I can't say for certain why Roku supports some WiFi channels but not others. But the fact they aren't legal for use in some locations is a very likely reason. Actually, it isn't that DFS channels are illegal to use in some places (although there are places they are not permitted), but that even if they are permitted they still have restrictions on their use. And Roku likely doesn't want to mess with meeting those restrictions, so they simply don't support those channels.
For me it is a mystery why 5Ghz network was not discovered unless a Roku reboot was initiated. Any comments on this??
my repeater is connected to a RJ45 and set up as an access point. I have not checked settings to check channels and I am not sure if I can control those. TP-link RE305 v3 with 2021 fw works fine and Roku E 4k connects to its 5Ghz Wi-Fi network.
@Panos please clarify the issue you're having. You said the Roku requires a reboot to see 5 GHz, but then you say your Express 4K connects to the 5 GHz network. Is it a different Roku that has to be rebooted? Do you have different SSIDs on your 2.4 and 5 GHz radios?
Yes, you should have complete control of the settings in the TP-Link you are using as an Access Point. Things like channel, mode and other settings might be set to Auto, but you can set them manually.
I used to connect Roku to a 2.4Ghz network since my provider router supports only a 2.4Ghz network. then I relocated Roku to a different room.
Roku could only find a new 2.4Ghz network of other access point though the Wi-Fi extender had dual network support. 5Ghz could not be found until I did a Roku system reboot. No trouble since then.
OK, it sounds like it's working fine now. Might have just been a glitch, or some random interference that was initially blocking the signal.
@lrhoward7 Please include your Roku model numbers. Also, have you checked your router/modem to ensure a) the 5 GHz channel is turned on and b) the channel being used is either below 49 or above 148. I ask those questions because most 5 GHz radios are set on Auto select channel, and sometimes they will change their channel used to one of the DFS channels, which are unsupported by Roku. Any channel between 49-148 will not appear on a Roku device. Also, modems/routers under control of the ISP (most cable modems are like this, unless you purchased your own), they might make changes without your knowledge, not intending to break anything, but that can be the result if something is changed that impacts your connected devices.