In June 1941, Brown visited the Army headquarters at Old Sarum Airfield to see if the RAF Army Co-operation Command's School of Army Co-operation might put radar to good use. The Army Co-operation squadrons carried out a variety of missions including artillery spotting, general reconnaissance, and ground attack. He found the group was only mildly interested in radar, thinking it might make a useful device for warning of the approach of enemy fighters, but were perfectly happy using flags and smoke signals for navigation and communications. Brown then visited a military exercise involving ground attacks in close coordination with the Army, and was convinced that radar systems could be used to improve these results. However, he also came to realize that almost all such missions would be carried out by aircraft of other forces, notably the RAF, so any system they proposed would have to be mounted in those aircraft.