Inhaltsverzeichnis
P-700: PL39
Long wave direction finder P-700 / PL 39, LP, Telefunken P 111 N, manufactured by Telefunken.
The direction finder E383N was developed by Telefunken Berlin and was manufactured under licence by Telefunken Zurich, 26 stations were acquired from 1939 - 1945, threy remained in use until 1960.
Technical data
- Frequency range: 75 kHz - 3.6 MHz in 5 ranges
- Bearing accuracy: 3° minimum accuracy
Power supply
Dimensions
- Receiver case 354 x 370 x 220 mm, 23 kg
- Accessory case 21 kg
- Tripod in canvas bag 11.5 kg
- Frame antenna in canvas bag 7.3 kg
- Two field chairs 3.5 kg each
The entire station equipment (receiver case, accessory case, receiver mount tripod, direction finding frame antenna) has a weight of 69.8 kg
Accessories
- Z8N accessory case, containing bearing support with handwheel, bearing compass; plate batteries and heaters accumulator
- DF antenna: foldable frame DF antenna PR58N with rod auxiliary antenna
Operation
The E383N / EP2N direction finding receiver developed by Telefunken covers a frequency range of 75 kHz - 3.6 MHz.
The single conversion superhet receiver with an IF of 56 kHz is equipped with three RES094 and three RE084 valves.
It is powered by two 6 V (according to hamfu.ch: 4.5 V) NiFe heaters accumulators and four 30 V plate batteries.
A foldable PR58N frame direction finding antenna with a rod antenna as an auxiliary antenna is mounted on top of the bearing support of the set. One part of the frame antenna is used for direction finding, the second antenna frame positioned at a 90° angle and the rod antenna are used together as auxiliary antenna for lateral determination.
The direction finding system consists of the EP2N receiver case (23 kg), the Z8N accessory case (with bearing support & bearing scale, bearing compass, heaters and plate batteries, the Z7N tripod and the PR58N cross-frame direction finding antenna and has a weight of 69.8 kg with all accessories.
It was used as a portable or mobile unit mounted on a vehicle.
Technical principle
The E383N DF receiver is a single conversion superhet with an RF amplifier stage; it works on an intermediate frequency of 56 kHz. After the IF amplifier stage, a regerative stage is used for demodulation. The AF output stage only provides sufficient output power for headphones.
Tube configuration
V1 (RES094, RF preamplifier); V2 (RE084k, oscillator); V3 (RES094, mixer); V4 (RES094, IF amplifier); V5 (RE084k, regeneration); V6 (RE084, AF output amplifier)
Development
The P 111 N DF system was developed by Telefunken AG, Berlin, in 1932/33. The cross frame antenna can be used to take a bearing with one active frame as DF antenna, while the second frame mounted at a right angle to it and the rod antenna are used as auxiliary antenna for side determination.
Use
A total number of 24 long-wave direction finders 39 were acquired at a unit price of CHF 11,000.
The LP 39 / P-700 was used by Fk Kp 7, which was established in 1940 and was renamed Mot Fk Kp 20 in 1944, the DF receiver was decommissioned in 1960.
Deployment at Dübendorf airfield
In the instructional film 214 Flieger - Grenzbesetzung made by the Army Film Service, the LP 39 direction finder ican be seen in action in the control tower of the Dübendorf military airfield.
