use the carcinotron's own signal as the tracking source. If a single jammer is sending out a signal its location can be determined through simple triangulation by two stations by drawing the measured angles on a shared map. But if there is more than one jammer, each station will measure several angles and it is not easy to tell which of the measured crossing points contains the jammer aircraft. The introduction of the correlator introduced a way to eliminate this ambiguity. This concept was explored in a system known as "Winkle" that used two widely separated antennas, several correlators, and a computer to calculate the location of the jammer. It was later noted that one of the two antennas could be the Blue Riband, thereby reducing the number of new sites that had to be built. Winkle proved itself able to track the jammer even while it was below the radar horizon, allowing the aircraft to be driven off before it could approach close enough to be effective against Blue Riband. By 1957 a new network combining these systems was outlined under the name "Ahead". The system would cover the entire British Isles, like ROTOR and the Type 80s before it. Because the new systems had even longer range than Type 80, the number of stations would be smaller, with the baseline deployment having only five stations. A number of Type 80s would be retained in the new network purely for early warning, in locations were interceptions would not be taking place and the anti-jamming performance was not needed. Changing threats Prior to this period, the air defence mission in the UK was based on a damage-limitation model which aimed to reduce the amount of damage on the UK while inflicting losses on the enemy that would make follow-up attacks impossible. This sort of concept is best illustrated by the Battle of Britain, where the RAF was able to cause enough damage on the German bomber force that daylight raids had to be abandoned. Even in the post-war era with early nuclear bombs, this basic concept was still the prevailing strategic concept. The introduction of the hydrogen bomb rendered this concept useless. In this case, a single aircraft escaping interception could cause enormous damage. Estimating the number of bombers that would reach their targets, it appeared any such attack would result in the UK being devastated. In this environment, the