Operating instructions

3-8 Amplifier Setup

MB*/* Installation and Operation Manual

Flatness Control

All amplifiers are pre-aligned for optimal station flatness for the slope value ordered therefore,

there is usually no need to adjust the MDR board. However, you can make minor adjustments, if

necessary to achieve flatness across the passband.

The MDR-*MB/*/II board includes flatness controls and a fixed cable equalizer for 750 MHz or

870 MHz. This equalizer, plus the contribution of the hybrid gain stages, produces

approximately the dB of slope indicated by the model number (12 dB of tilt with an

MDR-*MB/12/II).

Adjust the MDR-*MB/*/II board and trimmer capacitors C116 and C118 on the main board to

correct peak-to-valley response variations. Figure 3-5 illustrates the location of the

MDR-*MB/*/II board and the two capacitors. Replace the equalizer if the response exhibits tilt.

Figure 3-5

Flatness controls

uto

level (ADU)

ADU

or TDU

Bode

board

C116

C118

Manual

level

(MAN)

ADU

pad

(JXP

ADU)

Forward

equalizer or

Cable simulator

(SFE-*-* or SCS-*)

SFE-*-*

DC/*

460246-001

Return

equalizer

(SRE-*-*)

DRIVE UNIT/MAN

Drive

control

select jumper

You can adjust the variable resistors and capacitors on the MDR-*MB/*/II board to flatten the

response across the passband. Use C1, C2, C3, C4, C6, C7, R2, R3, R4, and R5 on the

MDR-*MB/*/II board (illustrated in Figure 3-6) to obtain a flat response.