[SOLVED] Startech USB433WACDB RTL8811AU blind to most 5GHz channels?

LordLovatt

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Mar 24, 2006
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Hi all, looking for some advice regarding a USB Wi-Fi adapter that is baffling me somewhat.

I have a Startech USB433WACDB USB 2.0 mini adapter which uses the RTL8811AU chip. It is rated for 802.11ac 5GHz.

For some reason, it only seems to be able to see channels 36 to 48. Anything after channel 48 and it acts like there's nothing there. Connects and works OK if I set my AP 5GHz channel to 36/48, but unfortunately there's a couple of neighbouring APs using the same channels, so I need it on channel 52 or above, which are clear in my area.

The AP is an old BT HomeHub 4 which I have repurposed as a dumb AP. Other 5GHz Wi-Fi devices can connect to this on channels 52+ no problem, in fact it works very well with them so I don't believe its an issue with this. The AP firmware does in fact warn of the 10 minute delay when changing to channel 52+, but my other Wi-Fi devices see the new channel in as little as 1 minute. It doesn't show up on the Startech adapter even after waiting 10 minutes.

I'm using a home-built Windows 10 64-bit PC, but have also confirmed the same behaviour with the USB adapter plugged into a Lenovo Windows 10 64-bit laptop, so I don't think it's a Windows thing. Also tried the latest driver from Startech/Realtek (they both seem to match) and it makes no difference.

Any ideas? Is this somehow by design?
 
Solution
It is even worse than that. UNII-2 generally you are not allowed to set the channel manually any place in this band. UNII-2 is many times broken into A and C. All these channels are subject to signal avoidance rules. They for example must stop using the band if they detect weather radar or other licensed use on these channels. Since most manufactures do not want to deal with this mess many routers do not support it. The ones that do the only way to use them is to set the router to auto. Even then many end device do not have the support.

The other commonly used band is called UNII-3. In has different rules for different countries but normally the channels are 149-165 and you are allowed to manually set them.

And if...

Ralston18

Titan
Moderator
How old is that Startech USB adapter? Does it get very warm or even hot (check carefully) while being used?

Overtime, such adapters (made as cheaply as possible) degrade and will exhibit problems including getting hotter than normal with use.

And that can be and is a "matter of design" and especially with respect to design EOL (End of Life). So "yes" to "somehow by design".

And other problems such as you describe can occur as well..

Try using a USB extension cable to move the USB adapter up and away from the host devices (Window 10 PC and Lenovo laptop).

Doing so may help with the adapters ability to receive and (perhaps more importantly) transmit. May also help with cooling.
 

kanewolf

Titan
Moderator
Hi all, looking for some advice regarding a USB Wi-Fi adapter that is baffling me somewhat.

I have a Startech USB433WACDB USB 2.0 mini adapter which uses the RTL8811AU chip. It is rated for 802.11ac 5GHz.

For some reason, it only seems to be able to see channels 36 to 48. Anything after channel 48 and it acts like there's nothing there. Connects and works OK if I set my AP 5GHz channel to 36/48, but unfortunately there's a couple of neighbouring APs using the same channels, so I need it on channel 52 or above, which are clear in my area.

The AP is an old BT HomeHub 4 which I have repurposed as a dumb AP. Other 5GHz Wi-Fi devices can connect to this on channels 52+ no problem, in fact it works very well with them so I don't believe its an issue with this. The AP firmware does in fact warn of the 10 minute delay when changing to channel 52+, but my other Wi-Fi devices see the new channel in as little as 1 minute. It doesn't show up on the Startech adapter even after waiting 10 minutes.

I'm using a home-built Windows 10 64-bit PC, but have also confirmed the same behaviour with the USB adapter plugged into a Lenovo Windows 10 64-bit laptop, so I don't think it's a Windows thing. Also tried the latest driver from Startech/Realtek (they both seem to match) and it makes no difference.

Any ideas? Is this somehow by design?
The allowed WIFI channels is different for different countries. You could have a driver that is most restrictive. Channels lower than 50 are allowed world wide. Above that varies by country.
 

LordLovatt

Distinguished
Mar 24, 2006
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18,530
Thanks for the replies all.

I managed to get ahold of somebody on Startech's live chat (impressive service) who very quickly pointed out that the device does not support the UNII-2 band or above, hence the restriction to Channels 36-48 in the UNII-1 band.

Fortunately I was able to swap it with a TP-Link Archer T2U from another device, which does support UNII-2.

Must admit I wasn't aware of UNII until today.
 
It is even worse than that. UNII-2 generally you are not allowed to set the channel manually any place in this band. UNII-2 is many times broken into A and C. All these channels are subject to signal avoidance rules. They for example must stop using the band if they detect weather radar or other licensed use on these channels. Since most manufactures do not want to deal with this mess many routers do not support it. The ones that do the only way to use them is to set the router to auto. Even then many end device do not have the support.

The other commonly used band is called UNII-3. In has different rules for different countries but normally the channels are 149-165 and you are allowed to manually set them.

And if you buy the very newest wifi6e stuff there are a bunch of new radio bands in the 6g range
 
Solution