B+B SmartWorx APPN551 Manual De Usuario
APPN-TT551 Databook
B&B Electronics, Inc.
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flying lead antennas tend to provide more performance and flexibility than other
approaches, since the location of the antenna is not determined by the host PCB
design. The assembly of a system using embedded flying lead antennas may be
slightly more complex, as the antenna is not necessarily mounted on the host
PCBA.
approaches, since the location of the antenna is not determined by the host PCB
design. The assembly of a system using embedded flying lead antennas may be
slightly more complex, as the antenna is not necessarily mounted on the host
PCBA.
7.5
Antenna Location
The importance of location cannot be over stressed. It can often be the
difference between the success and failure of a Wi-Fi implementation.
difference between the success and failure of a Wi-Fi implementation.
There are several factors that need to be considered when determining location:
Distance of Antenna from radio.
Location of host system.
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Proximity to RF blocking or absorbing materials.
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Proximity to potential noise or interference.
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Position relative to infrastructure (Access Points or Laptops).
Orientation of host system relative to infrastructure.
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Is it known?
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Is it static?
The following things need to be considered during the development process:
1. Minimize the distance between the radio and the location of the antenna. The
coaxial cable between the two impacts the Transmit Power and Receive
Sensitivity negatively. B&B recommends using 1.32-1.37mm outer diameter
U.FL coaxial cables.
Sensitivity negatively. B&B recommends using 1.32-1.37mm outer diameter
U.FL coaxial cables.
2. Minimize the locations where metal surfaces come into contact or are close
to the location of the antenna.
3. Avoid locations where RF noise may occur, whether it is close to or
overlapping the ISM bands. This would include microwave ovens and
wireless telephone systems in the 2.4GHz frequency range.
wireless telephone systems in the 2.4GHz frequency range.
4. Mount the antenna as high on the equipment as possible.
5. Locate the antenna where there is a minimum of obstruction between the
antenna and the location of the Access Points. Access Points are typically
located in the ceiling or high on walls.
located in the ceiling or high on walls.
6. Keep the main antenna’s polarization vertical, or in-line with the antenna of
the Access Points. 802.11 systems use vertical polarization and aligning both
transmit and receive antenna maximizes the link quality.
transmit and receive antenna maximizes the link quality.
All of these factors will influence connection quality.
7.6
Performance
Performance is difficult to define. The appropriate metric changes with each
application, and may be a combination of parameters and application
requirements. The most important characteristic will normally be link quality. This
can be defined as the available bandwidth between the two devices. The lower
the link quality, the less likely it will be that the devices can communicate.
application, and may be a combination of parameters and application
requirements. The most important characteristic will normally be link quality. This
can be defined as the available bandwidth between the two devices. The lower
the link quality, the less likely it will be that the devices can communicate.
Measurement of link quality can be made in several ways; Bit Error Rate (BER),
Signal to Noise (SNR) ratio, Signal Strength and distortion. The link quality is
used by the radio to determine the link rate. In general, when the link quality for
Signal to Noise (SNR) ratio, Signal Strength and distortion. The link quality is
used by the radio to determine the link rate. In general, when the link quality for