Motorola RF Amplifier - Manual (Page 4)

4 STARLINE
RF Amplifier Quick Start Guide
5 Verify that the input level agrees with the design specification input. If the level is different
from design, adjust accordingly.
For example: the design level is 19 dBmV at the highest frequency and the design pad value
is JXP-3B. If the actual measured level is 21 dBmV, then you must change the pad to a
JXP-5B.
If the actual levels are significantly different from the design levels, it is recommended that
you investigate or consult system management before proceeding.
6 Connect the signal level meter to the output test point and tune the meter to the high-end
channel.
7 Turn the manual gain reserve ( MAN ) control to maximum (fully clockwise) and then reduce
the output by the amount indicated below:
Amplifier Above 110ºF 32ºF to 110ºF Below 32ºF
BLE*/* 3 dB 4 dB 5 dB
MB*/* 4 dB 5 dB 6 dB
BT*/* 4 dB 5 dB 6 dB
MBE*/* 3 dB 4 dB 5 dB
8 Check the amplifier output tilt by measuring the high band- and the 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 SFE- *-*
! If the tilt is greater than required, install a lower value SFE- *-*
! 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
preferential to over-equalization.
9 You must adjust the input pad if you use a STARLINE Cable Simulator (SCS- *) and the
design value is changed.
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 each decrease in SCS- * value, increase the input pad by 1 dB.
! If you replace an SFE- *-* with an SCS-*, reduce the value of the input pad by the
value of the SCS- *.
10 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 interstage pad and/or the output pads
accordingly.
The input pad is normally changed to accommodate excessive input levels. Because it only
attenuates excess signal, it has no effect on the overall performance of the amplifier.