Afar AR24027, Руководство оператора

Страница: 8 / 100

AR24027 Operator’s Manual
1-1
1 PRODUCT DESCRIPTION
1.1 Radio Overview
The AR24027 Wireless Ethernet Bridge is a license free radio that can be used to bridge Ethernet
LAN’s (Local Area Networks) across distances ranging from a few hundred feet to 50 miles (80 Km)
and beyond. It can be deployed in point-to-point or point-to-multipoint configurations. It can also be
paired with one of the Afar NetCrossing™ Gateway models to provide a full duplex synchronous
serial stream connection, in addition to the Ethernet interface, between two end points.
The AR24027 is a Spread Spectrum radio operating in the “Industrial Scientific and Medical” (ISM)
band from 2.400GHz to 2.4835 GHz. It is designed to provide a robust link under adverse conditions,
often encountered in this unlicensed band. This includes the following features:
1. All the electronics are housed in an environmentally sealed enclosure rated for outdoor
installation. You can mount the unit in close proximity to the antenna, which increases system
performance by avoiding RF cable losses or expensive rigid coax cables.
2. The radio RF bandwidth is much narrower than other unlicensed devices in the 2.4 GHz band.
This has several advantages, namely (i) the radio sensitivity is greatly improved allowing longer
ranges, (ii) there is a much larger number of non-overlapping channels to choose from, and (iii) it is
much easier to find an unused gap in a crowded spectrum.
3. For long range links in a crowded spectrum the most desirable receive frequencies at each end of
the link are often different. In the AR24027 the transmit and receive frequencies can be selected
independently of each other.
4. The radio incorporates spectrum analysis and timing analysis tools, which allow the operator to
quickly perform a survey of the RF environment without the need for spectrum analyzers.
5. Unique antenna alignment aid provides audio feedback proportional to the RSSI, freeing the
installer’s hands to adjust and tighten the antenna without having to hold or look at other
instrumentation.
The radio implements a transparent bridge algorithm, where each unit automatically learns the
addresses of all stations in the network and forwards over RF only the traffic that needs to be
delivered to the remote unit. This reduces the RF throughput required by the radio. If the radio is
used standalone, an indoor “power inserter” unit combines the power and Ethernet data into a single
CAT5 cable connected to the radio.
If the application requires a serial synchronous interface, the radios can be paired with the Afar
NetCrossing™ Gateway to provide both an Ethernet and a serial link of up to 1024 Kbps across the
same wireless connection. In this case the NetCrossing™ Gateway provides both the power and data
to the radio across the single CAT5 cable. Refer to the NetCrossing™ Gateway Operator’s Manual
for complete details.
The AR24027 is the building block for the Afar PULSAR wireless network. In a PULSAR network
all radios synchronize their trasnsmissions such that any co-located radios all transmit and receive at
the same time, thereby avoiding self-generated interference. This technique allows deploying large
networks with sites where upwards of 24 radios are co-located without self-interference.