Tip
It requires a radio capable of 20 Msps, such as a HackRF.
Last time I added Wi-Fi survey functionality that lets you know how much of each channel is used in a given place. This release adds Frames, a view that focuses on a single channel and looks at its content frame by frame.
My first attempt just printed all the frames in the order they arrived. So on a busy channel, which can carry a couple hundred frames per second, it was hard to see what was going on. Now it works more like an oscilloscope. It captures a "slice" of activity from the channel and holds it on the screen for a while. Then it captures another slice, and so on. In each individual slice you can see the frames in the order they arrived, along with their types, the speed at which they arrived, the time intervals between them, and so on. Select a frame or highlight a frame, the card on the right tells you exactly what data was read from that particular frame.
The river at the top is actually a zoomable overview of the selected slice. The keyboard shortcut for changing the view is z. In this view, you can see load (in frames per millisecond), rhythm (in 40 microsecond intervals), and anatomy (in 4 microsecond intervals).
Load (1 ms / cell)
Rhythm (40 µs / cell)
Anatomy (4 µs / cell)
You can also set what to wait for with t. Set the trigger to HT, for instance, and the slice starts on that frame.
The survey got significantly more stable in the last version. It turned out that each NET view was secretly calculating a spectrum that was not displayed on the screen, which used up an entire CPU core at 20 Msps.
Lock a channel first, on the survey or with m right on the Frames view.
Caution
The survey and frame is sensitive. Try to keep the LNA and VGA gain moderate, and the antenna away from your router, your laptop, or anything else talking on 2.4 GHz. Too much gain, or a transmitter right next to the antenna, will overwhelm the radio and flood the receiver with more than it can handle, making the numbers meaningless. The header will tell you when that happens (SAT, [FEED LOSS]: either reduce the gain a touch or move the antenna, and it'll settle).
Important
Announcement: Three radios are on their way to me and a huge thank you to SDRplay and Airspy for supporting the project. Don't expect a ton of new features at first. I'll be fixing what is currently there and enabling support for those radios correctly and tested on the real hardware as all the other radios in sdrtop are. Once that is all done, with three radios on the desk, sdrtop can head in a different direction towards things such as LoRa, DMR, GSM and more.
Full Changelog: v0.6.7...v0.6.8