hakenhand
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Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Wed Jul 31, 2019 11:43 am

DE Wifi Country.jpeg
DE Wifi Country.jpeg (105.92 KiB) Viewed 6336 times
US Wifi Country.jpeg
US Wifi Country.jpeg (117.19 KiB) Viewed 6336 times

Hello, everybody.
I come from Germany.
I have problems with the WIFI of the Raspberry 4b.
The RPi 4b does not connect to the same channel width (80mhz) as the RPi 3b+.
The RPi 4b only connects according to the wifi n standard, not according to the ac standard, therefore with lower bandwidth.

I have attached two screenshots to make it clear.

If I set the Wifi Land to US the connection to the Fritzbox is at ac standard and 80mhz channel width but the connection is constantly broken and the signal strength is very low.

I use software with the latest updates on both Raspberry Pi. Both devices are about 3 meters away from the router.

How can I change this behavior of the RPi 4b?
Greetings


PS. translated with Deepl.com

hakenhand
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Joined: Wed Jul 31, 2019 9:37 am

Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Wed Aug 07, 2019 8:00 am

Hello
does anyone have a similar problem or even a solution?

Thank you

hakenhand
Posts: 6
Joined: Wed Jul 31, 2019 9:37 am

Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Thu Nov 07, 2019 11:59 pm

just wanted to say that despite all the updates in Raspbian till today, nothing has changed yet.
Still slow Wifi,
still the same situation as in my first post.

Any help is welcome.
Thank you

trejan
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Fri Nov 08, 2019 12:27 am

The 3B+ and 4B use the same Cypress CYW43455 chip for WiFi/Bluetooth. Have you updated to the latest version of Raspbian on both Pi boards?

Diablo2_Fan
Posts: 21
Joined: Thu Aug 01, 2019 6:47 pm

Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Fri Nov 08, 2019 4:13 pm

I have similar problems after the EEPROM update to 000137ab.
A 2.4 GHz connection to the AP isn't possible anymore and the 5 GHz connection is really weak :-(

Michael Kofler from pi-buch reported wifi problems, too:
https://pi-buch.info/eeprom-updates-fue ... erry-pi-4/

hakenhand
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Sat Nov 09, 2019 11:16 am

now that i actually equipped the 3b+ with the last raspbian buster, the 3b+ shows the same error as the Pi4

what could be the reason?
thank you
Image

renice123
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Sat Nov 09, 2019 11:31 am

Based on your messages, the conclusion is obvious - the cause of errors is to use the Baster OS. I also already found some errors critical for me. Mounting cloud storage is still not working well. Buster is an unstable system. We will suffer =)

Diablo2_Fan
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Mon Nov 11, 2019 9:38 am

Changing the HDMI resolution solved my WIfi problem.
Also plugging the cable to the micro-HDMI-1 port improved the signal quality.

I think it's a HDMI bug, because I'm using the official HDMI-cable.

jamesh
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Mon Nov 11, 2019 10:06 am

Diablo2_Fan wrote:
Mon Nov 11, 2019 9:38 am
Changing the HDMI resolution sloved my WIfi problem.
Also plugging the cable to the micro-HDMI-1 port improved the signal quality.

I think it's a HDMI bug, because I'm using the official HDMI-cable.
Thanks for the datapoint -that's quite interesting.

I wonder if you could try some tests? Are you able to SSH in, if so can you turn off the HDMI when running in the problematic mode, then see if the Wifi improves?

Use `vcgencmd display_power 0` to turn off power to the current display. (https://www.raspberrypi.org/documentati ... cgencmd.md)

You can check wifi SNR using, IIRC, `iwlist accesspoints`, so that would also be useful information to have when running various different HDMI resolutions.
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Mon Nov 11, 2019 11:50 am

"iwlist accesspoints" doesn't work for me. You can get most information from "iwconfig wlan0", just not the channel width. "iw wlan0 info" gets you a different subset including channel width but not the SNR. "iw reg get" will show what is supported for each group of channels, but that might not include a handshake with the WiFi firmware to verify that it is possible and permitted.

