User's Manual
BDA OPERATION
Refer to Figure 3 & 4 for adjustment access location and label.
Variable Step Attenuator
BDA gain can be reduced by up to 30 dB in 2 dB steps using the variable step
attenuator. Gain adjustment is made with rotary switches accessible via the access
door on the BDA enclosure. Arrows on the shafts of these switches point to the value
of attenuation selected. BDA gain can be determined by subtracting the attenuation
value from the gain reported on the BDA Test Data Sheet for that side of the unit.
The attenuators are labeled for Uplink and Downlink.
ALC (Automatic Level Control)
To minimize intermodulation products, each amplifier in the BDA contains an ALC
feedback loop. The ALC circuit senses the output power and limits it to the factory
preset level of +25 dBm on the Uplink and +32 dBm on the Downlink.
ALC function is selected with on/off toggle switches located on each amplifier and
accessible via the access door on the BDA enclosure. A red indicator lamp located
on each amplifier illuminates when output power meets or exceeds the ALC set point.
The indicator is functional regardless of the position of the ALC switch.
Units are shipped with both ALC switches in the “ON” position. To ensure distortion-
free operation limited to the set point, keep the ALC’s turned ON.
To establish proper operating gain on the Uplink and Downlink sides, start with the
Uplink. Verify that the ALC switch is in the “ON” position. Observe the red indicator
lamp on the Uplink amplifier. Units are shipping with maximum attenuation. Decrease
attenuation one step at a time until the lamp is lit. Then, using the Uplink step
attenuator, increase the attenuation until the lamp goes off. Repeat the process for
the Downlink. The level indicator is accurate to +/- 0.4 dB of the ALC set point.
Operation of BDA-XXX-1/10W-X0-A at maximum gain with greater than -43 dBm
average power incident for -80 Models and -53 dBm average power incident for
-90 models on the MOBILE port or -38 dBm average power incident for -80
Models and -48 dBm average power incident for -90 models on the BASE port
can cause damage to the BDA.
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