Netgear R7800 only getting about 140Mbps down - why so slow?

You might test my next master build (coming later today), as it will add the radio calibration fixes from dissent1 that are discussed in LEDE pull request https://github.com/lede-project/source/pull/1153 and originally in forum Netgear R7800 exploration (IPQ8065, QCA9984)