SE-303: G3L

High power 3 kilowatt long wave station, G3L or SE-303; made by Telefunken, Berlin.

The high power long - wave radio station G3L (Grosse 3 kW Langwellenstation) was developed by Telefunken GmbH, Berlin, around 1932 and was handed over to the troops in 1934/36. A total of 6 stations were operated by the signal troops to provide command communication links between the Army command and the field corps on long-waves.

SE-303, transmitter and operators trailer

Technical Specifications

Power Supply

  • Generator: Three - phase generator (380 V, 50 Hz) to be powered from a petrol engine.


  • Transitter trailer: 6.20 x 2.25 x 2.80 m; 6000 kg
  • Radio operators trailer: 6.20 x 2.25 x 2.80 m; 4100 kg
  • Generator, loaded on truck; 1500 kg


  • Antenna material: The G3L / SE-303 was usually operated on a three-wire 80 m long T / L antenna, which was erected between two 22 m high masts, the space required for the station was 40 x 100 m.

Station Equipment

The long - wave wireless station G3L was developed by Telefunken GmbH, Berlin in around 1932 and handed over to the troops in 1934/36. A total of 6 stations were were acquired; the signalmen of the Schwere Funkerkp provided command communication using Hell teleprinters on long-wavesbetween the Army command and the field corps HQ.

Usually, the station was used in mobile operation. It consisted of a truck with the generator to power the transmitter (1500 kg), a two-axle transmitter trailer with the long-wave transmitting equipment (6000 kg) and another two-axle trailer with the receiver and Hellschreiber - equipment (4100 kg).

One station G3L had during the years of „active service“ in WW II a fixed installation in the „Funkerhaus“ („signals building“) in Bern, this fixed station of the army command was also used to broadcast regular Morse code training lessons.

Sender Spez 914Bs The three-stage transmitter Telefunken Spez 914Bs is tunable in four ranges by means of variometers, all tuned circuits are synchroneous. The antenna tuning is also done with wire - variometers.

In the transmitter, 20 tubes are used. In the driver stage a valve RS329g, in the intermediate stage one RS329g, and in the RF final stage another four RS329g, all final triods are grid modulated. The station has a maximum output power of 3000 W in CW telegraphy (A1) and 1000 watts in modulated telegraphy, telephony and Hell teleprinting.

The standard receiver was the Telefunken long wave receiver Spez 470Bs or E31. The three tuned circuit TRF receiver covers a frequency range of 100 - 1091 kHz in four ranges and is equipped with six RE074 neutro valves.
Later, the E31 was replaced by the autophone all-wave receiver E39. Empfänger Spez 470Bs

Technical Principle

Valve layout

Transmitter Spez 914Bs: six rectifiers RG49, six RS329g, one of each in the oscillator and driver and four in the transmitter output stage, five tubes RS237, three of them as keying tubes and two as modulator tubes, two RE084k in the modulator preamplifier, one RGN2504 to rectify the blocking voltage.
Receiver: see E31 and E39.


The development of the wireless station was done in 1932 at Telefunken in Berlin. The station was equipped as a novelty with the then state-of-the-art Hell - teleprinter, this transmission mode proved to be stable and reliable when used on longwaves, but not on shortwaves.

Field Use

The High Power Longwave Station was developed in 1932 at Telefunken, Berlin and six stations at a unit price of 228'000.- Fr. were acquired in 1934/36.

First, the G3L / SE-303 was operated by signalmen of the Fk Kp 27 and 28, later it was transferred to Lst Fk Kp and they were withdrawn and liquidated in 1961. Later the command communication between army command and the field corps was done by the remote controlled station SE-415.

Technical Manuals

Additional Informations

en/se-303.txt · Zuletzt geändert: 2019/12/08 09:18 von