Motorola BT100 operation manual Thermal Drive Unit

3-10 Amplifier Setup

ƒLow = channel 2 (55.25 MHz) or channel 3 (61.25 MHz)

ƒIf the tilt is less than required, install a higher value input equalizer

ƒIf the tilt is greater than required, install a lower value input equalizer

ƒIf 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:

ƒFor each increase in SCS-* value, decrease the input pad by 1 dB.

ƒFor each decrease in SCS-* value, increase the input pad by 1 dB.

ƒIf you replace an SFE with an SCS-*, reduce the value of the input pad by the value of the SCS-*.

9Measure 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:

1Place 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

2Position 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.

BT100 Installation and Operation Manual