Disable USB-3 to improve the wifi range.

[RPIgoodSBC]

Is it possible to disable USB-3 by leaving USB-2 active with some parameter in /boot/config.txt?

I say this to avoid the loss of Wi-Fi performance with the rpi-4B adapter in the 2.4Ghz band due to interference caused by the USB-3.
It would be a good idea if developers found some ingenious way to get this easy for the user.

Yes, I know that you can use an extender and put an external Wi-Fi adapter but the Wi-Fi antenna of the RPI-4B is excellent and it is not good to lose Wi-Fi range in 2.4GHz by the use of USB-3 when we do not need to use it.

[dickon]

What makes you think USB 3 has any impact on wifi at all, OOI? It's news to me.

[RPIgoodSBC]

What makes you think USB 3 has any impact on wifi at all, OOI? It's news to me.

It has measurable impact on the band 2.4.

[dickon]

So I see. Are you experiencing any actual issues?

[RPIgoodSBC]

So I see. Are you experiencing any actual issues?

Not actually because I am using 5GHz band but I would like to know if it is possible to deactivate the USB-3 since in my house the 2.4GHz band goes much further and so I can use it preferably when I use the rpi headless.

USB 3.0* Radio Frequency Interference on 2.4 GHz Devices...

https://www.intel.es/content/www/es/es/ ... paper.html

It's an old problem like you see above paper pdf.

[dickon]

Yeah, I read it, about 20 minutes ago. AFAICS, if you're not actually using it, there won't be any interference generated, so, er, don't.

[RPIgoodSBC]

Yeah, I read it, about 20 minutes ago. AFAICS, if you're not actually using it, there won't be any interference generated, so, er, don't.

OK


I rephrase the question.

Is it possible to disable USB-3 by leaving USB-2 active in the four usb ports with some parameter in /boot/config.txt or in any other way?

[rin67630]

Is it possible to disable USB-3 by leaving USB-2 active in the four usb ports

If you plug only USB2 peripherals, you will get only USB2 signals on the wires (the USB3 specific lines are not connected) and hence no 2,4GHz HF interference.

[HawaiianPi]

If you have a USB 3.0 devices that you don't need max performance from, connect them to the USB 2.0 ports and connect your USB 2.0 devices to the USB 3.0 ports.

Or you could use a USB 2.0 extension cable to connect a USB 3.0 device as a USB 2.0 device (on the USB 3.0 ports).

Shielded cables or enclosures could help as well.

Seems like a pretty simple problem to solve with no need for a software solution.

Yes, 2.4GHz may have more range (sometimes), but it's usually slower than 5GHz, even with a weaker signal on 5GHz, and 2.4GHz is more susceptible to interference. So unless you are pushing the limits of your WiFi range, 5GHz is often the better option.

[RPIgoodSBC]

Is it possible to disable USB-3 by leaving USB-2 active in the four usb ports

If you plug only USB2 peripherals, you will get only USB2 signals on the wires (the USB3 specific lines are not connected) and hence no 2,4GHz HF interference.

Thanks.This is a way.
But, Is it posssible to made VIA chip to work only on USB-2 mode?
This way I don't need to remove my usb-3 memory (usb booting) from usb-3 port and put it on usb-2 port to avoid interferences and will have all 4 ports working on usb-2 mode.

It's only curiosity if it is possible that VIA usb chip works only on USB-2 mode via some parameter.

[RPIgoodSBC]

If you have a USB 3.0 devices that you don't need max performance from, connect them to the USB 2.0 ports and connect your USB 2.0 devices to the USB 3.0 ports.

Or you could use a USB 2.0 extension cable to connect a USB 3.0 device as a USB 2.0 device (on the USB 3.0 ports).

Shielded cables or enclosures could help as well.

Seems like a pretty simple problem to solve with no need for a software solution.

Yes, 2.4GHz may have more range (sometimes), but it's usually slower than 5GHz, even with a weaker signal on 5GHz, and 2.4GHz is more susceptible to interference. So unless you are pushing the limits of your WiFi range, 5GHz is often the better option.

It's only curiosity if it is possible that VIA usb chip works only on USB-2 mode via some parameter.

[rin67630]

This way I don't need to remove my usb-3 memory (usb booting) from usb-3 port and put it on usb-2 port to avoid interferences

If you boot from USB3 you won't be able to carry on with USB2. You ought to use premium shielded cables and an metal enclosure for your disk.

[RPIgoodSBC]

I have discovered a weird behaviour from usb-3 and wifi 2.4 on rpi-4.

