Sometimes information would have to be plotted that came from an external source, not normally part of the reporting chain; a fighter calling an SOS would report this through his radio on an emergency frequency, which would be picked up by the closest listening post.
Sometimes information would have to be plotted, not normally part of the reporting chain. This plotted came from an external source. A fighter calling an SOS would report this through his radio on an emergency frequency. An emergency frequency would be picked up by the closest listening post.