- Broadcast receiver input switch of German Wired Broadcast
system (HF-Drahtfunk) of 1939. Allowed to connect broadcast
receiver antenna terminal to either outdoor antenna or the
Wired Broadcast signals coming from DWt 52 splitter.
be continued after the picture set...
idea of using telephone lines to deliver Long Wave radio
signals (150-300 kHz) was explored in Germany since
1924. The early system called "NF-Drahtfunk"
allowed to listen to just one program which would be
interrupted every time when external phone calls
March, 1939, the "HF-Drahtfunk" was implemented to
allow for up to three different broadcast programs to be
received over a telephone line on top of regular phone
calls. There were three standard frequencies in Long Wave band chosen for "HF-Drahtfunk" - 160, 210 and
German citizen could buy special splitting and switching
modules to install them at home and have a choice of either
regular radio or Wired Broadcast. The idea proved to be
especially useful by the last years of WW II when air raids
of English and American bombers to Germany became quite
frequent (Bombenkrieg) and German broadcast radio stations would suspend
their on-the-air transmissions not to serve beacons for the
approaching bombers. Under such circumstances, only those
civilians who had "HF-Drahtfunk" installed in
their homes could receive timely warnings about expected air
HF-Drahtfunk networks remained in use in Germany till
mid-1963 and in Swiss up to late 1990s (!!)
appreciation to Prof. Dr. Otto Kunzel for sharing and
correcting the above Drahtfunk information.