Bomber crews already had some experience with these types of systems due to the deployment of the Lorenz beam, a commercial blind-landing aid which allowed aircraft to land at night or in bad weather. The Germans developed the short-range Lorenz system into the Knickebein aid, a system which used two Lorenz beams with much stronger signal transmissions. The concept was the same as the Lorenz system. Two aerials were rotated for the two converging beams which were pointed to cross directly over the target. The German bombers would attach themselves to either beam and fly along it until they started to pick up the signal from the other beam. When a continuous sound was heard from the second beam the crew knew they were above the target and began dropping their bombs.
The Germans developed the Lorenz into what system?
Knickebein

In 1983 the historic old town in the centre of Bern became a UNESCO World Heritage Site. Bern is ranked among the world's top ten cities for the best quality of life (2010).
When did the centre of Bern become the UNESCO World Heritage Site?
1983

Post-punk is a heterogeneous type of rock music that emerged in the wake of the punk movement of the 1970s. Drawing inspiration from elements of punk rock while departing from its musical conventions and wider cultural affiliations, post-punk music was marked by varied, experimentalist sensibilities and its "conceptual assault" on rock tradition. Artists embraced electronic music, black dance styles and the avant-garde, as well as novel recording technology and production techniques. The movement also saw the frequent intersection of music with art and politics, as artists liberally drew on sources such as critical theory, cinema, performance art and modernist literature. Accompanying these musical developments were subcultures that produced visual art, multimedia performances, independent record labels and fanzines in conjunction with the music.
What began to spring up around the post-punk music?
independent record labels and fanzines