FIELD NOTE · WI-FI SCANNER
Stop guessing
which channel is busy.
macOS removed the airport command-line tool. Wi-Fi Scanner is the native replacement: every nearby network, with signal strength and channel, on a single pane. See the channel everyone is fighting over and the empty one your router could move to.
Sort by RSSI or by channel; click any row for details.
What you see
One row per nearby network (BSSID). Each row shows the SSID, RSSI in dBm (closer to zero is stronger; -55 dBm is great, -80 dBm is iffy), the band (2.4 / 5 / 6 GHz), and the channel number. Sort by signal to find the strongest networks first; sort by channel to spot which channels are crowded.
Why the channel matters
Wi-Fi is a shared medium. If your router is on channel 6 and three neighbours are also on channel 6, every packet on that channel waits its turn. Latency rises, throughput halves, your video call stutters. The fix is moving your router to a channel with fewer signals on it. Wi-Fi Scanner is the map you need to make that decision.
2.4 vs 5 vs 6 GHz, in one paragraph
2.4 GHz has 11 channels in most regions, but only three (1, 6, 11) do not overlap. Any other choice causes interference with neighbours. 5 GHz has dozens of non-overlapping channels and far fewer neighbours, which is why it usually performs better. 6 GHz (Wi-Fi 6E and Wi-Fi 7) is even quieter because almost nothing is on it yet. If your router and your Mac both support 6 GHz and you can move there, you will probably forget what slow Wi-Fi feels like.
How to pick a channel
Open Wi-Fi Scanner, sort by channel, look at the band you want to live on:
- 2.4 GHz. Pick whichever of channels 1, 6, or 11 has the fewest networks within 5 dB of yours. Ignore weak (-85 dBm and below) networks; they are too far away to interfere.
- 5 GHz. Pick any channel with no networks within 10 dB of yours, in the lower band (36-48) or upper band (149-165) depending on what your router supports. Some channels (DFS) trigger radar checks that pause Wi-Fi briefly; if you see drops on a DFS channel, switch off it.
- 6 GHz. Almost any channel works; pick whichever is empty. If two are empty, pick the one with the wider bandwidth your router supports.
Then change the channel in your router admin. Your Mac reconnects automatically.
Pairs with Latency History
If Latency History shows jitter that comes and goes through the day, especially in the early evening when neighbours come home, channel congestion is the most common explanation. Open Wi-Fi Scanner during one of those bad windows; if your channel has gained company, that is the cause.
Where to find it in the app
Click the menu-bar icon, scroll to the bottom of the popover, click Insights. Wi-Fi Scanner sits at the bottom-right of the workspace. The list refreshes on demand; click the column header to re-sort.
TL;DR
Wi-Fi is a shared medium and the channel is the queue. Wi-Fi Scanner shows you the queue length on every channel. Pair with Latency History to confirm congestion is what is hurting you, then move your router to a quieter channel.