I believe they were only missing in the EU version of the RT-N66U (which I had). John now allows them to be enabled with the wl_dfs_enable NVRAM variable (but in my experience, the N66U seems to be overly sensitive to radar detections compared to the AC68U).the higher ones in the DFS range do tend to occasionally disappear due to "radar detection" - John's fork fixes this by not having them enabled in the old driver!
This is the right answer....Different ssid's and forget the 2.4ghz ssid. Then they can't drop down to it.
also, you might want to turn the 5 GHz power up, and the 2.4 GHz power down...balance it out, in effect. Made a big difference for me, these 2 things. Now I have to choose between the bands when I get home - email/social media is 2.4 and DL/stream is 5Different ssid's and forget the 2.4ghz ssid. Then they can't drop down to it.
Welcome To SNBForums
SNBForums is a community for anyone who wants to learn about or discuss the latest in wireless routers, network storage and the ins and outs of building and maintaining a small network.
If you'd like to post a question, simply register and have at it!
While you're at it, please check out SmallNetBuilder for product reviews and our famous Router Charts, Ranker and plenty more!