 Product & Services FAQ
Can I contact CSI to design and install an in-building system?
Yes. CSI offers complete turnkey services for in-building wireless systems.
A CSI technician performs a pre-installation site survey to evaluate the system
requirements. In-house engineers design the Distributed Antenna System (DAS),
indoor antenna locations, cable routes, equipment placement and wireless coverage
with state of the art design software. After a pre-installation review meeting,
installation is performed in a professional and expeditious manor by trained
personal. No installation is complete until our customer is completely satisfied.
What frequencies do CSI Bi-Directional Amplifiers (BDAs) work on?
CSI manufactures a wide range of amplifiers covering public safety and service
provider frequencies for SMR800, SMR900, 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.
How is an in-building Distributed Antenna System installed?
A small low-profile directional antenna is mounted on the roof of the building
and aligned towards the donor serving cell site. This antenna receives the downlink
signal from the cell site and transmits the uplink signal from the wireless
handset within the building back to cell site. A BDA is mounted in a utility
or telecommunications room and small interior antennas are installed in the
ceiling. The indoor antennas locations are strategic to best distribute the
signal within the building. Coax cable is routed between the outdoor antenna
and BDA outside antenna port through a lightning arrester and grounding kit.
Coax cable is installed above the ceiling connecting the indoor antennas using
splitters and directional couplers to the BDA inside antenna port.
What if I have a very large facility or campus that requires wireless coverage?
CSI has designed and installed well over 2500 in-building systems including
many Fortune 500 companies, universities, airports and tunnels. Fiber Optic
equipment may be used to transport signals over existing backbones between wings
and buildings. Please contact CSI to discuss your requirements.
What is a link budget?
A link budget is the calculation of signal strength on a Distributed Antenna
System (DAS) at coax connection points in dBm units. Example of a downlink link
budget for one indoor antenna DAS; Roof RSSI(-75dBm) + gain donor antenna (11dBm)
+ loss coax to BDA (3dBm) + gain BDA (62dBm) + loss coax to indoor
antenna (4.5dBm) = -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 +85dBm or better for 22k square feet
on the cellular frequency band, 16k square feet on the PCS frequency band.
How much loss do splitters have?
The loss of a splitter is 10LOG of the number of ports plus the insertion loss
of the device.
| Device |
Ports |
Insertion Loss |
Total Loss |
| CSI-S2BSC |
2 |
0.5 |
3.5 |
| CSI-S3BSC |
3 |
0.5 |
5.27 |
| CSI-S4BSC |
4 |
0.5 |
6.5 |
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 then the ILB gain is
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 prevent oscillation or oscillation shut down.
If I want to add Web Monitoring capability to an existing system, what will
be required?
A Web Monitor, two additional RF cables and couplers, and a compatible BDA
are the minimum requirements. However, sometimes the RF environment may require
additional filters or a separate access antenna for the Monitor. Each installation
is unique and needs to be assessed individually.
Do I need one Web Monitor for each BDA in my system?
No, but that depends on the size of the installation. Each Web Monitor can
access and control up to 7 BDAs. A single bus of four wires connects each BDA
with the next devices, which can be either a BDA or the Web Monitor. The total
length of the bus that connects all devices must not exceed 500 meters.
For more information on CSI products, services or installation questions, please
contact us at 1.877.844.4274 or email sales@cellularspecialties.com.
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