breakers On and the Operate/Standby
Switch to Operate. Adjust the Exciter Power Adjust pot to attain 100% Combined Output.
If the Transmitter is already connected to the Antenna, check that the Combined Output is 100%. If needed, adjust the Power
Adjust Pot located on the UHF Exciter for 100% in the Combined Output position.
This completes the Transmitter Set-Up and Operation Procedure for the 835A Transmitter. The Transmitter can now be
Operated normally. For Normal operation the Exciter should be in Operate and the Auto/Manual Switch should be in Auto.
If a problem occurred during the Set-Up and Operation Procedure refer to the Detailed Alignment Procedure of the Transmitter
for more information.

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