The range of the signals depends on conditions, but in any case, they can be received only in the area served by an electricity substation.
Eight people have been killed trying to steal copper from electricity substations in the last year alone.
Opposition to wind farms in the county has grown since proposals were announced last year to build a 19-acre electricity substation.
During this period, the building at the top was disguised as an electricity substation through the appropriate signage.
You would find for example that electricity substations are distributed in far higher concentrations.
The youths had been chased by police and taken refuge in an electricity substation where they were electrocuted.
That' - he pointed at a circle outside the town of Wendover - 'is an electricity substation.
Plans for a controversial new electricity substation have been shown to a Powys community.
With just 30 minutes played of the match, the stadium was temporarily plunged into darkness caused by a fault at an electricity substation.
Operation Josephine B, a 1941 attack on an electricity substation.