CM5 Wi-Fi was slow on 2.4 GHz – now connecting to 5 GHz

uConsole
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Hello Everyone

Posting this in case it helps others using Raspberry Pi CM5 (in my case on uConsole).
Initially, Wi-Fi performance felt very slow, and it turned out the system was connecting to 2.4 GHz by default.

Problem

Out of the box, Wi-Fi showed:

freq: 2427

This means 2.4 GHz, which is:

  • Crowded

  • Limited in bandwidth

  • Often slow, especially in compact or metal enclosures

How I fixed it

First, I checked which band was being used:

iw dev wlan0 link

Then I forced the connection to use 5 GHz via NetworkManager:

nmcli connection show
nmcli connection modify "<connection-name>" 802-11-wireless.band a
nmcli connection up "<connection-name>"

I’m also using an external SMA antenna, installed via a Wi-Fi mod from Printables, which helped improve signal quality compared to the onboard antenna.

Result

After reconnecting, the link now shows:

freq: 5180

This confirms the CM5 is connecting to 5 GHz, and Wi-Fi performance is noticeably better and more stable.

Summary

  • CM5 may connect to 2.4 GHz by default, which feels slow

  • iw dev wlan0 link clearly shows which band is in use

  • Forcing 5 GHz and using an external SMA antenna significantly improves performance

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2

If you couldn’t bother writing your post here, and had a computer do it instead, why should anyone bother reading it?

Here’s what your post would have looked like had a human written it:

Oops, today I realized I was on 2.4GHz instead of 5GHz (which trades resiliency for bandwidth). I found out because I noticed it was slow and iw dev wlan0 link confirmed it. The trick to fixing it is nmcli connection modify "<connection-name>" 802-11-wireless.band a && nmcli connection up "<connection-name>".

Did you notice how that took 1 paragraph and a minute to read? If you don’t wanna take the time to even write that much, just post your prompt so we can go look at someone else’s program output ourselves.

3

and the most likely improvement has nothing to do with anything the thread is claiming to be about but the hidden note about switching to a different antenna instead of the pcb antenna stuck directly to the metal of the case

1 Like