BBC:

morning on Brighton beach, and we are sitting on a slope of pebbles, looking out to sea. With us we have a laptop, several metres of cabling, and an antenna taller than a small child. In between waving off the attentions of men wielding metal detectors and some extremely large seagulls, we squint into the computer screen, looking for a specific peak on the radio spectrum. We are trying to see the invisible infrastructure that surrounds every part of our modern existence.