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Spectrum analysis involves the use of special RF equipment designed
to listen to and analyze the frequency bands utilized by Wi-Fi
devices. Because these bands are unlicensed, they are often shared
with non-Wi-Fi sources of RF signals, such as wireless video
cameras, microwave ovens, or cordless phones, which cause
interference. The purpose of spectrum analysis is to detect and
identify such sources of interference, eliminate them, and/or
identify the WLAN channels with minimal interference.
Hardware Requirements
CommView for WiFi can perform spectrum analysis by interfacing
with
Wi-Spy,
a USB-based spectrum analyzer. Wi-Spy can be purchased from
TamoSoft or directly from MetaGeek.
CommView for WiFi supports the following Wi-Spy models:
·Wi-Spy
DBx (dual-band, 2.4 GHz and 5 GHz)
·Wi-Spy
2.4x (single-band, 2.4 GHz)
·Wi-Spy
2.4i (single-band, 2.4 GHz)
Note that CommView for WiFi DOES NOT support the oldest Wi-Spy
model (“Wi-Spy original” with a green logo) or 900x models.
When a dual-band model, Wi-Spy DBx, is used, it continuously sweeps
both bands, one after the other. Using two Wi-Spy DBx units
simultaneously might improve data quality, as CommView for WiFi
would dedicate each of the units to one band only.
Spectrum Data Graphs
When Wi-Spy is plugged in, a live spectrum picture is displayed on
the Channels
and Spectrum pane
of the main CommView for WiFi window, as shown below.
The spectrum pane is similar to the one you can see
in Chanalyzer,
a spectrum analysis application by MetaGeek that comes with Wi-Spy.
By default, the Channels
and Spectrum pane
displays one or two planar spectrum graphs for single- and
dual-band Wi-Spy models, respectively.
The appearance of the graphs can be controlled via the context
menu. Select 2.4
GHz, 5.0
GHz,
or Dual to
have the spectrum pane display one of the single frequency bands or
two bands simultaneously (5.0
GHz and Dual are
available only if you have a dual-band Wi-Spy model.)
Select Current
Level to
display a line that shows the current signal amplitude;
select Max
Level to
display a line that shows the maximum signal amplitude.
The X-axis item
allows you to select the measurement units of the horizontal axis;
you can choose between Frequency in
MHz and Channel numbers.
By enabling the Waterfall view,
you can have the application graph amplitude over time.
Select 1/3, 1/2,
or 2/3
of the window size to
adjust the area of the window occupied by the waterfall graph. The
spectrum pane can be detached from the main application window and
displayed as a separate floating window. Use
the Detach
Window and Attach
Window to
perform the respective operations. You can also hide
the Channels
and Spectrum pane
by checking or unchecking the View
=> Channels and Spectrum item
in the main application menu.
Note that in order to view spectrum data in CommView for WiFi, you
must close Chanalyzer if it is running; Wi-Spy cannot be accessed
and controlled by multiple applications simultaneously.
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