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Confidential, Proprietary Information
Title: PCS FlexBeamer
®
RF Repeater
System A &O Manual
Doc. No.:
913002500
Rev.: 00
Page: 43 of
80NUMPAGES
2. DL Low Power Chain Gain Setting
2.1 Calculating the Gain of the DL FLEXBEAMER® units: The Max. gain of
the DL amplifiers in the RAC is 95 db. This gain amplification is composed of 4 successive
amplifiers- The BAU LNA, DL Rx ABT, the DL Tx ABT and the FLEXBEAMER® Beamer each
contributes approximately 15dB of the total FLEXBEAMER® adjustable DL gain.
The total gain of the DL Amplifiers of the RAC should be set to the value which will bring the Pilot
Ec received at the Donor Antenna to the required value at the FLEXBEAMER® input. Thus the
DL Gain of the Repeater System should be set to the following value:
Total Gain of DL in Repeater = +Pp–P’p [dB]……………..(2)
Where Pp denotes the DL signal input to the Donor Antenna ………….(3.1.1).
Example:
If the Pp measured at the Donor antenna is –60dbm, the total required gain of
the DL amplifiers of the RAC is +27-(-60)=+87db ………..(2.1)
2.2 Dividing the Gain between the FLEXBEAMER® Repeater stages: After
calculating the total DL gain of the FLEXBEAMER® Repeater per equation (2), the gain should
be divided between the 4 stages of the DL FLEXBEAMER® Repeater chain. following are the
recommendations for doing that:
a. Start the process by setting all the DCA attenuation in the BAU and RAC to
15.5dB.
b. Start reducing the Attenuation from max. at the BAU first(which is the first
amplifier in the chain.
c. The second DCA to reduce the attenuation is the Rx ABT(second amplifier in the
chain).
d. The third DCA to be reduced it’s attenuation will be the Tx ABT.
Example:
According to the process in example (2.1) , one needs to have +71db gain out
of the +95 db available. Following the steps a-c, the DL Tx ABT attenuator is
set to 14dB attenuation, and the Rx ABT set to –10dB.
Note
The DL Main and Diversity EIRP’s should be equal in order to achieve the
maximum diversity gain.
Check by reducing the DL Diversity TX gain by –15.5 dB and check the power
(actual or through the BSM indication) of the Main channel.
Repeat the same procedure for the Diversity channel by reducing the Main TX
channel.