Could probably do a scan to tell if 40MHz or 20MHz was better, but practically these devices are not used in areas with neighbors. The cool part was that our noise floor was great.
> It causes headaches practically everywhere it is used.
It really does - we got a few complaints that the latest iPhones took twice as long to sync as crappy Android phones. Not enough that I would choose differently on the next one, but something to consider.
The other wonky thing was that the usual channels 1/6/11 become 1+6 or 6+11, always up against guardband limits, but reducing power impacts bitrate across the entire bandwidth. Channel 4+9 didn't have this issue but overlaps with all 20MHz channels. I hear the newer WiFi specifications are better at managing this.
