Broadcast power is a method of delivering electricity, by transmitting it like radio waves from broadcast towers. Most of the robotic devices of the ancient cities function on broadcast power, though some (especially security and emergency service robots) have emergency power sources. A broadcast power station usually consists of a nuclear power plant to produce the power and a specially designed broadcast tower similar to a micro-wave relay tower. The broadcast range varies with the terrain, but 400 kilometers is the average.
Naturally, being prime military targets, few stations would survive the destruction of the Shadow Years. In areas where broadcast towers stopped working, robots that used broadcast power as a primary source would be forced to use their internal primary source until that runs out, or they loose the ability to recharge it. Activating a down broadcast tower would cause robots and discarded appliances (that have not been subject to too much decay or fallout) to spring to life.