RFI APM1317 User Manual page 132

APMxxxx Series User's Manual
REVERSE COUPLING
1. Keep the generator settings and test cable the same.
Move the generator cable to the "Antenna" port of the hybrid coupler and the 50Ω termination to the
2.
"Combiner" port of the coupler.
Click the "Refresh" button and note the power level shown in the "Reported Pwr - Rev" field.
3.
Adjust the "Reverse Coupling" value up or down until the displayed "Rev" power reading matches that in the
4.
"BTx Pwr" field. Click the "Apply" button each time a change is made to the "Reverse Coupling" value.
At this point, disregard the reading in the "Reported Pwr - Fwd" field.
5.
Once the "Reported Pwr - Rev" and "BTx Pwr" fields match, click the "Refresh" button a few times to confirm
6.
a stable reading and then click the "Apply" button and make no further changes to the "Reverse Coupling" field.
BTx POWER SETTING
In order to allow an accurate calculation of Combiner Insertion Loss, the value of transmit power applied to the combiner input
from each transmitter (in dBm) needs to be entered into the "BTx Power" field. There are two procedures which can be used:
•
Motorola Preferred
•
Optional
With the "Preferred" procedure, the actual base station input power to the combiner is measured and stored within the APM for
each station. With the "Optional" procedure, one station's input power to the combiner is measured and stored. The remaining
stations power levels are then simply entered into the APM GUI and saved. In either case, a final check is to verify the
combiner insertion loss for each channel. If the optional procedure has been used, any channel exhibiting incorrect combiner
loss (factory spec ± 1 dB), the TX power into that channel must be measured and saved into the APM using the preferred
procedure before beginning any combiner troubleshooting or retuning.
PREFERRED METHOD:
The APM may be used to measure and store the power for each channel. This is achieved by performing the following
procedure:
Connect a known good 50Ω load to the "Antenna" port of the APM hybrid coupler.
1.
Connect the cable from each station, one at a time, to the "Combiner" port of the APM coupler.
2.
3. Key the base station.
Click on the "Refresh" button at the top of the Calibration screen until a stable value is shown in the "BTx Pwr"
4.
field of the associated channel.
Click the "Capture BTx Pwr" button associated with the channel being measured.
5.
Click the "Apply" button after each capture.
6.
7. Repeat for each base station.
The APM will retain the measured power level until such time as it is changed either manually or by a repeating of the above
procedure at a later date.
Asia Pacific | EMEA | Americas 132