100 Watt Sender

L.S. 100/108 (Langwellen Sender 100/108)

Transmitter adapted for use in mobile command post. Circuit MOPA (master oscillator - power amplifier). Inductively tuned variometer coils; capacity type wave change system. Build on 3 assemblies - RF, LF and antenna tuning - fitted together by interconnecting lugs and sockets. Compartments of die-cast aluminum. Colors used liberally on dials and switches to indicate different bands. This set was originally used with the Spes. 445Bs receiver (obsolete); now used with the Torn.E.b. Manufactured by Lorenz. It may be known also as Type L.S. 100/108 (24v-108) in Lorenz commercial catalog and was developed before the war so that it could be quickly converted.

Translated from "Die deutschen Funknachrichtenanlagen bis 1945 - Band 2 "Der Zweite Weltkrieg" by Fritz Trenkle

In 1934 the Lorenz firm introduced the 100 Watt Transmitter S11375, also known as LS 100/108 = 100W.S./24b-108 (with different use designations). The frequency range was between 100 and 1200 KHz divided into four sections. It was built in two stages and was, as most radio devices built after 1931, calibrated by direct frequency measurement. A three-point circuit with variometer tuning of the built-in oscillator stage (using one RS-237) excited by the capacitive voltage elements of the power amplifier stage (2x RS-237 with parallel coupling), and the tuning variometer was in synchronized operation with the power amplifier. The antenna current is tapped between the 2nd variometer its series capacitor, and is tuned by way of double step-switchable antenna variometers. The A1 (telegraphy) keying is achieved in the oscillator stage, and the A3 modulation (voice) is achieved through the control grid of the power amplifier stage. The RS-241 serves as the modulation amplifier. This transmitter can use a wire antenna supported by a telescoping mast or a sectional mast, or a roof antenna of a radio vehicle.

Using A1 (telegraphy) operation, a range of 200 km (stationary operation) can be achieved, and 50-100 km can be achieved while moving. Filament heating voltage of 12 Volts is obtained from the vehicular battery. The anode voltage of +1000 Volts is obtained from either the U100 Umformer or from a small generator model C. This extremely reliable and easy to operate set was comprised only of two devices (transmitter and Umformer) and was loved by the soldiers who used it and was also widely found in civilian agencies (such as police and airport security). At these fixed installations a power rectifier unit was used instead of an Umformer. The infantry used the 100 Watt Transmitter mostly with the Torn.E.b receiver and the 10 meter sectional mast first in the light radio troop with the device designation "Fu 11 SE 100" for armored reconnaissance cars with the curved frame "Harp" antennas and telescoping masts. After 1937 a new designation was introduced in the "medium radio troops b = mittl.Fu.Tr.b". The variants with the "mittl.Fu.Tr.b" and "mittl.Pz.Fu.Tr.b/f"also carried an additional 15W.S.E.b. To reduce power consumption, sometimes the U100 was replaced with the U20, and the resulting range reduction was minimal.

0.2-1.2 MHz in five bands.



One 10-meter mast with 4-spoke umbrella (medium frequency) or one 6-meter sectional mast with 3-spoke umbrella (higher frequency). Roof masts were sometimes used.

(MO OR CRYSTAL) Mo. - self excited.



Mobile dynamotor U-100 or U-100a. Consumption 12 Volts dc at 30.8 Amps, output 1000 Volts at 240 mA. (speed 4000 RPM). Fixed gasoline-driven AC generator (consumption 12 Volts at 7.3 Ams, 1000 Volts at 240-300 mA).


100 Watts. (can be switched to provide 1/10 the output)


Two RS-237 triodes (M.O. and P.A.) and one RS-241 (speech amplifier); Both are directly heated Telefunken tubes requiring 12 volts.

Administrative control set for large areas. It can be used in vehicles or as a fixed station. Division command set use possible.

CW and Voice; Local and remote keying; Facsimile transmission.

CW 25-200; voice 10-70; The lower ranges are "on the mode"

Other sets within the same frequency range. Torn.E.b - all-purpose receiver -- and Lw.E.a are usually used as receivers. Type 80.W.S.c can be netted with it.


Armored command cars, half-tracks or communications trucks.


Front view of the transmitter. This one was built in 1937.



Mode selector and data plate.



The Lorenz logo and the antenna tuning mode indicator.



Antenna connector and current meter.



Voltmeter. Filament is 10 volts and anode is 1000 volts.



Power connection socket along with the keying relay, microphone and telegraph key connectors. The switch on the right toggles between full 100 Watt power to low 10 Watt power.



Frequency lock for the transmitter.



Pass-through antenna connector for the receiver.



The 100WS with the housing removed.



The huge antenna tuning coil. Many internal components are made from bakelite, to reduce internal capacitance and to lighten the weight of the transmitter. Notice the size of the antenna power feed tubes.



Waffenamt 506



Waffenamt 506



Some proof stamps and details of the feed tube.



More stamps and details of air core capacitors.



View from above the vacuum tube bay.



A 100WS being used around 1935.