Not only did Luftwaffe bombers use radio waves to find their targets, they were also used by fighters.
Knickebein or ‘crooked leg’ and X-Gerät were the Luftwaffe’s two famous systems for helping bombers find their targets. Fighters used the less well known Bernhard/Berhardine apparatus. Frank Dörenberg has studied Bernhard/Bernhardine extensively, discussing the system at length on his website.
We chatted to Frank about Bernhard/Bernhardine for our inaugural chainhomehigh podcast.
How it worked
Bernhard/Bernhardine had two components; a radio beacon on the ground and a printer in the aircraft. The beacon rotated through 360 degrees every 30 seconds. An aircraft within 80 nautical miles (150 kilometres) of the beacon received its transmissions.
When the beacon swept past the fighter, the fighter’s radio detected the signal. This activated the printer which turned the beacon’s coded signal into information.
Each beacon had its own identity code. By knowing the location of the beacon the fighter crew determined where their targets were. All they had to do was check the paper printout giving their position relative to the beacon.
Ground controllers gave the crew the location of the enemy bombers. The crew checked their position relative to the beacon. This allowed them to determine a vector to the bombers. Bernhard/Bernhardine could also help a fighter find a nearby airfield.
The Bernhard/Bernhardine system became more sophisticated as the war continued. For example, the radio beacon eventually transmitted data on the location of enemy aircraft.
Between 1941 and 1944 17 radio beacons were built across Germany and occupied Europe. Each beacon weighed at least 100 tonnes and was mounted on circular rail tracks with a diameter of 22.5 metres (74 feet). They could take six months to build and this slowed Bernhard/Bernhardine’s roll out.
The system was ahead of its time. Like today’s Link-11 and Link-16 tactical data links supporting naval and air operations, Bernhard/Bernhardine conveyed important tactical information except it was a ‘receive only’ system, unlike the tactical data links. That said, its legacy lives on today.