User's Manual

8 3 6 A 2 k W UHF Tr a nslat or , I nt erna lly Diple x ed Det ailed Alignm e n t Pr oce dur e

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This Translat or was aligned at the factory and should require no addit ional alignm ent t o achieve

norm al operat ion.

Check t hat the RF Out put at J2 of ( A16) t he Coupler of the Translator is t erm inat ed int o a dum m y

load of at least 2000 Wat t s. Refer to t he Test Dat a Sheet for your Translator and com pare the

final readings from the Factory wit h the readings on each of the Trays while doing t he alignm ent .

They should be very close t o t he sam e. I f a reading is way off, t he problem is likely t o be in that

Tray.

Switch On t he Main AC and the UHF Excit er Circuit Breakers locat ed on the AC Dist ribut ion Panel

m ounted behind the rear Cabinet door.

( A3 ) VH F/ UHF Re ce ive r Tray ( 1 2 6 5 - 1 1 0 0 )

Connect a UHF I nput ( - 61 dBm t o - 16 dBm ) , w it h a Multiburst Test signal applied, that is at t he On

Channel Frequency t o Jack J5, " F" type connector for 75Ω or Jack J1, "N" t ype connect or for 50Ω

located on t he Receiver Tray. Check t hat t he On/ Off Circuit Breaker, locat ed on the rear of the

Receiver Tray, is On. I f the Opt ional Rem ot e Pream plifier is purchased, t he Fuse F1 locat ed in the

Receiver Tray m ust be rem oved t o elim inate the + 12 VDC from t he input t o the Receiver Tray t o

prevent dam age t o t he Test equipm ent. Check t he Front Panel Sam ple Jack ( J6) with a Frequency

Count er. The signal should be at t he needed frequency, check t he t op of the Channel Oscillat or

Assem bly for t he act ual frequency, to produce t he I F Out puts.

( A4 ) UHF Excit er Tr a y ( 1 3 0 0 - 1 0 2 0 )

The I F Section of the UHF Excit er Tray includes adj ust m ent s for autom at ic level cont rol (ALC) ,

linearit y ( am plit ude predist ortion) and phase (phase change vs. level) predistort ion for correct ion

of the nonlinearit ies of the RF Am plifier Trays. The Upconverter Sect ion also includes adj ust m ents

of the local oscillat or chain t uning and also the local oscillat or center frequency tuning. Bot h of

these were com plet ed at the factory and should not require adjust m ent at t his t im e.

Move the Operat e/ Standby Swit ch locat ed on the UHF Excit er Tray t o Standby. The set up of the

RF Out put, includes adj ust m ent of t he drive level to the four UHF Am plifier Trays, t he adj ustm ent

of the Linearit y and Phase Predistortion which com pensat e for any nonlinear response of the

Am plifier Trays and also t he gain and phasing adj ust m ent s of the four UHF Am plifier Trays.

Verify t hat all Red LEDs locat ed on the ALC Board are ext inguished. The following list details the

m eaning of each LED when illum inated.

DS1 ( I nput Fault ) I ndicat es abnorm ally low or no I F is present at t he I nput of t he ALC Board.

DS2 ( ALC Fault ) I ndicat es t hat the ALC circuit is unable t o m aint ain t he signal level request ed by

the ALC reference. Norm ally t his is due t o excessive att enuation in t he linearit y signal path, t he I F

Phase correct or signal pat h or t hat Jum per W3 on J6 is in the Manual ALC Gain position.

DS3 ( Video Loss) I ndicat es a loss of Video at t he I nput of the ALC Board.

DS4 ( Mut e) I ndicat es a Visual Mut e Com m and is present . Not use d in t h is configurat ion.

DS5 ( Modulat or Enable) I ndicat es Modulat or I F Output is selected. Will be Off if the out put of the

Receiver Tray is select ed.

The ALC is Muted when the Translat or is in St andby. To m onit or t he ALC, t urn Off t he front panel

On/ Off circuit breaker locat ed on the Am plifier Trays and swit ch t he Translator t o Operat e. Adj ust