I guess they picked the name "sub space" instead of ordinary sounding "space radio" maybe its a slight reference to side band radio.
And not to detour the topic, on utube I managed to run into free energy free wifi diy. Lots of spark plugs, wires, speakers and magnets. Its amazing how those spark plugs can make energy, we should all have a few wired up to get that free electron flow. Somehow on the internet there is a real magical confusion about what a spark plug can do.