seeed studio WifiMETRIX User manual

WifiMETRIX
HANDHELD CHANNEL ANALYZER
USER MANUAL
Last Updated: December 2017

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Contents
Introduction: WifiMETRIX Handheld Channel Analyzer......................................................................................... 2
Main Features ..................................................................................................................................................... 3
Menus ................................................................................................................................................................. 5
Short-cut Keys ..................................................................................................................................................... 6
Operational Modes.............................................................................................................................................. 7
Additional Features And Notes ........................................................................................................................... 12
Interpreting Results ............................................................................................................................................ 15
Calibration......................................................................................................................................................... 20
Firmware Updates ............................................................................................................................................. 22
Diagnostics ........................................................................................................................................................ 26
Acknowledgements ........................................................................................................................................... 27
FCC and CE Regulation....................................................................................................................................... 28
Licensing............................................................................................................................................................ 29

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Introduction: WifiMETRIX Handheld Channel Analyzer
WifiMETRIX is a new type of diagnostic tool that uses a dual-band 802.11 (i.e. Wi-Fi) chip to monitor
and troubleshoot Wi-Fi networks. It implements two important features —AirHORN and WifiPROBE.
The built-in Wi-Fi chip can perform both signal generation (AirHORN) and throughput diagnostics
(WifiPROBE) on each channel.
−The AirHORN function is an RF signal / channel generator that transmits stable and accurate RF
signals for each of the Wi-Fi channels, and aids in testing Wi-Fi antennas, RF shields and
wireless networks.
−The WifiPROBE function traverses each channel and measures the available transmit time.
When the goal is to choose the best channel —the one with the highest available throughput
—then WifiPROBE is the tool of choice.
WifiMETRIX operates in stand-alone mode and does not need to associate with an access point in
order to perform its functions. It is a truly unique device that is tailored for troubleshooting Wi-Fi
problems and computing the best channel.
WifiMETRIX has been designed to be intuitive and easy to use —no need to study large user manuals.
The best way to become familiar with the device and its capabilities is by experimenting —so, power it
on and give it a go.

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Main Features
The following are the main hardware features of WifiMETRIX (the following section describes more about
functional features).
Hardware features:
•Handheld device with dual-band 802.11 Wi-Fi chip
•Solid aluminum case plus silicon rubber boot protector
•Standard 50 ohm SMA antenna connector
•128×64 built-in LCD screen
•Includes dual-band antenna for 2.4x and 5.x GHz ISM bands
•Includes micro-USB cable for recharging
•Includes 50 ohm SMA terminator to protect antenna connection
•SMA terminator (dummy load) also used for calibrating the device
By far the most important feature on this list is the dual-band, 802.11 chip —no other tool uses an 802.11 chip
to perform Wi-Fi diagnostics. This is a huge advantage because it frees the user from having to interpret RF data
or metrics. Instead, WifiMETRIX’s 802.11 chip reports what it thinks about the health of each channel.
WifiMETRIX uses a metric based on IMMI —a patented technology based on the available transmission time of
each channel.

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The unit includes a 50 ohm impedance RF connector (standard female SMA format). This is used for attaching
the dual-band antenna that we include with the device. Feel free to substitute your own antenna —the only
constraints are you adhere to the 50 ohm requirement and your antenna includes a standard male SMA
connector.
When a compatible micro-USB cable is connected then the unit will begin charging (regardless of the position of
the power switch). With the micro-USB cable attached then the device’s power will come from that USB
connection. When the micro-USB cable is not attached, then the device draws power from its internal, lithium
battery.
When storing or transporting the unit we recommend attaching the 50 ohm SMA terminator (included) to
protect internal components from strong electric fields.

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Menus
WifiMETRIX uses the LCD screen and keyboard to access menus and features. It’s really pretty simple to use,
though we’ve summarized a few of the menus below. In general, you would use the UP / DOWN arrow keys to
highlight a menu option and then press the ENTER key to move to the next screen. You can always return to the
top-level main menu by pressing the MENU key.
When the device is powered-on it will display the main
menu. Use the UP / DOWN arrow keys to highlight an
option and then press the ENTER key to move to the next
screen. You can always return to this top-level menu by
pressing the MENU key.
This is the primary menu for AirHORN. Here you can
select which Wi-Fi band to use, output power and which
AirHORN mode to use.
This is the primary menu for WifiPROBE. Here you can
select which Wi-Fi band to use, and which WifiPROBE
mode to use

