Last page update: 19 May 2017

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One of the Frequently Asked Questions that I used to get is: "Which radios did the German military use with the Hell Feldfernschreiber?" This page is an attempt to provide an answer. It primarily covers German military radios that are known to have been (or were intended to be) used in combination with Hellschreiber. I.e., there is documentary evidence (photos), or they have an explicit Hellschreiber interface (which, however, does not prove that they were ever used with a Hellschreiber). It is not my intention to provide an in-depth treatise on these radios, and the list may not be exhaustive. Undoubtedly, the Feld-Hell was used with other radios as well. Note that the title of this page is not "German military radios...." but just "Military radios...": the Feld-Hell was used by the military of several countries, often with their "local brand" radios.

It is important to note that the Feld-Hell was not intended for use with any particular receiver, transmitter, or transceiver. In principle, any radio suitable for fast CW (on-off keyed "Morse" telegraphy), AM, or FM communication could be used. FM modulation was used on UHF directional radio links, such as the "Michael" system. Feld-Hell does not appear to have been used with FM portable radios. Of course, had SSB radios been commonly available (see the "Performance" page), they could also have been used. During WW2, the Hell system was used with transmitters with an output power from several watts to 1 Megawatt! The radio range with Hellschreiber was similar to that of CW "Morse" telegraphy (ref. 1). Ref. 2A-2F provides a general overview of German military radios, 1920-1945.


Fig. 1: Communication range of several Wehrmacht transmitters and transceivers

(source: Fig. 54 in Chapter 8 of ref. 3)


Fig. 2A: one of the model-designator systems of Wehrmacht radios

(source: ref. 4)


Fig. 2B: another model-designator system of Wehrmacht radios

(source: ref. 4)

Note that the Kriegsmarine (German navy, 1935-45) used special Hellschreiber teleprinters that were built by the Hell company (models N2 and NS3). Both the Kriegsmarine and the Swiss army used "Presse-Hell" news-agency Hell printers.

The German 6th Army (with Axis forces) was surrounded at Stalingrad late November of 1942, and surrendered on 31 January 1943. It is sometimes suggested that the Feld-Hell was used as a "last resort" means of communication with the outside world. However, an estimated 90% of communication in and out of Stalingrad was done via Morse code telegraphy, and the rest via land-lines and UHF directional links (ref. 5B). Undoubtedly, units of the Wehrmacht Nachrichtentruppe (Signal Corps) in Stalingrad did have Feld-Hellschreibers, as this was standard equipment (ref. 5A). However, they were used for local communication.

The 6th Army included 20 Divisions. Each division hat its own Nachrichtenabteilung (Na-section). Note that the 6th Army had already gone through battles before getting stuck in Stalingrad. Had this Army been at the nominal strength for 1938/39, the combined Na-sections would have comprised 380 (!) large Fernsprechtrupps (both motorized and horse-drawn units) and 100 mid-size & small motorized Fernsprechtrupps. The combined estimated nominal amount of telecom equipment would have been significant (ref. 5B, 5C, 5G):

  • 60x 100WS transmitter
  • 60x LW.E.a receiver
  • 380x Torn.E.b receiver
  • 40x 20WS.d transmitter
  • 40x UKW.E.d receiver
  • 40x UKW.E.f receiver
  • 160x 5WS transmitter
  • 80x Torn.Fu.b1 transceiver
  • 80x Torn.Fu.d2 transceiver
  • 60x Fu.H.E.u receiver
  • 60x Fu.H.E.v receiver
  • 20x "Enigma" crypto machine
  • 80 radio trucks (lorries)
  • 20 trailers with a Ladesatz D power supply

Furthermore, there were numerous motor-generators, pedal-powered generators, battery chargers, also UHF directional radio link systems, and additional radio equipment in tanks, weather stations, and for air traffic control.

Several weeks after the Germans were completely surrounded, a partial "Sägefisch" station was flown in, as was probably a second 70 W transmitter. A complete station included a Siemens-Halske automatic encryption/decryption teleprinter machine T-52 ("Geheimschreiber", British codename "Sturgeon") and a 1 kW Lorenz transmitter of the "Ehrenmal" series. Ref.5B-5E. The "Sägefisch" system used triple frequency and dual rhombic-antenna diversity, and SSB modulation with partially suppressed carrier. It was highly dependable up to ranges of about 3000 km (ref. 5F). The 70 W and 1 kW transmitters were used at Army/Army Corps level, for communication with Army HQ.

