Compare sensor boards

A capture passes through five stages: the radio hears the frames, the host bus carries them to the processor, memory holds them, storage saves them, and a link sends them to your phone or analyser. A job runs out at its narrowest stage, and that stage differs from job to job.

Each board, stage by stage

Read across a row to see a board from radio to link. Scroll the table sideways on a phone.

How sure each number is: measuredspecqualifiedexpectedunknown
Measured on our hardware; from the maker’s spec; what WLAN Commander has qualified so far; expected from the same part measured elsewhere; or not known yet.

From the radio to your file

Six common jobs, each followed from the air to the saved file. The red stage is where the job runs out. The tags show what software does about it, and at which stage.

Which board for which job

A Limited rating names the stage that limits it. Not yet supported means the hardware can do it and WLAN Commander does not offer it yet. We have not yet measured complete captures end to end on every board; a field test is planned for when capture buffering ships.

What you can buy

The same board comes in versions, and some change the numbers above. SD card speed depends on the card you buy, not the board.

What software does about it

• Headers Only (128 bytes). Keeps each frame’s 802.11 header and information elements, a small fraction of the data. It trims after the host bus, so it cannot help a saturated bus.
• Save on Remote. The sensor writes the file itself, so the link to the phone is out of the path while capturing. Storage write speed sets the limit instead.
• A narrower channel plan. Fewer channels and longer dwell mean less to carry and more of what you care about.
• Buffer bursts in memory (in development). Hold a burst in RAM and send it on at the link’s pace. More memory rides out longer bursts.

How long a buffer could last, by arithmetic only: a 450 Mb/s burst, the rate measured in the NanoPi storage test, arriving faster than it drains. Free memory figures are assumptions; buffering has not shipped.

Reference

Link ceilings

Your phone is a stage too. Only iPhone 15 Pro and later Pro models have USB 3 on their USB-C port. Other USB-C iPhones, every Lightning iPhone and many Android phones run at USB 2.0, so a stream to them is capped near 300 Mb/s, whatever the sensor supports.

Wi-Fi rates by width and MCS

The most a 2×2 Wi-Fi 7 radio can be sent at each width (standard 802.11be PHY rates, 0.8 µs guard interval; not measurements). Real traffic on a busy channel is roughly half to three-quarters of these.

Intel cards on a PCIe 2.0 link

Intel’s Linux driver checks how fast the BE200’s PCIe link trained. Below 8 GT/s (PCIe 3.0), which is every board here except a Pi 5 set to Gen3:

• As a client, the BE200 stops advertising MCS 10 to 13 at 320 MHz, so it tops out at MCS 9: a 3.84 Gb/s PHY rate at 2×2. Narrower widths are unchanged.
• In monitor mode it still captures at 320 MHz. A BE200 on a NanoPi’s PCIe 2.1 link recorded 802.11 frames on a 320 MHz channel in 6 GHz, and one on a WLAN Pi Go’s Gen2 link tuned 320 MHz. We have not yet checked that frames sent at MCS 12 and 13 decode on that link.
• Older kernels were stricter. Linux 6.5 to 6.14 removed 320 MHz entirely on a slow link, which is why earlier tests said a BE200 could not do 320. The boards we tested run newer kernels.
• The app offers up to 160 MHz on Intel cards today. Lifting that limit is planned for a later release.

Qualcomm’s driver (ath12k, for the QCNCM865) has no such check, and the card tunes 320 MHz. MediaTek’s MT7925 never offers 320 MHz in its driver; only the newer MT7927 does.

Capture modes and what they cost

The names are the labels in the app’s capture settings.

Storage and SD cards

A busy 2.4 GHz capture wrote about 0.8 MB/s. About 450 Mbit/s of frames is 56 MB/s of writes, several times what the microSD cards we measured sustain (12 to 22 MB/s). When writes fall behind, frames drop. The measurements are in the storage field note and the NanoPi build guide.

On boards with an SD card, the card usually sets the write speed. The markings below are minimums from the SD Association; a card can beat its rating. The two cards we measured on the NanoPi wrote 12.1 and 21.7 MB/s, so benchmark a card before trusting it with full captures. Board slots: the NanoPi’s reads top out at 67 to 70 MB/s (measured); the Pi 5 runs SDR104 (104 MB/s bus); the Pi 4 and the CM4 run DDR50 (50 MB/s bus).