FAQs

What frequencies do CSI Bi-Directional Amplifiers (BDAs) work on?
CSI manufactures a wide range of amplifiers covering public safety and wireless service provider frequencies for Public Safety 700, Public Safety 800, SMR800, SMR900, GSM 900, DCS 1800, UMTS 2100, Cellular and PCS bands and sub-blocks.

How do I know which CSI Bi-Directional Amplifier to use?
To determine which amplifier to use, one needs to know the frequency band, Receiver Signal Strength Indicator (RSSI) of the serving cell site and the characteristics of the facility that requires coverage. Generally speaking the Model BDA140 & BDA150 are used in small office/home office (SOHO) applications and the Model BDA510 & BDA610 series are used in larger applications.

Contact CSI or your authorized CSI Authorized Reseller to determine the best BDA or Repeater for your application.

What is a link budget?
A link budget is the calculation of signal strength on a Distributed Antenna System (DAS) at coax connection points. Example of a downlink link budget for one indoor antenna DAS; Roof RSSI(-75dBm) + gain donor antenna (11dB) + loss coax to BDA (3dB) + gain BDA (62dB) + loss coax to indoor antenna (4.5dB) = -9.5dBm at indoor antenna port.

How much area will each antenna cover?
Antenna coverage is determined by the building characteristic path loss, frequency band(s), signal strength at antenna port and antenna type. For example, in a typical office application, an omni antenna with an output signal of +9.5dBm will maintain a coverage area of +85dB or better for 22k square feet on the cellular frequency band, 16k square feet on the PCS frequency band.

Does CSI manufacture In-Line Boosters?
Yes. CSI manufactures In-Line Booster (ILB) and Remote Booster Units (RBU). The ILB Model 130, is used to boost signal when using long coax runs between the BDA and indoor antennas or radiating cable. An ILB is installed at the far end of the cable before the indoor antenna or splitter. The ILB gain is the adjusted to compensate for the cable loss. The RBU is a multi-band in-line amplifier housing two or more in-line amplifiers. They are most commonly used in SMR800/SMR900 and Cellular/PCS combinations.

What is BDA oscillation?
Oscillation is when the outside antenna hears the amplified signal from the indoor antenna or the indoor antenna hears the amplified signal from the outside antenna. This event is similar to microphone/speaker feedback in audio. CSI amplifiers contain circuits to limit oscillation and oscillation shut down.