Inhaltsverzeichnis
P-708
Long-wave direction finder P-708/m, Telefunken P 101 aN; developed by Telefunken AG, Berlin, manufactured by Telefunken Albiswerk, Zurich.
The long-wave direction finder P 101 aN 1938/9, was developed by Telefunken Berlin and manufactured under licence by Telefunken Zurich. The DF system was procured to be used in aircraft direction finding, i.e. to determine the location of an aircraft using a direction finding signal emitted by the aircraft.
The direction finding system consisted of a direction finding receiver E683N /EP2 and an additional listening receiver E417N / HE1 and was mounted on a light Berna truck.
Technical data
- Principle: Telefunken P101aN long-wave direction finding system
- Frequency range: 75 kHz - 3.33 MHz
Power supply
Dimensions
- mm, kg
Accessories
- Direction findung antenna: Cross-frame DF antenna PR6 with rod auxiliary antenna
Operation
Two receivers are used in the P 101 aN long-wave direction finding system: the E683N / EP2N direction finding receiver also used as standalone set in the P111N / P-700 station and an E417N / EH1 monitoring receiver as a second receiver, which is technically largely identical apart from the missing direction finding input section.
The single conversion superhet receiver with an IF of 56 kHz is equipped with three RES094 and three RE 084k.
The DF antenna used is a PR6 cross-frame antenna (Dübendorf museum has PR4) with a rod antenna as auxiliary antenna for side determination. The direction finding antenna is mounted on the roof of the DF cabin mounted on the Berna truck chassis and it can be rotated from inside by the operator. The frame position is transmitted to a vertical dial, from which the bearing angle can be read inside the truck.
Technical principle
The E383N DF receiver is a single conversion superhet with a RF amlifier stage and with an intermediate frequency of 56 kHz. After an IF amplifier stage, a regenerative stage is used for demodulation. The AF output stage has only sufficient output power for headphones.
Valve lineup
V1 (RES094, RF preamplifier); V2 (RE084k, oscillator); V3 (RES094, mixer); V4 (RES094, IF amplifier); V5 (RE084k, regenerative detector); V6 (RE084, AF output stage)
Development
Use
The four systems were ordered in 1937 and went into service in 1938; they were used to take external bearings from aircraft in order to determine it's position in conditions of poor visibility, the bearing was given pack to the pilot. Also instructions could be given to an aircraft approaching a military airfield. The DF systems were liquidated around 1960.