What's that GUI you are using? It doesn't look like a standard Raspbian component, and it would help to stick to standard, command line utilities when debugging this.

hakenhand
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Mon Nov 11, 2019 12:52 pm

if the question which gui I use is addressed to me, it is the default Raspbian Buster desktop.
The screenshots above are from the web interface of my Wifi-router.

PhilE
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Mon Nov 11, 2019 1:07 pm

I too am only getting 40MHz channels except when selecting the US regulatory domain, but for me there's no difference in behaviour between 3B+ and 4B.

Starting with HDMI connected, run this set of commands. Leave it running for 5-10 seconds, then unplug the HDMI cable and hit Return on the keyboard to mark the changeover point, leave that for 5-10 seconds then reconnect the cable, hitting Return again. I don't see any significant difference between the connected and disconnected case, but if anything the link is worse without HDMI connected - where I set and how I lean over the Pi has a much larger effect, so watch your posture.

Where possible it helps to see measurements from the Pi's perspective, although seeing SNR/Link Quality from both sides is interesting. If you see that the Pi's Link Quality varies less than the Router's then it might be that the monitor is interfering with Router.

Kendek
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Mon Nov 11, 2019 1:29 pm

PhilE wrote:
Mon Nov 11, 2019 1:07 pm
I too am only getting 40MHz channels except when selecting the US regulatory domain, but for me there's no difference in behaviour between 3B+ and 4B.
Qualcomm error message when trying to connect to AC-only mode:

Code: Select all

deny assoc request, no vht caps in pure 802.11ac mode
If doing pure 802.11ac mode, don't accept STAs without VHT capabilities.

It is good if country=US.

Diablo2_Fan
Posts: 21
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Mon Nov 11, 2019 8:07 pm

jamesh wrote:
Mon Nov 11, 2019 10:06 am
I wonder if you could try some tests? Are you able to SSH in, if so can you turn off the HDMI when running in the problematic mode, then see if the Wifi improves?

Use `vcgencmd display_power 0` to turn off power to the current display. (https://www.raspberrypi.org/documentati ... cgencmd.md)

You can check wifi SNR using, IIRC, `iwlist accesspoints`, so that would also be useful information to have when running various different HDMI resolutions.
I haven't SSH but I wrote this quick & dirty script:

Code: Select all

#!/bin/bash

echo "values with enabled hdmi:"
echo
iwconfig wlan0
sleep 1
echo
echo
echo "values with disabled hdmi:"
echo
vcgencmd display_power 0
sleep 30
iwconfig wlan0
sleep 1
vcgencmd display_power 1
read -n 1 -s
Here are two examples:

1920x1080:
I think it's interesting because it's not able to connect to the AP while the screen is on.
values with enabled hdmi:

wlan0 IEEE 802.11 ESSID:off/any
Mode:Managed Access Point: Not-Associated Tx-Power=31 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Power Management:on



values with disabled hdmi:

display_power=0
wlan0 IEEE 802.11 ESSID:"myssid"
Mode:Managed Frequency:5.18 GHz Access Point: mymac
Bit Rate=121.5 Mb/s Tx-Power=31 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Power Management:on
Link Quality=46/70 Signal level=-64 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

display_power=1


1280x1024:
quality and level are very different here:
values with enabled hdmi:

wlan0 IEEE 802.11 ESSID:"myssid"
Mode:Managed Frequency:5.18 GHz Access Point: mymac
Bit Rate=108 Mb/s Tx-Power=31 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Power Management:on
Link Quality=38/70 Signal level=-72 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0



values with disabled hdmi:

display_power=0
wlan0 IEEE 802.11 ESSID:"myssid"
Mode:Managed Frequency:5.18 GHz Access Point: mymac
Bit Rate=108 Mb/s Tx-Power=31 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Power Management:on
Link Quality=47/70 Signal level=-63 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

display_power=1

EDIT: Update
2.4 GHz is affected the same way.

I downgraded the EEPROM to 00013701 and the 2.4 GHz and 5 GHz Wifi seems to be more stable.

popovvn
Posts: 2
Joined: Sun Apr 19, 2020 11:58 am

Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Sun Apr 19, 2020 12:12 pm

The same story.
WiFi 2.4 is slow, 5 — unusable with 1980x1080 HDMI plugged.
Bouth bands are o.k. with HDMI unplugged.
Even ping response reduces up to 10 .. 100 times.
The download/upload speed — respectively.
What a pity...

