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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- 4.5 MHz and + 9 MHz from F

at t he top and bot t om respectively of the left hand side of the

Bandpass Filt er, looking from the rear of t he Cabinet. Refer to t he Bandpass Filter Drawing for t he

location of the adj ust m ent s.

To tune t he filter, connect a sweep signal t o t he input of the filt er and adj ust the five t uning bolts

for a 6 MHz bandwidt h and a flat frequency response across t he desired band. N ote: The

Bandpass Ripple should be ≤0.25 dB. The 6 MHz Band should also have a m inim um of 20 dB ret urn

loss across the pass band.

Refer t o t he Table below for t ypical values.

Frequency I nse r t ion Loss ( dB) Re t u r n Loss ( dB)

- 4.5 ≥35

- 0.5 ≥20

≤0.6 ≥20

+ 8.08 ≥15

- 9 ≥30

≥30

( Optiona l) ( A1 4 ) On e or Tw o Sect ion Trap Filter

The Trap Sect ions have been fact ory tuned and should not need m aj or adj ustm ent s. The Trap

Filt er is Opt ional and m ay not be part of your Syst em . The input t o the One or Two Section Trap

Filt er is t he out put of t he Coupler Assem bly. The Trap Filt er is com prised of 3- 1/ 8" EI A standard

transm ission line sections connect ed t o t he m ain t ransm ission line. The transm ission line assem bly

consist s of 7/ 8" EI A standard rigid coaxial com ponents.

The Traps on the output Trap Filter are labeled wit h t heir Cent er Frequency relat ive to t he

Frequency of the Carrier. ( For Exam ple: The Traps labeled - 4.5 MHz are tuned for a Cent er

Frequency of 4.5 MHz Lower t han the Frequency of the Visual Carrier.)

The Trap Sect ions are Reflect ive Not ches, adj ust able across the ent ire UHF Frequency Band. The

elect rical lengt h of the Out er Sleeve and the Cent er Rod of the Not ch can be adj ust ed t o Tune the

Not ch Frequency. The Dept h of t he Not ch is set by t he gap between the Center Conduct or of the

Trap Section and the Cent er Conduct or of t he Main Line. Tight Coupling m akes a Deep Notch,

while Loose Coupling m akes a Shallow Not ch.

Fine Tuning, of the Notches Cent er Frequency can be accom plished with the Tuning Bolt s locat ed

on the side of the Filt er Section. Loosen t he nut locking the Bolt in place and adj ust t he Bolt t o

change t he Frequency of the Not ch. Monit or t he output of t he Translat or wit h a Spectrum

Analyzer and Null the Distortion Product with the Bolt. Red Field is a good Video Test Signal to use

to see t he + 8.08 MHz Product . Tighten the nut when t he tuning is com pleted. Hold the bolt in

place wit h a screwdriver as the nut is t ight ened t o prevent it from slipping.

Ma j or Tun in g, such as changing the Not ch Dept h or m oving the Not ch Frequency m ore t han 1

MHz, the Out er Conduct or and t he Cent er Conduct or of t he Trap Section m ust bot h be m oved.

This requires an RF Sweep Generator t o accom plish. Apply the Sweep signal t o t he I nput of t he

Trap Filt er and m onit or t he Out put . Loosen t he Clam p holding the Out er Conduct or in place and

m ake t he length longer to Lower t he frequency of the Not ch or short er t o Raise t he frequency of

the Not ch. Loosen the Cent er Conduct or wit h an Allen Wrench and m ove it Deeper for a Lower

Frequency Notch or out for a Higher Frequency Not ch. These adj ust m ents m ust bot h be m ade to

change t he Not ch Frequency. Moving only the Center Conduct or or t he Outer Conduct or w ill

effect t he Not ch Dept h in addit ion t o t he Center Frequency. The variable that is being adj usted