Flatness Control; Figure 3-5 Flatness Controls - Motorola STARLINE SERIES Installation And Operation Manual

3-8 Amplifier Setup

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
Forward
equalizer or
Cable simulator
(SFE-*-* or SCS-*)
Return
equalizer
(SRE-*-*)
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.
MB*/* Installation and Operation Manual
Bode C118
board
Manual
level
C116 (MAN)
SFE-*-*
460246-001
DRIVE UNIT/MAN ADU
Drive or TDU level (ADU)
control
select jumper
MDR
ADU
pad
(JXP
ADU)
DC/*
Auto