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Short-cut Keys
Below is a list of “short-cut” keys. However, due to the small keyboard, please be aware that certain key-presses
behave differently depending on the context menu. Feel free to experiment a bit and familiarize yourself with
the keyboard’s layout.
[MENU] Key
Return to the main menu —i.e. OPERATIONAL MODE
[ENTER] Key
Depending on the context, used to select highlighted menu option or
toggle between ACTIVE and PAUSED.
[RETURN] Key
Depending on the context, used to toggle between 2.4x and 5x GHz
bands or return to previous menu.
[UP] and [DOWN] Keys
Depending on the context, used to cycle through power output.
[LEFT] and [RIGHT] Keys
Depending on the context, used to cycle through channels.

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Operational Modes
WifiMETRIX features two “operational” modes — AirHORN and WifiPROBE. In AirHORN mode the device is used
as an RF channel / signal generator. Using 802.11 packet injection, AirHORN transmits stable and accurate RF
signals for each of the 802.11 (Wi-Fi) channels. In WifiPROBE mode the device provides unprecedented visibility
into the performance of a wireless network. The information collected and displayed helps to simplify
troubleshooting of interference-related problems and predicts the throughput performance of each 802.11
channel.
AirHORN Mode (Channel / Signal Generator)
When the device is powered-on it will display the main
menu. Use the UP / DOWN arrow keys to highlight the
‘AirHORN’ option and then press the ENTER key to move to
the next screen.

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This is the primary menu for AirHORN. Here you can select
which Wi-Fi band to use, output power and which AirHORN
mode to use. To change which Wi-Fi band to use, use the UP
/ DOWN arrow keys to select ‘WiFi Band’ and press the
ENTER key to toggle between the 2.4x GHz and 5x GHz ISM
bands. To change the output power, select ‘Power’ and press
the ENTER key to cycle through available power outputs —2
dBm through 18 dBm.
Also, in AirHORN mode there a 3 available ‘transmit’ modes
—‘Single’, ‘Traverse’ and ‘Pulse’ modes. Select one of the
transmit modes and press the ENTER key.
Single Mode
Here is an example of using ‘Single’ mode — where you can
select a channel in either the 2.4x or 5x GHz band and achieve
close to 100% duty cycle on that channel (at the normal 22
MHz-wide channel width). When using the 2.4x GHz radio
module you can choose from Wi-Fi channels 1 –13. When using
the 5x GHz radio module you can choose from Wi-Fi channels
36, 40, 44, 48, 52, 56, 60, 64, 149, 153, 157, 161, 165. There is
also a TX mode option —the radio can transmit either 802.11
packets or raw RF energy. When transmitting packets, 802.11g
is used by the 2.4x radio module and 802.11a is used by the 5x
radio module. After specifying the channel and TX mode select
NEXT and press ENTER.
The image below shows AirHORN in Single mode, using the
channel 6 in the 2.4x GHz band and the power output set at
11 dBm. Pressing the ENTER key toggles transmission
between PAUSED and ACTIVE. In the image below you can
see that AirHORN is transmitting on channel 6.

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Traverse Mode
Here is an example of using ‘Traverse’ mode — where you
can automatically scan through the set of 2.4x GHz or 5x GHz
channels. When using the 2.4x GHz radio module this mode
will automatically traverse channels 1 –13. When using the
5x GHz radio module this mode with automatically traverse
Wi-Fi channels 36, 40, 44, 48, 52, 56, 60, 64, 149, 153, 157,
161, 165. There is also a ‘Speed’ option — when ‘Slow’ is
selected then AirHORN will transmit for 30 seconds before
moving on to the next channel. When ‘Fast’ is selected then
AirHORN will transmit for 5 seconds before moving on to the
next channel. After specifying the ‘Speed’ NEXT and press
ENTER. As with Single mode, the next screen displays the
current band, channel and output power. Pressing the ENTER
key toggles transmission between PAUSED and ACTIVE.
Pulse Mode
Here is an example of using ‘Pulse’ mode — where you
“burst” on a specific channel, and then ‘off’ for a set interval.
Here the options are channel, burst duration (in seconds)
and ‘off’ interval (in seconds). As with the other AirHORN
modes, the next screen displays the current band, channel
and output power. Pressing the ENTER key toggles
transmission between PAUSED and ACTIVE.