OPi Lite WiFi @ armbian 5.13 - problem with 40 MHz channels

[vojtvop]

Hello,

 

my Orange Pi Lite WiFi (RTL 8189FTV) @ armbian 5.13 for OPi Lite works well on 20 MHz WiFi channels however is not usable on 40 MHz channels. The signal strength vary between 79 to 95 % on 20 MHz channel(s) while from -1 to 36 % on 40 MHz channel(s) and the connection is not possible. It seems the driver still needs some more tweak. Other WiFi devices have no problems with 40 MHz. The router I use to connect to is Asus RT-N18U (Broadcom BCM47081A0).

 

Thank you for your efforts

vojtvop

[Igor]

I think you are expecting too much from those chips. If your router uses standard firmware and you are living in urban area, this is not possible to achieve since router is closing second channel automatically if occupied.

 

On 2.4G (urban area) band is hard to achieve this even with "it should work" equipment.

 

Hard to say. Maybe someone gives you better answer with more details.

[vojtvop]

As I wrote, other devices have absolutely no problem with it. My smartphone at the place OPi is located shows router signal strength of -60 dBm and "clean air", while at the router location there are only networks with very weak signal (lower than -85 dBm) receivable. The problem is not that OPi can't use full bandwidth. The problem is OPi is not able to connect, so I must set router to 20 MHz or use another AP. If OPi could work for example in older 802.11g mode in these cases so it could communicate with the router in compatibility mode even when 40 MHz was set, it would be sufficient for me.

[jernej]

I found an interesting comment inside driver file core/rtw_mlme_ext.c

#if 0 /* Do not enable HT40 on 2 GHz */

I don't have any board with RTL8189FTV chip so I can't test if this makes any difference. You can test this by yourself by downloading driver from here, changing that to "#if 1" and compiling it. Please note that Realtek's drivers are not the best quality and they don't use Linux proven wifi stack but instead they implement their own.

[Igor]

And if this proves to be working, we will update the driver asap.

[Tido]

FYI

 

A message from 2012; (If Debian enabled MAC80211_DEBUG, then you can take a look at the map in /sys/kernel/debug/ieee80211/phyX/ht40allow_map.
It tells you which HT40+/- mode is supported at which frequency/channel)

# However, don't get your hopes up, because "According to 802.11-2012, APs and routers must default to 20 MHz bandwidth mode in the 2.4 GHz band.
# They may switch to 40 MHz bandwidth mode only after satisfying multiple criteria, including no "fat channel" intolerant bit set and no interfering APs.

# In addition, to meet spec, APs are not allowed to have a "40 MHz only" mode in the 2.4 GHz band

 

I also read, that many Router maker simply ignore this and activate 40MHz anyway.

[Igor]

I also read, that many Router maker simply ignore this and activate 40MHz anyway.

 

Also Armbian based AP

https://github.com/igorpecovnik/hostapd/blob/master/patch/300-noscan.patch