I believe what imjolly is suggesting is that the Sky Q box forms part of their own mesh system and transmits on channel 36. If memory serves, that cannot be changed. This will be interfering with/interrupting the SH2 and the delay caused is behind the pixelation. The SH2 needs moving to channel 40, 44 or 48 to avoid this.
As far as 2.4GHz goes, to put a lot of history into a nutshell, when wireless first launched it was an industrial thing configured by techs that knew what they were doing. Then the home market took off and world, brother and dog got involved.
In fact, the only channels that do not overlap with other channels are 1, 6 and 11. In a crowded environment you are better to share a channel with your neighbour. There is a mechanism in place that allows two wireless units on the same channel to cooperate and share the channel, taking turns. If your neighbour uses, say, channel 6 and you use 8 they overlap and interfere but can’t hear each other clearly enough to cooperate, making matters worse for both parties. Consequently, you should stick to 1, 6 or 11 even if the other channels are available.
You will notice that at 5GHz the channels are already spaced four bands apart, 36, 40, 44 ,48.