Of course, there were also Na-units and their equipment at Army Corps and Army level. Add to that over 2000 motorized vehicles, 640 motorcyles (Krafträder), 140 horse-drawn vehicles, over 1000 horses, field kitchens, etc. After the war, the total amount of discarded equipment (incl. both German and Russian tanks, guns and canons, and assorted vehicles) was so large, that the Soviet government built a steel plant in Stalingrad, to process it all...

If you have any additional information about radios that were used with the Feld-Hell but are not listed here, or have better photos, please contact me!


One of the standard Feld-Hell radio configurations is with the portable and mobile 100 watt medium-wave station Fu 11 SE 100. Note that "portable" is relative: two or three pack animals (mules) were required to carry the radios and the power generator. Anyway, this radio set consists of a Tornister Empfänger b (Torn.E.b) receiver and a 100 Watt Sender (100 W.S.) transmitter. The set was used by the Army ("Heer"), typically in radio trucks ("Funkwagen") such as the Kfz. 17 and Kfz. 61, the mittlerer Kommandopanzerwagen / Funkpanzerwagen Sd. Kfz. 251/3 IV, the schwerer Panzerspähwagen Sd.Kfz.232 (ca. 70 km radio range), and the schwerer Panzerfunkwagen Sd.KFz.263 (ref. 7C). Ref. 7A describes the use of the Fu 11 SE 100 with the Feld-Hell by the Luftnachrichtentruppe (Luftwaffe Signals Corps).


Fig. 3: "Hellschreiber" is one of the of operating modes supported by the mobile 100 watt station

(source: ref. 7D)

The next figure shows a standard Luftwaffe interface configuration of the Feld-Hell with a 100 W.S. transmitter and a Torn.E.b. receiver. Both are AM and CW capable, but the equipment configuration below is for "AM" modulation. The "La - Lb/E" phone-line and "Empfänger" connector of the Feld-Hell are connected to the fax/Hell input connector of the 100 W.S., and the "Fernhörer" output connector of the Torn.E.b, respectively.


Fig. 4A: interconnection of a Feld-Hell with a "Torn.E.b." receiver and "100 W.S." transmitter

(source: ref. 1)


Fig. 4B: Feld-Hell, "Torn.E.b" and "100 W.S"

Lorenz 100 Watt Sender (100 W.S.)

The "100 Watt Sender" transmitter was developed by C. Lorenz AG in 1934, as a successor to several 20 Watt transmitters of C. Lorenz AG and Telefunken. The original model designator was LS 100/108 (Langwellen Sender - longwave transmitter). This was changed in 1936 to 100 W.S./24b-108 and finally to 100W.S. in 1938. In the earlier designators, "24b" refers to the Wehrmacht equipment sub-category ("Stoffgliederungsuntergruppe") of radio equipment ("Funkgerät"). The items in each equipment sub-category were numbered consecutively. The "Gerätnummer" of this radio is 108. Ref. 6C.

The transmitter opereates in the frequency range of 200 kHz to 1.2 MHz (longwave + medium wave), divided into four bands. This is compatible with the longwave receiver Langwellenempänger a "Anton" (Lw.E.a, 72-1525 kHz), with which it was commonly used, as well as Tornister-Empfänger such as the Torn.E.b.


Fig. 5: The "100 W.S."

(source: 6F)

Basic characteristics of the 100 W.S. are:

  • Frequency range: 200 - 1200 kHz, covered by 4 bands
  • Output power: 100 watt (10 W selectable in CW mode)
  • Vacuum tubes: 1x RS 241, 2x RS 237
  • Power supply options:
  • motor-generator converter (dynamotor "Umformer") type U100, U100a, or U100a1 powered by a 12 volt DC radio battery ("Funksammler") type 12B75 (75 Ah)
  • for 1000 volt DC anode voltage and 12 volt DC vacuum tube heater filament voltage.
  • generator type Kleinmaschinensatz c or c1
  • power supply type Netzanschlußgerät NA 8 in combination with an Elektromaschinensatz IV
  • transmitter rectifier unit Sendegleichrichter S.GL.T 100
  • Note: there was also as special version for 3-phase AC power.
  • Construction: 3-part die-cast chassis made of light metal alloy ("Elektron")
  • Size: 51x50x28 cm (WxHxD, ≈20x20x11 inch)
  • Weight (without the vacuum tubes): 33 kg (≈73 lbs)

