INSTALLATION MANUAL for BI-DIRECTIONAL AMPLIFIERS Communication Components Inc. 299 Forest Ave, Paramus, N.J.
TABLE OF CONTENTS 1. Theory of Operation 2. Intended Application 3. Technical Description 4. Installation Procedure 5.
1. THEORY OF OPERATION The BDA-1819-60 is a bi-directional amplifier. It. is designed to exchange radio communications in buildings, basements, tunnels and other RF shielded environments. The BDA improves the sensitivity of base stations in indoor locations where there is a significant amount of cable loss in RF distribution systems. It contains two amplifiers providing amplification of RF signals in Up-link and Down-link frequency bands.
3. TECHNICAL DESCRIPTION The BDA-1819-60 bi-directional amplifier provides signal amplification in two separate frequency bands in both directions between two coaxial connector terminals. It is achieved by utilization of two frequency selective duplexers, which direct signals at two frequency bands present at the common port in two outputs. These duplexers provide sufficiently high isolation between two paths to prevent self-oscillation of the system. Detailed blockdiagram is shown in Figure 1.
Line B i -D irectional A m plifier B L O C K D IA G RA M B IAS TEE Rx/T x D U PLEXE R Rx BPF Tx BPF AMP AC Power Supply AMP V a r ia ble Atte nua tor V a r ia b le Atte nua tor Variable attenuators and AGC are optional AMP AMP Tx B PF Rx BPF R x/Tx D U PLEXE R BIA S T EE Figure 1 Bias Tee’s are optional
4. INSTALLATION PROCEDURE 4.1 NSPECTION CAUTION Use caution working with the bi-directional amplifier. Disconnect the 115 VAC from the amplifier prior to inspection. Open the enclosure of the bi-directional amplifier (BDA) and carefully inspect the inside assembly of the unit. Verify that all components are properly secured to the base of enclosure, there are no lose parts, and all interconnections are reliable. 4.2 SITE INSTALLATION 4.2.
Connect the “donor” side cable to the Up-link port of the BDA. Observe the level of the amplified signals on the spectrum analyzer. Adjust the gain (if the BDA option is so equipped) or external (internal, if so equipped) attenuator value to limit the power of the signals to +23 dBm for CDMA, +26 dBm for GSM, or +25 dBm for TDMA applications. 4.2.8 Repeat the same measurements connecting the spectrum analyzer to the Up-link port and cable to the Down-link port.
4.6.0 INFORMATION TO USER Any changes or modifications to this product as well as usage outside of specified electrical parameters, which are not expressly approved by manufacturer, could void the user’s authority to operate the equipment. 5.
Typical installation is shown in Fig.2 Two antennas are used in this set-up. One antenna with higher gain (10 dbi typically) and narrow beam, which is called Donor Antenna, is pointed to the Base Station. It provides down-link signals for the BDA input and directs up-link signals from the output of BDA to the Base Station. The second antenna, which is called Service Antenna, usually located on the ceiling of the service area.
