R7800 very low download speed on 2.4GHZ(Solved)

[semsem]

Hello

I am running stock openwrt (OpenWrt 23.05.2 r23630-842932a63d / LuCI openwrt-23.05 branch git-23.306.39416-c86c256) and I have already switched from the ct wifi firmware to its non-ct counterpart but I still get very low download speed on 2.4GHZ. What is puzzling me is that even the upload speed is higher than the download speed. Here I am attaching screenshots comparison of speedtest between the 2.4 and the 5GHZ wifi.

[semsem]

Well I have just checked this option "Force 40MHz mode" in the advanced settings of the wireless 2.4GHZ settings and my issue has now been resolved as I get double the speed. I just hope there is no negative consequences for this option.

[semsem]

Well I thought my issue was resolved but despite the improvement in speed I am still puzzled why am I getting higher upload speed than download speed only on 2.4GHZ? My last speed test is 51 Down and 75 UP which does not make much sense to me as nobody is using the internet besides me and the 5GHZ measurement looks normal only the 2.4GHZ is abnormal to me.

[fakemanhk]

It's not a good thing to force 40MHz on 2.4GHz due to interference.
Upload faster than download isn't something new as well, you didn't download anything but how about other users in same area? Most people just download, and sharing the speed with you together.

[semsem]

It seems like this is an issue that affects many people. You can have a look here:

Slow R7800 2.4ghz transmits

I'm seeing the same issue across multiple R7800's: on 2.4Ghz, very slow TX speed from router but RX speed is reasonable. I don't see the issue on an Archer C7 v4 at the same router location (swapping between them). The R7800's 5Ghz speed is fine. Stock firmware 22.03.2 r19803-9a599fee93, default config. Archer C7 v4, client -> router (iperf3 -t 20 -c 192.168.1.1) Interval Transfer Bitrate 0.00-20.00 sec 73.0 MBytes 30.6 Mbits/sec Archer C7 v4, router -> client (iperf3 -t 20 …

[egc]

I have two R7800 (non-CT firmware) running 23.05 Snapshot from 4 weeks ago (routers are up for 4 weeks)

config wifi-device 'radio0'
	option type 'mac80211'
	option path 'soc/1b500000.pci/pci0000:00/0000:00:00.0/0000:01:00.0'
	option channel '116'
	option band '5g'
	option htmode 'VHT80'
	option country 'PA'
	option cell_density '0'
	option txpower '30'

config wifi-iface 'default_radio0'
	option device 'radio0'
	option network 'lan'
	option mode 'ap'
	option ssid 'Ls5_6'
	option encryption 'sae-mixed'
	option key 'XXX'
	option ieee80211w '0'

config wifi-device 'radio1'
	option type 'mac80211'
	option path 'soc/1b700000.pci/pci0001:00/0001:00:00.0/0001:01:00.0'
	option channel '3'
	option band '2g'
	option country 'PA'
	option cell_density '0'
	option txpower '30'
	option htmode 'HT20'

config wifi-iface 'default_radio1'
	option device 'radio1'
	option network 'lan'
	option mode 'ap'
	option ssid 'Ls24_6'
	option encryption 'psk2'
	option key 'XXXX'
	option ieee80211w '0'
	option disassoc_low_ack '0'

config wifi-iface 'wifinet2'
	option device 'radio1'
	option mode 'ap'
	option ssid 'R78002-iot'
	option encryption 'psk2'
	option key 'XXX'
	option network 'iot'
	option disassoc_low_ack '0'

My wifi 2.4 GHz spectrum is more or less clean as tested with Wifi analyzer on my Android phone S20

Channel width is 20 MHz as can be seen above , PHY rate of my S20 phone is 144 Mb/s, actual throughput as measured with Magic Iperf3 on my phone from another room about 20 ft away to a wired Windows PC running iperf3 is:
107 Mb/s download and 103 Mb/s up.
This is the expected maximal throughput (about 2/3 of PHY rate)

So perhaps your spectrum is not clean or your settings are not optimal.

[semsem]

Thank you so much for your post and for mentioning the Wifi Spectrum Analyzer app. My spectrum was indeed dirty and after changing the channels around now it is very clean and I get good speeds. I was really ignorant of this subject and I learned something new today thanks to you

[LilRedDog]

FYI OpenWrt has a channel analyzer: Status/Channel Analysis.

[egc]

But that only gives you information about the routers surroundings and not for the rest of your house/apartment.

that is why the wifi analyzer app on your phone is such a valuable tool

[egc]

If you are satisfied and have a working solution for your use case please mark that solution as solved:

How to mark a topic as [Solved]

Go to the very top of your topic, i.e. to your first posting Click the pencil behind the topic ===> If there is no pencil and you can not edit the topic title, skip this and jump to step #5 below. <=== [grafik] ===> If there is no pencil and you can not edit the topic title, skip this and jump to step #5 below. <=== Add "[Solved]" in front of the topic Click the checkmark to save the edit [grafik] If there is a specific posting that contributed the most to the solution, you can mark t…

[LilRedDog]

I love that app, don't get me wrong.