Motorola BT100 - Manual (Page 35)

3-10 Amplifier Setup
BT100 Installation and Operation Manual
ƒ Low = channel 2 (55.25 MHz) or channel 3 (61.25 MHz)
ƒ If the tilt is less than required, install a higher value input equalizer
ƒ If the tilt is greater than required, install a lower value input equalizer
ƒ If the high value equalizer provides too much tilt and the low value equalizer provides
too little tilt, use the lower value equalizer. Under-equalization is preferred to
over-equalization.
If you set up the BT100 using an SCS-*, you must increase or decrease the JXP input pad by
the amount of change you made in the SCS-* value. Therefore, to maintain a proper gain
level, it is necessary to adjust the input pad value as follows:
ƒ For each increase in SCS-* value, decrease the input pad by 1 dB.
ƒ For each decrease in SCS-* value, increase the input pad by 1 dB.
ƒ If you replace an SFE with an SCS-*, reduce the value of the input pad by the value of
the SCS-*.
9 Measure the output level at the highest frequency.
It should be within 1 dB of the system design level. If it is not, you must adjust the midstage
pad (JXP) and/or the output pads (JXP OUT, JXP 1, JXP 3, JXP 4) accordingly. Refer to
Section 6, “Operating Tips,” for midstage/output padding information and recommendations.
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 3-5) to the LOW , MEDIUM , or HIGH position to specify
the amount of cable for which the TDU compensates at the highest frequency preceding the
BT100 station.
Low = 0 dB to 15 dB of cable, medium = 15 dB to 37 dB of cable, and high = 38 dB or more of
cable.
Figure 3-5
TDU cable selector
2 Position the drive control select jumper (Figure 2-13) temporarily in the MAN position and
perform the complete procedure described in Manual Gain Control if not already completed.