Motorola STARLINE SERIES Installation And Operation Manual page 38

Table 3-3
Gain reserve versus ambient temperature
Temperature
Above 110 F (43 C)
32 F (0 C) to 110 F (43 C)
Below 32 F (0 C)
8
Check the amplifier output tilt by measuring the high band- and low band-edge carriers.
High = channel 116 (745.25 MHz) or channel 136 (865.25 MHz)
Low = channel 2 (55.25 MHz) or channel 3 (61.25 MHz)
If the tilt is less than required, install a higher value input equalizer
If the tilt is greater than required, install a lower value input equalizer
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 use an SCS cable simulator and the design value is changed, you must also adjust the
input pad. For each 1 dB increase in SCS value, 1 dB of loss is introduced at 750 MHz or
1.1 dB of loss at 870 MHz. Therefore, to maintain a proper gain level, it is necessary to
adjust the input pad value as follows:
For each increase in SCS value, decrease the input pad by 1 dB for the MB75* or 1.1 dB
for the MB87*. Pads are available in 0.5 dB increments, therefore, use the closest value
possible.
For each decrease in SCS value, increase the input pad by 1 dB for the MB75* or 1.1 dB
for the MB87*.
If you replace an SFE with an SCS, reduce the value of the input pad by the value of the
SCS for the MB75* or a good estimate for the MB87*. Use the 1 dB loss at 750 MHz to
1.1 dB loss at 870 MHz ratio to be exact.
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 ( ) and/or the output pads (
JXP
" Operating Tips," for midstage/output padding information and recommendations.
Gain Reserve
4 dB
5 dB
6 dB
2 3/4) accordingly. Refer to Section 6,
JXP AND JXP
Amplifier Setup
MB*/* Installation and Operation Manual
3-13