Operating instructions

3-14 Amplifier Setup
MB*/* Installation and Operation Manual
Thermal Drive Unit
The TDU senses temperature and controls the Bode board. It is assumed that the cable is
subjected to the same or similar temperature; therefore, the TDU should not be used for
underground installations.
To set-up the TDU:
1 Place the jumper on the TDU (Figure 3-9) to the LOW, MEDIUM, or HIGH position. This setting
specifies the amount of cable for which the TDU compensates at the highest frequency
preceding the MB*/* station. Low = 0 dB to 15 dB of cable, medium = 15 dB to 30 dB of
cable, and high = 30 dB or more of cable.
Figure 3-9
TDU cable selector
Low
Medium
Thermal
level
High
2 Position the drive control select jumper (Figure 2-15) temporarily in the MAN position and
perform the complete procedure described in Manual Gain Control if not already completed.
3 Position the drive control select jumper to DRIVE UNIT.
4 Connect a signal-level meter to the FWD OUT test point and tune the meter to the high
band-edge carrier.
5 Turn the thermal level potentiometer on the TDU fully clockwise and then reduce to obtain
the level obtained in Step 9 under Manual Gain Control.