If I boot a usb memory (raspbian host) that lsusb reports ID 0781:5580 SanDisk Corp. SDCZ80 Flash Drive (32Gb USB-3 memory) on the top USB-3 port then I can not connect to wifi 2.4GHz but I can connect without problems to wifi 5GHz.The rpi-4 and the router is at less than 1meter distance.
The rpi4 is in a very saturated hardware place in fact inside a case of my Big PC with the case opened.The router is above my Big PC case.

I am using a wireless keyboard on bluetooth mode and is working fine but I only connect to wifi 2.4GHz if I plug the usb3-memory (raspbian host) on the bottom port usb-3.I have tested this a lot of times and the results are consistent.
Ethernet is unplugged.
I can obtain about 10Mbits/sec download wifi on 2.4GHz band that is ok on this place that tested with others wifi adaptors.The maximum can achieve from my router on 2.4 band at 2 to 4 meters is near 40 Mbits/sec, any wifi adapter.
Wifi 5GHz is about 90 MBits/sec in the same place.

pi@4B:~ $ uname -a
Linux 4B 4.19.79-v7l+ #1273 SMP Fri Oct 11 18:23:45 BST 2019 armv7l GNU/Linux

Any ideas?

Seems that is better to use the bottom usb-3 port to avoid RF interference.

Definitely, yes the bottom usb-3 port is better to avoid RF on 2.4 band.I don't know the reason.
I have inserted another usb memory on the usb-3 top port and lose the 2.4 wifi.When unplugged I can conect to wifi 2.4.

[RPIgoodSBC]

I have tested now the rpi-3B+ versus the rpi-4B (usb booting raspbian on usb memory, noted in the other post) and tested on top and bottom usb-3 ports.

Rpi-3B+ at 10 meters from the router in another room and on 2.4GHz wifi band is about 6Mbits/sec..SD boot raspbian.

Rpi-4B at 10 meters from the router in another room and on 2.4GHz wifi band is about 2Mbits/sec usb-memory on bottom usb-3 port.

Rpi-4B at 10 meters from the router in another room and on 2.4GHz wifi band is about 0,28Mbits/sec usb-memory on top usb-3 port.

That's in the case I can connect 1 of each 4 times on top usb3-port.

Raspbian version is same for pi3 and pi4 and both are at the exact same distance from the router.

[jdb]

But, Is it posssible to made VIA chip to work only on USB-2 mode?

No.

I have discovered a weird behaviour from usb-3 and wifi 2.4 on rpi-4.

{...}
Seems that is better to use the bottom usb-3 port to avoid RF interference.

Definitely, yes the bottom usb-3 port is better to avoid RF on 2.4 band.I don't know the reason.
I have inserted another usb memory on the usb-3 top port and lose the 2.4 wifi.When unplugged I can conect to wifi 2.4.

Your pendrives are likely to be very poorly shielded or have incorrect grounding for the USB3.0 data pairs. Plugging into the top port means that RF currents flow over more exposed metal surface area (connector shell) than the bottom port and so can radiate better (aka worse for wifi reception).

Use a USB2.0 extension cable - the USB3.0 pendrive will fall back to connecting via USB2.0. Or, buy a less-leaky pendrive.

[RPIgoodSBC]

But, Is it posssible to made VIA chip to work only on USB-2 mode?

No.

I have discovered a weird behaviour from usb-3 and wifi 2.4 on rpi-4.

{...}
Seems that is better to use the bottom usb-3 port to avoid RF interference.

Definitely, yes the bottom usb-3 port is better to avoid RF on 2.4 band.I don't know the reason.
I have inserted another usb memory on the usb-3 top port and lose the 2.4 wifi.When unplugged I can conect to wifi 2.4.

Your pendrives are likely to be very poorly shielded or have incorrect grounding for the USB3.0 data pairs. Plugging into the top port means that RF currents flow over more exposed metal surface area (connector shell) than the bottom port and so can radiate better (aka worse for wifi reception).

Use a USB2.0 extension cable - the USB3.0 pendrive will fall back to connecting via USB2.0. Or, buy a less-leaky pendrive.

Thanks for response.
This make sense...

Plugging into the top port means that RF currents flow over more exposed metal surface area (connector shell) than the bottom port and so can radiate better (aka worse for wifi reception).

In the most cases I use 5Ghz band or ethernet but at more than 5 meters from the router is better to me the 2.4GHz band.
In any case I choose the bottom port usb-3 for the booting usb.

[peci1]

What about blacklisting the USB 3.0 driver?

Permanently:

Code: Select all

echo blacklist xhci_hcd | sudo tee /etc/modprobe.d/xhci_hcd.conf

Until reboot:

Code: Select all

sudo rmmod xhci_hcd