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RFI BD Series BDA User's Manual
7.4
RF Level Configuration
The RF output of the BD Series BDA is adjusted on the BDASC module. This
is specified as a composite RF power rating. For example, in the standard
models, the BDASC can provide a maximum +22dBm for a single carrier, or
12dBm per carrier (total of 15dBm) for six (6) carriers. This duplexer and
cable losses should be added to this calculate the RF power out of the BDA.
In high power models, the High-Power Amplifier (HPA) is fitted in either or
both downlink and uplink RF paths. The HPA's have a fixed gain of 35dB
(+/- 2dB). A fixed 20 dB attenuator is fitted between the BDASC and the
HPA to firstly limit the input power into the HPA into a safe operating region
and secondly reduce the overall path gain in accordance to the
predetermined link budget.
It is very important to measure both UL and DL signal levels on site prior to
the installation of the BDA to ensure that BDASC and/or HPA(s) are not
overdriven.
WARNING: When HPAs are used, care should be taken to ensure they are not
overdriven by the available BDASC RF output levels. Maximum RF input into
HPA should never exceed +8dBm. Optional attenuators may be required to be
inserted between the BDASC RF output(s) and the HPA input(s) to maintain
HPA RF output levels at desired per- carrier output values, and at all times
below overload levels.
7.5
Gain Setting (BDASC)
The available configurable gain in each RF path of the BDASC is
between 39 and 70dB in 1dB increments, independently adjustable using
the wheel switches on the front face of the BDASC.
7.6
AGC Operation
The BDASC has Automatic Gain Control (AGC) capability that is enabled in
either (or both) downlink and uplink RF paths via the Command Line
Interface (CLI) and operates as follows;
The full available AGC range is 31dB, however this is dependent on the gain
(attenuator) setting. Full AGC is available when the gain in the selected path is
set to 70dB (no attenuation)
Figure 20- Gain Setting Switches on BDASC
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