Connecting the Hell Feldfernschreiber is very simple:


Fig. 6: instructions for connecting a Feld-Hellschreiber to a "100 W.S." transmitter

(source: 6A)

The "La Lb/E" phone line connector of the Feld-Hell machine is either connected to the special connector "Bildtelegrafie/Feldfernschreiber" of the 100 W.S. (located just above the "Mikr." microphone connector). When not used, a jumper is inserted into the latter connector. For AM ("Telefonie") transmission instead of CW ("Telegrafie"), the Feld-Hell's "La Lb/E" is connected to the microphone input of the 100 W.S.


Fig. 7: connector nr. 27 is for connecting a fax machine or a Feld-Hell machine (also see Fig. 8 below)

(source: ref. 6D)


Fig. 8: connector nr. 27 (shown with jumper installed) is for connecting a fax machine or a Feld-Hell machine

(source: ref. 6A)


Fig. 9: a "100 W.S." with "Kleinmaschinensatz C" generator and the "100 W.S. / Torn.E.b" range table

(source table: ref. 6A; range depends on which umbrella antenna or vehicle roof antenna is used)

A special keying device was available for the 100 WS. Tastzusatz Tz. (Fu) 100 WS. (ref. 6B). It comprised a fast keying relay: Siemens-Halske type T.rls. 54b (Bv 4/726). According to ref. 7B, remote keying could be achieved for distances of 3 km (≈2 mi) over regular "Feldkabel/Feldfernkabel" field phone lines, and up to 50 km (≈30 mi) over "Dauerleitung" permanent field phone lines. The same keying device was also used with the 15.W.S.b transceiver.


Fig. 10: patch cords and keying device of "Tastzusatz Tz. (Fu) 100 W.S."

(source: ref. 6B)

Tornister-Empfänger b "Berta" (Torn.E.b)

The Tornister-Empfänger b ("Bertha") is a direct-conversion receiver ("Geradeausempfänger"). I.e., the frequency of the local oscillator is the same as (or close to) the carrier-frequency of the signal being received. This is as opposed to a superhet (superheterodyne) receiver, in which detection is done after conversion to an intermediate frequency (IF).

The unit is housed in a carrying case ("Tornister") and is battery powered (both heater and anode voltage of the vacuum tubes). It was one of the most widely used receivers (at least an estimated 150 thousand units built!), and was used by all branches of the Wehrmacht. It was used in combination with the 5 W.S. (radio set Fu 9 / SE 5), 30 W.S., 80 W.S., and 100 W.S. transmitters. Ref. 2B, 7A, 7B.

The Torn.E.b was one of an entire series of new "Tornister" ( = backpack portable) radios that were developed during throughout the 1930s. Ref. 7C-7G. The Torn.E.b entered into service in 1937 to replace the Tornister-Empfänger model Spez. 445 Bs and Spez. 445 b Bs that dated back to 1931. Ref. 7G. Telefunken also marketed the Torn.E.b as a special receiver with the designator Spez. 976 Bs (ref. 7K, 7J). An export version of the Torn.E.b was developed in 1940. It has the designator Ae 1020, had an extended frequency range of 200 kHz - 15 MHz, and comprised vacuum tubes of type RV 2,4 P 700 rather than RV 2 P 800.


Fig. 11: the Tornister-Empfänger b (Torn.E.b)

Early models of the Torn.E.b were exclusively built by Telefunken (1937-39), later on also by Mende Radio, Saba, Sachsenwerk (in Dresden), Ostmarkwerke (in Prague-Gbell), and others. As the war progressed (1943), quality of the produced units declined. This was a general issue, not limited to the Torn.E.b. Increasing scarcity of raw materials and funds led to simplifications and modifications, such as elimination of the voltmeter (the mounting hole was covered by a metal plate), replacing the original light magnesium-aluminium alloy of the chassis and front panel with a 50% heavier zinc alloy, and reducing the size (and eventual elimination) of aluminium screening of RF sections.

