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Features

Spectrum

See RF activity on 2.4, 5 and 6 GHz as a live FFT trace, peak hold and waterfall from a WiPry Clarity, a Qualcomm WCN7850/QCNCM865 card or ESP32-C5 boards on a sensor.

Hardware dependent

Where: the mobile app's Spectrum tool, with the spectrum hardware attached to a connected sensor. The 2.1.36 Sensor console also has browser FFT, peak hold, waterfall and sequential 5/6 GHz WCN7850 band sweeps. ESP32-C5 spectrum is experimental.

Spectrum shows energy on the air that a packet capture cannot see, such as non-Wi-Fi interference, busy channels and wide transmitters.

What you need

  • iPhone, iPad or Android, connected to a sensor that has a shell (a Linux sensor, not an ESP32-C5 paired over Bluetooth).
  • One spectrum source on that sensor:
Source in the app Bands Levels
WiPry Clarity (USB on the sensor) 2.4, 5, 6 GHz dBm
Qualcomm WCN7850 / QCNCM865 (Android: Qualcomm) 5, 6 GHz Relative, uncalibrated
ESP32-C5 (Pi): one to six idle C5 boards on the sensor's USB 2.4, 5 GHz Relative, uncalibrated

Spectrum hardware and packet-capture radios are different capabilities. Confirm the exact model and transport before you buy or connect one. New USB adapters run beta code.

How to run a live spectrum view

  1. Connect the sensor in Devices.
  2. Open Spectrum. On iPhone, go to More › Spectrum; on iPad, it is in the sidebar. On Android, go to More › Spectrum. The screen shows Sensor connected. If it shows Select a sensor, go back and connect one.
  3. Pick the source:
    • On iPhone, use the Source segmented control: WiPry Clarity, Qualcomm WCN7850 / QCNCM865 or ESP32-C5 (Pi).
    • On Android, tap Source: … and choose WiPry, Qualcomm or ESP32-C5 (Pi). The Android menu lists this as "experimental ESP32 FFT".
  4. For WiPry only, tap Detect. You should see WiPry Clarity detected. The Qualcomm and ESP32 sources skip this step. Instead they show relative FFT levels (uncalibrated) (iPhone) or Relative FFT · uncalibrated (Android).
  5. Choose the band: 2.4 GHz, 5 GHz or 6 GHz. Only the bands that source supports are offered. The band is fixed while a session runs.
  6. Start:
    • On iPhone, tap Start Live. The button reads Live… while it streams.
    • On Android, tap Start Sweep, or Start FFT for the ESP32 source.

The status line counts sweeps or FFT frames as they arrive. 7. Tap Stop when you are done. The app stops the sensor's spectrum job.

You can't change the source or band while a session runs. Stop it first.

How to read the FFT and waterfall

  1. Switch between FFT and Waterfall with the view control.
  2. FFT plots level against frequency for the latest sweep. Channel markers mark the band. Drag across the chart to read the frequency under your finger. On Android, double-tap to clear the cursor.
  3. Turn on Peak hold (iPhone) or Max hold (Android) to keep the highest level seen at each frequency. On iPhone, it is drawn as a dashed line.
  4. For the relative sources, iPhone also offers Smooth live trace. This smooths the live line, not the stored data.
  5. Waterfall stacks successive sweeps over time; colour shows level. A steady vertical stripe is a constant transmitter. Short bursts show as broken streaks.
  6. On iPhone, tap Expand chart to give the plot the full screen. Tap Show controls to bring the controls back.

Tips

  • Relative is not dBm. Qualcomm and ESP32 levels are relative magnitudes. Compare them within one session and one source. Don't compare them with a WiPry's dBm or with another card's numbers. The chart's y-axis says Relative level or dBm. Check it before you read a value.
  • Qualcomm sweeps visit channels one at a time. The app sweeps the enabled channels in the band. Blank or grey ranges were not measured. On iPhone, each waterfall row is one completed channel cycle. One completed sweep is not a capture of the whole band at the same moment.
  • The Qualcomm radio must be idle. Stop any scan, capture or join on that card first. On a Mudi 7, connect over USB or Ethernet, not over the Wi-Fi radio you want to measure.
  • ESP32-C5 boards give gapped snapshots. Each board covers a slice of the band. The boards must be idle, not scanning or capturing.
  • Only one spectrum session runs at a time across your sensors.

If it doesn't work

What you see What to do
WiPry not found / WiPry Clarity not seen on USB (26ae:000c) Check the WiPry's USB connection and power on the sensor, then tap Detect again.
Start stays disabled Connect a sensor with a shell. For WiPry, a failed Detect blocks Start until the WiPry is found.
"Another operation is using the radio" Stop the scan, capture or join that is using the card, then start again.
"A spectrum sweep is already running on another device" Stop the other session first.
Waiting for first completed sweep… for a long time A Qualcomm sweep has to visit every channel before it draws. Wait for one cycle. If nothing arrives, stop, check that the radio is idle, and start again.

Browser spectrum controls · Unified image · Compatibility · Experimental work