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Router swapped to THG3000 and problems started (NOTHING else changed) speedtests on wired always around 33mbps. wifi 0.5 to 23mbps intermittent, not dependant on time of day. Inssider shows signal strength constantly dipping from -40 to -90. Router occassionally changed channel (can't do it manually on 192. as it's not an option any more, nor is splitting SSID) but never more than 1 other network on same channel. Line tested ok (of course as it's not the line). Because wired signal is ok Vodafone are saying there is no issue. Please help as vodafone won't.
First question has to be, why did you change to the THG3000?
Personally I have just put my THG3000 back on (same firmware as you) and surprisingly I have the ability to change channels back! (I'll attach proof as probably no one will believe me)
I'm surprised you said you can't split the WiFi as that option was always there for me.
I find the 5Ghz much better than the 2.5Ghz on the THG3000.
Positioning of the router can make a big difference so try that, if you haven't already.
Try doing a factory reset via the GUI and see it it changes anything (I suspect that a factory reset may have had something to do with the channel set options returning)
1. No channel number selection.
2. Cannot turn off Wi-Fi from browser, have to use button on router.