User Manual

Mini-BDA OPERATION
Refer to figure 3 and 4 for adjustment access location and label.
Variable Step Attenuator
Mini-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 from the top of
the Mini-BDA enclosure (See Figure 4). Arrows on the shafts of these switches point
to the value of attenuation selected. The Mini-BDA gain can be determined by
subtracting the attenuation value from the gain reported on the Mini-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 Mini-BDA contains an
ALC feedback loop. The ALC circuit senses the output power and limits it to the
factory preset level (See Table 2). A red indicator lamp is located on the front panel
of the Mini-BDA and illuminates when the output power exceeds the ALC set point
(See below).
Downlink ALC Uplink ALC
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-8XX-0.5/0.5W-XX-AX at maximum gain with greater than -40
dBm average power incident on either BASE or MOBILE ports can cause
damage to the Mini-BDA.
Page 11