OpenWrt Sub-Channels

For Developers
1

Hello friends

I have a ubiquiti device, this device automatically selects the channel and these channels do not appear on my other wifi devices.

When I connect to the ubiquiti device via ssh and run the "iwlist chan" command, it shows that it can use 360 channels.
iwlist chan (Ubiquiti)
ath0 360 channels in total; available frequencies :
Channel 33 : 5.165 GHz
Channel 34 : 5.17 GHz
Channel 35 : 5.175 GHz
Channel 36 : 5.18 GHz
Channel 37 : 5.185 GHz
...

I have removed its restrictions in the operating system.
iw reg get (my pc)
global
country HX: DFS-UNSET
(2402 - 2494 @ 40), (N/A, 27), (N/A)
(4910 - 6090 @ 40), (N/A, 27), (N/A)

But again, I don't see these channels. For example "Channel 33 : 5.165 GHz" how can I see this channel in my operating system and how can I connect?

iwlist chan (my pc)

wlan0 32 channels in total; available frequencies :
...
Channel 36 : 5.18 GHz
Channel 40 : 5.2 GHz
....

I have usb-wifi products with RT2770, RTL8814AU, MT7612U chipsets, but I can also buy usb-wifi products that can be attached to different external antennas.

2

To be clear, removing the restrictions (or setting your country code to evade local regulatory channel restrictions) is illegal.

Please clarify your activities and question in the event that I have misunderstood your goals.

1 Like
3

Right now, I just want to do a test. Why can't my own operating system use the same channels when Ubiquiti devices can use other channels in the same country? How can I solve this.

4

You'll have to ask the vendor of the OS, as well as the hardware vendor for the wifi chipset/adapter your computer uses.

What version of OpenWrt is this running?

ubus call system board
5

Ubiquiti runs these channels in the standard version. When I install openwrt on the Ubiquiti device, I can't see channels such as channels 33, 34, 35, the channel list starts from 36.

My test device:
{
"kernel": "5.15.134",
"hostname": "OpenWrt",
"system": "ARMv8 Processor rev 4",
"model": "Raspberry Pi 3 Model B Rev 1.2",
"board_name": "raspberrypi,3-model-b",
"rootfs_type": "ext4",
"release": {
"distribution": "OpenWrt",
"version": "23.05.0",
"revision": "r23497-6637af95aa",
"target": "bcm27xx/bcm2710",
"description": "OpenWrt 23.05.0 r23497-6637af95aa"
}
}

6

You'll need to ask UI about the channels they support and why it can go out of compliance for most places.

The Pi is a particularly bad wifi device -- extremely limited in its capabilities and not a good benchmark. It probably also remains in compliance.

All of that said, I am still not understanding what you are expecting here -- devices must be operated within the scope of the regulatory allowances in your country. Is there some reason that you are trying to run your devices out-of-complaince?

7

I don't want to run my devices out-of-complaince. I want to see the Ubiquiti Wi-Fi signal with my devices. I don't just do this using raspberry pi, I tried three different chipsets as usb wifi: RT2770, RTL8814AU, MT7612U Do Ubiquiti devices work illegally? Even so, isn't it possible for me to do this for testing?

8

I think you should ask those questions on the Ubiquiti site as well as the sites for your other devices since this is not specific to OpenWrt.

9

Ubiquiti devices can normally see these sub channels, but they don't see it when installing openwrt. Same device, same chipset.

10

The available channels depend on the hardware capabilities of your device's chipset, your location/country code, and the radio's configured channel width. Some vendor firmware may show a subchannels in their interfaces (via GUI or CLI) that are not directly selectable in the actual radio system... if they are selectable within the UI/CLI, it will typically 'snap' to the correct channel based on the channel width (this can also be represented as the start channel or the center channel, depending on the implementation of the firmware).

What UI does with their radios is a question for UI.

FWIW, the Pi3B that you listed earlier won't be able to use the 5GHz band anyway because its wifi is 2.4GHz only.

1 Like