Data Sheet

ManualsBrandsUBS-Axcera ManualsElectronics6000-Watt UHF Transmitter

835A 4kW, 5kW or 6kW UHF Transmitter Detailed Alignment Procedure

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This Transmitter was aligned at the factory and should require no additional alignment to achieve normal operation. Check

that the RF Output at J2 of (A11) the Output Coupler Assembly of the Transmitter is terminated into a dummy load rated at

least at the output power of the Transmitter or is connected to the Antenna for your System. Refer to the Test Data Sheet for

your Transmitter and compare the final readings from the Factory with the readings on each of the Trays while doing the

alignment. They should be very close to the same. If a reading is way off, the problem is likely to be in that Tray.

Switch On the Main AC Circuit Breakers located on the AC Distribution Panels mounted toward the rear of each Cabinet.

Switch On CB2-CB4, for 4 kW, CB2-CB4 & CB5, for 5 kW & 6 kW and CB2-CB5 & CB6, for 6 kW. Circuit Breakers

located on each of the AC Distribution Assemblies in the Amplifier Cabinets.

This Transmitter contains a Receiver Tray and using the IF Relays, located on the ALC Board, give 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 is

accomplished by applying or removing a jumper on Jack J9 Pins 31 & 32 located on the Optional A/V Input and Remote

Interface Assembly or by applying or removing a jumper on Jack J11 Pins 10 & 28 located on the rear of the UHF Exciter. To

select the output from the Modulator, J9 Pins 31 and 32 or J11 Pins 10 & 28, must be connected together. To select the output

from the Receiver Tray, J9 Pins 31 and 32 or J11 Pins 10 & 28, must not be connected together.

(A3) UHF Receiver Tray (Optional)

Connect a UHF Input (-61 dBm to -16 dBm), with a Multiburst Test signal applied, that is at the desired Channel Frequency to

Jack J18, "F" type connector, for 75Ω or Jack J1, "N" type connector, for 50Ω located on the A/V Input & Remote Interface

Panel. Check that the On/Off Circuit Breaker, located on the rear of the Tray, is On.

Check the Front Panel Sample Jack (J9) with a Frequency Counter. The signal should be at the needed frequency, check the

top of the Channel Oscillator Assembly for the actual frequency, to produce the IF Outputs.

(A1) UHF Exciter Tray

This Tray has adjustments for Video and Audio Modulation levels and other related parameters.

Preset the following switches and pots located in the UHF Exciter Tray:

(A5) Sync Tip Clamp/Modulator Board (1265-1302):

W1 on J5 to the Bypass position, bypassing the Delay Equalizer Board, if present.

W7 on J4 to the Clamp Enable position, Auto Clamp On.

(A8) ALC Board (1265-1305):

W3 on J6 to the ALC Auto position.

W4 on J8 to the Normal position.

W8 on J9 to the Normal position.

W9 on J27 to the 6 dB Pad Out position.

W10 on J28 to the 6 dB Pad Out position.

W1 on J4 to the Disable (Off) position, Linearity Correctors Off.

W11 on J29 to the Local Modulator Select Disable position.

Preset the following switches and pots located in the UHF Exciter Tray:

(A9) IF Phase Corrector Board (1227-1250):

W2 on J9 to the Phase Correction Enable Position.

W3 on J10 to the Amplitude Correction Disable Position.

Switch the Exciter to Auto/Manual Switch to Manual and the Operate/Standby Switch to Operate.

Summary of content (6 pages)

PAGE 1
835A 4kW, 5kW or 6kW UHF Transmitter Detailed Alignment Procedure This Transmitter was aligned at the factory and should require no additional alignment to achieve normal operation. Check that the RF Output at J2 of (A11) the Output Coupler Assembly of the Transmitter is terminated into a dummy load rated at least at the output power of the Transmitter or is connected to the Antenna for your System.
PAGE 2
835A 4kW, 5kW or 6kW UHF Transmitter Detailed Alignment Procedure (A1) UHF Exciter Tray - Continued Connect an NTSC Composite Video Test Signal Input (1 Vpk-pk) to the Transmitter Video Input Jack J2, located on (A9) the Remote Interface Assembly. Connect a Baseband Audio Input (+10 dBm) to the Balanced Audio Input Terminal Block TB1 or if Stereo/Composite Audio Input (1 Vpk-pk) is provided, connect it to the BNC Jack (J6) the Composite Audio Input Jack.
PAGE 3
835A 4kW, 5kW or 6kW UHF Transmitter Detailed Alignment Procedure Phase and Gain Adjustment Procedure for the Transmitter This Transmitter was aligned at the factory for proper Phase and Gain and should require no additional alignment to achieve normal operation. Use this procedure only if a UHF Amplifier Tray has been replaced or repaired and full transmitter adjustment is needed.
PAGE 4
835A 4kW, 5kW or 6kW UHF Transmitter Detailed Alignment Procedure Phase and Gain Adjustment Procedure for the entire Amplifier Array Assembly 1. Begin the alignment with all Amplifier Trays up and running. Monitor the Reject Power by setting the Combined Metering switch to the Reject position and adjusting the Phase Control on either, or both, of the Phase/Gain Modules to minimize the Reject reading. 2. Adjust the Amplifier Gain controls so that all amplifiers have equal output power. 3.
PAGE 5
835A 4kW, 5kW or 6kW UHF Transmitter Detailed Alignment Procedure Calibration of the Reflected Output Level of the Transmitter Turn the Power Adjust Pot on the UHF Exciter to 20% on the Metering Panel Combined Meter in the Visual Power position, check that the Jumper is in Manual on the UHF Upconverter Board (1265-1310) in the UHF Exciter.
PAGE 6
835A 4kW, 5kW or 6kW UHF Transmitter Detailed Alignment Procedure (A10) Output Trap Filter Assembly - Continued The Trap Sections have been factory tuned and should not need major adjustments. The Frequency, relative to Visual Carrier, that the Trap is tuned to is marked on the Notch. Fine Tuning of the Notches Center Frequency can be accomplished with the Tuning Bolts located on the side of the Filter Section.