English: Bill Wallace operates the range and bearing controls of a GL Mk. III radar, by this time known as the AA No.3 Mk.4. Wallace is using the radar to track a weather balloon carrying a radar reflector, taking a measurement once every minute as timed by the stopwatch hanging from the top of the console. These measurements were then used to calculate the speed of the balloon at different altitudes, and thus determine the winds aloft. Surplus WWII-era Mk. III's was used in the meteorological role well into the 1950s.

This image shows the rightmost side of the operations console, where range was measured. The upper CRT, eye level, displayed everything within 32,000 yards of the radar. Turning the hand wheel set a bias control that moved a marker, known as the "strobe", along the upper display. A target was picked out by moving the strobe under its "ping" on the display. The lower CRT, just above the hand wheel, showed only the pings within the 6 microsecond strobe, of about 1.8 kilometres, allowing very accurate measurements. By slowly turning the wheel, the operator would keep the target blip lined up on a metal wire stretched across the face of the lower CRT, which can be just made out in this photograph. The range is then read off the dial to the right of the lower CRT.

Offscreen to the left are similar operator consoles for the bearing and elevation measurements. These stations had only one CRT, displaying only the target selected in the range operator's strobe, in the same fashion as the lower range unit. The location of the upper CRT was instead used for the measuring dials. Note the bearing control wheel, in the lower left, is much larger than the range dial. This is because the bearing was measured by rotating the entire radar antenna, mounted on a large pole.