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mahjongg
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Sun Apr 19, 2020 9:59 pm

I understand that 1980x1080 generates interference with one of the 5GHz channels, but this can be solved by using a tweaked 1980x1080 resolution that doesn't cause interference.

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HawaiianPi
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Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Mon Apr 20, 2020 11:31 am

¯\_(ツ)_/¯ channel 157 (5785 MHz), width: 80 MHz, center1: 5775 MHz ¯\_(ツ)_/¯

Raspberry Pi 4 Model B Rev 1.1 (2GB).
Official Raspberry Pi 15.3W USB-C Power Supply.
2 layer open sided acrylic case with Noctua 40mm 5V fan.
HP Pavilion 27xw 1080p monitor (HDMI-0 > Monoprice micro-HDMI adapter and Ultra Slim Series HDMI cable).
Raspbian Buster with desktop (using the 64-bit kernel, recently updated).
With /boot on SD card and the root filesystem on a SATA-III SSD (Eluteng blue USB 3.0-SATA-III adapter cable).
ASUS RT-AC68U router at the end of the hallway (couple of rooms away).
Frontier FiOS ISP (100Mbps up/down).

Code: Select all

tim@RaspberryPi4B2:~$ uname -a
Linux RaspberryPi4B2 4.19.97-v8+ #1294 SMP PREEMPT Thu Jan 30 13:27:08 GMT 2020 aarch64 GNU/Linux

tim@RaspberryPi4B2:~$ iwconfig wlan0
wlan0     IEEE 802.11  ESSID:"LoloNET-5GHz"
          Mode:Managed  Frequency:5.785 GHz  Access Point: 4C:ED:3C:4D:5E:6F
          Bit Rate=351 Mb/s   Tx-Power=31 dBm
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=64/70  Signal level=-46 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

tim@RaspberryPi4B2:~$ iw wlan0 info
Interface wlan0
        ifindex 3
        wdev 0x1
        addr dc:a6:3c:4d:5e:6f
        ssid LoloNET-5GHz
        type managed
        wiphy 0
        channel 157 (5785 MHz), width: 80 MHz, center1: 5775 MHz
        txpower 31.00 dBm

tim@RaspberryPi4B2:~$ speedtest-cli
Retrieving speedtest.net configuration...
Testing from Frontier Communications (50.39.176.229)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by CenturyLink (Portland, OR) [14.30 km]: 12.798 ms
Testing download speed...........................................................
Download: 83.41 Mbit/s
Testing upload speed.............................................................
Upload: 75.75 Mbit/s
So, not as good as my Windows 10 laptop that's sitting on the same desk (95.95/100.22), but not terrible either, and pretty similar to what my 3B+ gets (86.44/74.88). I have noticed that a Flirc case affects the 4B WiFi much more than the 3B+ (which it barely affects at all). Not sure why, but if you have your 4B in a metal case of any kind, you might want to try it out of the case.
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Gecoul
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Joined: Thu Apr 23, 2020 9:58 am

Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Thu Apr 23, 2020 10:06 am

After some months of changing HDMI cables, cases and power supplies i think i did it.

My solution was to increase the router channel number. Channel 108 did the job here.

Chulamin
Posts: 1
Joined: Fri May 01, 2020 11:57 pm

Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Sat May 02, 2020 12:02 am

i'm not sure what OS you're using but I think the problem is with Raspbian. I have tried Ubuntu and Manjaro and even Android on the Pi 4B and 5G works great and is stable. I think it's a driver problem with Raspbian. I think a fix is needed.

popovvn
Posts: 2
Joined: Sun Apr 19, 2020 11:58 am

Re: Raspberry Pi 4b WiFi 5Ghz (ac) bugs

Sun May 03, 2020 6:47 am

Chulamin wrote:
Sat May 02, 2020 12:02 am
i'm not sure what OS you're using but I think the problem is with Raspbian. I have tried Ubuntu and Manjaro and even Android on the Pi 4B and 5G works great and is stable. I think it's a driver problem with Raspbian. I think a fix is needed.
I beleve You're right...
LibreELEC demonstrates good WiFi 5GHz on the same device.

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