User Manual

MM102225V1, Rev. B
54
6.7 TX POWER CALIBRATION (MANDATORY)
Objective: The following procedure sets the output power level at the final rack RF
transmit port based on the transmit Antenna/Feedline Gains and Losses shown in the
following examples.
STEPS ACTION MISCELLANEOUS
1.
Calculate the required HPA TX Power
setting based on the required site ERP.
HPA TX Level may be calculated as
seen on the right.
Example of Calculating and Setting an ERP
of 50dBm:
Ant Gain in dB 10dB
Feed Line Loss in dB -3dB
Net Gain 7dB
Output Power 43dBm
Net Gain +7dB
ERP 50dBm
Setup
Procedure
Verify that ALL of the HPA
disable/enable switches are in the
Disable position.
2.
Select the RF Analyzer screen
• Set the correct channel frequency
• Set the TX Power to read dBm
• Set the Input Port to “RF Input”
• Set the Input Attenuation to
“Auto” (Default)
3.
Set the Sensitivity to “Normal”
(Default).
4.
Connect the Bird Power Monitor TX
Output Port to the HP 8920 RF In Port
using calibrated test cables and suitable
adapters as required.
5.
Connect the Laptop PC to the DCX
serving the HPA under test using the
black “Cisco” cable and the DB-9 to RJ-
45 Converter between the laptop “COM”
port and the DCX port.
6.
Turn on the Laptop PC and launch the
Hyper Terminal.
7.
With the PC connected to the DCX
serving the channel under test and
running a VT-100 Emulation.
8.
The purpose of this test is to adjust the
HPA transmit power level into the RF
transmission line to provide the site
specified ERP.