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APMxxxx Series User's Manual
OPTION 2 (Assumes all repeaters are set at the same power level. If not, use Option 1 procedure)
1.
Measure the output power, in dBm, of a repeater in the middle of the frequency range used by the system. Make the
measurement at the repeater TX connector using the Rohde & Schwarz (or equivalent) power sensor. The output of
the sensor should connect to the cable which connects the repeater under test to the combiner input.
On the APM GUI, enter this measured power into the "BTx Pwr" field for each of the repeater channels in the system
2.
associated with the TX Port being calibrated.
Click on the "Apply" button at the top right section of the screen.
3.
The following procedures apply to both Option 1 and Option 2:
FORWARD COUPLING:
Preset the "Forward Coupling" and "Reverse Coupling" values on the screen to "40.0" dB.
1.
Preset the "Antenna Feeder" to "0.0" dB
2.
Connect the Rohde & Schwarz (or equivalent) power meter to the "Cabinet TX Out" port (see drawing on Page 2) and
3.
terminate the output of the sensor into the site antenna network. Key a repeater, near the center of the frequency
range of the system, and note the forward power (in dBm).
Adjust the "Forward Coupling" value as needed until the "Reported Pwr – Fwd" matches the power measured in Step 3.
4.
NOTE: You must click on "Apply" after each change in the coupling value for the new value to take effect.
Click the "Refresh" button several times to ensure a stable power reading on the APM.
Set the "Reverse Coupling" value to the same as the "Forward Coupling" value and click "Apply"
5.
COUPLER TYPES (LEGACY or CURRENT)
Confirm that the coupler, for UHF and 700/800 MHz, is the latest model. The latest models will have the "FWD" and "REV" Type
N connectors at either end of the coupler, next to the DIN connectors. For reference, here are photos of both types of couplers:
"Legacy" Bi-Directional Coupler (VHF shown, legacy UHF/700/800/900 MHz models are similar in appearance but shorter)
"Current" Dual-Directional Coupler (used for UHF, 700/800/900 MHz only)
Note:
If your couplers are VHF, legacy UHF or legacy 700/800 MHz, perform the VSWR Calibration described on the
following pages, otherwise proceed to the Calibration Confirmation section
Asia Pacific | EMEA | Americas
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