Ok - good to know that you are running C7 V2 firmware and having success with that setting. I did see @sammo's posts in another thread regarding 'ldpc', but I thought the hardware/firmware was slightly different, so I didn't actually try that particular tweak. At the moment, I actually have way better 2.4GHz coverage in the house using a separate AP located in another room which is connected back to the Archer by ethernet.