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tools-survey

Wireless Survey

This menu lets you visualize your own (“internal”) & other peoples' (“external”) WiFi networks with your router as the reference point.

The menu has two parts. The graphics at the top display SSIDs as ellipses. There is also a table with detailed information on each WiFi network, both internal and external.

Since release 2024.2, the Canvas API has been used to help visualize the differences in frequency congestion between the 2.4 and 5GHz bands. See the example below.



The top of the ellipse represents the RSSI, and the bottom of the line through its middle represents the Noise level.

Signal strength (or “RSSI” - Received Signal Strength Indicator) is measured in negative values. Here, 0 is the strongest signal. In practice, a “usable“ WiFi network must be at least -84dBm.

-84dB (Worst signal) ←——> 0 dB (Best Signal)

You might still have working, but slow WiFi at -90dBm or less. It all depends on the client network adapter and external factors.

The channel selected affects the positioning of the ellipse. The width of the ellipse represents the actual channel width (20/40/80MHz). The numbers on the X-axis represent channel utilization (congestion).

Only graphics relevant to the device/configuration are shown. For example, on a dual-band router with only 5 GHz enabled, only the bottom canvas is visible. On a tri-band router with two 5 GHz channels, the data from both 5 GHz interfaces will be displayed on the same canvas.

The router's own SSIDs are shown in light grey, with a hard-coded RSSI of -10dbm when in A/P mode. The actual RSSI is displayed when the device is in Wireless Client mode/Media-Bridge mode or other special modes.

Note that some WiFi networks are configured not to broadcast the SSID. These are often referred to as “hidden” networks.




Hidden networks are shown with the 🕶️ symbol, so they are not left unnamed.

Noise and SNR

For each frequency, the noise level (interference) can be seen, expressed as a negative number. For RSSI, the closer to zero the number, the better. The opposite is true for Noise. For noise, the more negative the number, the better.

The top of the ellipse represents the RSSI, and the bottom of the line represents the Noise level.

SNR (Signal to Noise ratio) is also shown. This represents the amount of “good” signal. To calculate the SNR we add together the RSSI and the positive integer of the recorded dBm Noise. For example:


RSSI= -47 dBm
Noise= -89 dBm

SNR = RSSI* + (- Noise) = ( -47 + 89 ) = 42 dB


The red vertical bar is there to clarify what SNR represents. SNR is also displayed as a column in the table.

Restrictions

The sepia background represents frequencies where a central channel placement isn't possible or is restricted by government regulation. For example, channel 14 in the 2.4 GHz band is possible only in Japan and only using the 802.1lb protocol. Channels 12 and 13 in North America are other examples of these restrictions.

Canvas controls

The controls under the canvases allow you to customize the look of the SSID ellipses:




Display: Lets you filter which WiFi bands are shown.

The options are:

  • 2.4 GHz only
  • 5GHz only
  • Both (default).


This setting is intentionally not saved and will be forgotten at the next menu visit.

Style: represents how translucent the ellipses and noise figures will appear.
This is saved in a browser cookie.

SSID text (in pixels): tweaks the font size for SSID names on top of the relevant ellipse.
It also allows you to fully hide the SSID name on the charts. This is saved in browser a cookie.

Limit SSIDs: SSIDs are placed from the highest RSSI to the lowest Limit (0-40 default: 20) represents the maximum number of SSID visualized in every canvas shown. The Limit filters out from the weakest RSSI to the highest.

This setting doesn't affect the number of records in the table. However, only the RGB column will display/hide items based on the limit value. This is saved in a browser cookie.

Shuffle: randomizes the colours of the external (scanned BSSIDs) ellipses.

Detailed table



At the bottom of the page is a table showing the following information for each network:

  • Last Seen-the date and time that network was last detected
  • RGB - the unique colours associated with that SSID
  • SSID - that network's name
  • BSSID - the MAC address of that network's WiFi interface
  • RSSI - that network's Relative Signal Strength Indicator
  • SNR - the Signal-to-Noise ratio of that network
  • Signal Quality - ???
  • Control and Central channel, including band and sideband widths
  • Security - the security protocol active on the network
  • Rates (actually, the 802.11 protocol in use)

Wireless Survey Notes and Troubleshooting

At the bottom of the page is the standard refresh rate setting, and a new Timeout setting. This setting controls how long “last seen” SSIDs will be retained before they're pruned from the table/chart.

Information in this menu is designed to help you understand the nearby networks and help you to choose optimal channel/s for your own network.

While this tool is fully functional, you're advised to also use another WiFi scanner, such as a smartphone app. Doing so will give you both the router's perspective and the client's perspective.



tools-survey.txt · Last modified: 2024/06/17 17:06 by hogwild