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245U-E Wireless Ethernet Modem User Manual
Rev Version 2.24
Site Survey
Site Survey is a one-off snapshot showing the access points that are available for connection. This list is only
available on clients, and only available at startup of the module or by selecting “Background Scanning” on
the Radio page.
Figure 79
Connectivity / Site Survey
SSID
The service set identifier or network name used to identify a particular
network.
BSSID
The MAC (media access control) address of the access point.
CHAN
The radio channel being used.
RATE
Maximum radio data rate.
S:N
Signal strength and noise level. In the case above, the signal is -44 dB and the
background noise level is -88 dB.
INT
Beacon interval.
CAPS
Capabilities (Ref 802.11 Standard).
4.2 Channel Survey (Utilization)
Channel utilization gives a visual display of how busy the current channel is over a given time period.
Channel utilization is made up of three components—transmissions made by this radio, data received by
this radio, and noise or interference that this radio can hear. These three components may also be viewed
individually on the Custom Survey page. Channel utilization is logged by the radio for three separate time
intervals—every second for the last 60 seconds, every minute for the last 60 minutes, and every hour for
the last 60 hours.
The ELPRO 802.11 Ethernet modem utilizes a half-duplex radio channel for communications. At any
given time, an access point and its associated clients occupy a radio channel. These radio channels or
frequencies, are license-free and may contain interference from any number of other radio transmitters.
When installing or diagnosing a 245U-E modem, the potential capacity of a given radio channel will be
reduced by the existence of these other RF signals on the same channel.
Channel utilization allows us to see how much RF activity is on a given channel as a percentage of the total
utilization. A channel that is very busy will have high channel utilization (usually 50% or greater). Conversely
a channel that is quiet will have low channel utilization.
Channel Survey and Custom Survey can therefore be valuable tools to use when performing site surveys in
order to determine the best RF channel to use. It is also a valuable diagnostics tool for identifying the spare
capacity on a given channel, as well as possible sources of interference.
