At the summit there is a radar station that is operated by National Air Traffic Services and is a key part of the Air Traffic Control system for Northern England and Southern Scotland. A radome containing Primary Surveillance radar (PSR) and Secondary Surveillance Radar (SSR) antennas, various towers and fencing crown the summit. Alfred Wainwright abhorred the old radio station (removed in the 1980s) in his book Pennine Way Companion.
The construction of the radar station led to the repaving of a tarred road to the summit, which became Britain's highest road. This road is marked as private from just above the village of Knock, and not open to public motor vehicles. However, it is a bridleway until shortly before the radar station, so it is open to walkers, cyclists and horseriders.
Great Dun Fell Field Station
The University of Manchester formerly had a permanent meteorological observatory at the Great Dunn Fell site. It has hosted a number of field experiments doing research into clouds and their interactions with pollution. As the summit is in cloud for two thirds of the year it is an ideal location for this type of research. The university still has the option to use the site for short-term measurement periods.