How to disable multiple spatial streams and Space-time block code (stbc)

[dancingbrave]

I'm trying to disable nss in ath9k driver and make the router to transmit in one single spatial stream. I found a tx_stbc flag and tried to set tx_stbc to 0, but it didn't work.

I'm wondering whether it will work if I set the supported_rates to only non-stbc rate and how I can set the supported_rates, like what rate list's pattern should be like.
Or are there any much easier way to achieve this? THX

[brada4]

You have to override capabilities (???_capab)
https://openwrt.org/docs/guide-user/network/wifi/basic
Compare with iw list and read descriptions.
https://w1.fi/cgit/hostap/tree/hostapd/hostapd.conf

[dancingbrave]

Thanks for your reply. And I've checked options in ht_cabap but there are no settings about spatial stram.

[brada4]

grep cap /var/run/hostap*conf
/var/run/hostapd-phy0.conf:ht_capab=[HT40+][LDPC][SHORT-GI-20][SHORT-GI-40][TX-STBC][RX-STBC1][MAX-AMSDU-7935]

Magic - remove these 2 repeating all others....

[TX-STBC][RX-STBC1]

[brada4]

Also if your intent is to make a long range link with one antennam the antenna mask does not work for quire a while, and HE (wifi 6 / ax) has separate capab set.

[dancingbrave]

Just curious, after doing so the wifi mode turned to legacy and I wonder if other functions specified by 80211n such as ampdu still working

[brada4]

How do you measure that?

[dancingbrave]

Measure wifi mode or ampdu? The wifi mode is shown by Luci web