Basic characteristics of the Torn.E.b are:

  • Frequency range: 97-6970 kHz, covered by 8 bands
  • Modulation: A1 (unmodulated telegraphy), A2 (modulated telegraphy), and A3 (telephony).
  • Vacuum tubes: 4x RV 2 P 800 (ref. 7K):
  • Power for the vacuum tubes:
  • Heater: 2 volt / 0.8 amps DC heater battery (model 2B38) or electromechanical DC-DC chopper/vibrator supply ("Wechselrichter" model E.W.b)
  • Anode: 90 volt / 12 mA DC battery
  • Size: 36.5x24.5x22.5 cm (WxHxD, ≈14x10x9 inch)
  • Note: the matching Tornister case for the batteries and some accessories had the same size. The Tornister of the Torn.E.b was clipped on top of the battery Tornister, to form a single Tornister. Hence, both cases are also referred to as Halbtornister "half cases".
  • Weight: 11.3 kg (≈25 lbs)
  • Note: the battery Halbtornister weighed 12 kg (≈26.5 lbs).

The video clip below shows Helge Fykse (LA6NCA) demonstrating one of his Torn.E.b. receivers:

Helge Fykse (LA6NCA) demonstrating a Torn.E.b receiver

Telefunken receiver Spez. 445

The photo below shows a "first generation" Feld-Hellschreiber connected to a Telefunken receiver of type Spezial 445 (Spez. 445), installed in a Funkkraftwagen radio truck. This receiver is the predecessor of the Torn.E.b described immediately above, and successor to the Telefunken E 266x receiver (ref. 7G). It was used in combination with, e.g., the 5 W.S. transmitter (radio set Fu 9 / SE 5), ref. 7P.


Fig. 12: Telefunken receiver model Spez. 445 (left) connected to a "first generation" Feld-Hell (center)

(source: ref. 7L)


Fig. 13: receiver model Spez. 445 Bs (left) and transmitter model 5 W.S.

(source: ref. 7A (Spez. 445) and ref. 7P)

The Spez. 445 entered service in 1932 (ref. 7P) and was built until some point in 1937. There were several versions, such as the 445 dBg (ref. 7N), 445 Bs and 445 b Bs (ref. 7M). The difference between the latter two is limited to the mechanical construction on the inside.

The receiver came standard with a shortwave ("Kurzwellen") frequency range of 2750-7500 kHz. As the tuned circuits of the receiver used air-wound coils (ferrite coil cores were not used yet), the coils were large. Covering other frequency bands required exchanging the coil set. Besides the coil set for "Kurz", there was an optional coil set for 500-3300 kHz "Mittel" ("Mittelwellen", mediumwave) for use with the 5 W.S.c transmitter (a.k.a. Spez. 469 Bs). For use with the 20 W.S. and 100 W.S. transmitters, there was a 100-1000 kHz "Lang" coil set ("Langwellen", longwave). Ref. 7N. These large coil sets ("Einschub mit Spulensatz") were plugged into the front of the receiver, see the oblong front panel with two frequency tables at the lower right-hand corner of Fig. 13 above.

This is a regenerative receiver - standard from ca. 1915 up to WW2. It uses a simple vacuum tube amplifier circuit with a positive feedback loop (re-generation). A gain control allows the operator to adjust the amount of feedback to the point just below or above the level at which self-oscillation occurs. The receiver's circuitry comprises four triodes of type RE 074 Neutron. The regular RE 074 was not to be used (unsuitable, per section III item 19 in ref. 7M). The "neutron" version was screened to tighter tolerances on the grid-anode ( = grid-plate) capacitance, heater current, and the oscillation operating point ("Schwingungseinsatz"). Heater voltage (at 250 mA) is provided by a 4.8 volt NiCad battery (Nickel-Cadmiumsammler 4,8NC10). Anode voltage is provided by a 90 volt anode battery (Anodenbatterie) at 8 mA. This battery has a 3 volt tap, for the grid-bias of the vacuum tubes.

The carrying case ("Tornister") of the Spez. 445 measures 36x47x23 cm (WxHxD, excluding the lumbar cushion on the back, ≈14x18.5x10 inch). The unit weighed 25 kg (≈55 lbs). Ref. 7M. The 5 W.S. basically had the same dimensions, and weighed 21.5 kg (≈48 lbs). It was also built in several versions: 5 W.S., 5 W.S.b and 5 W.S.c.

Kurzwellen-Empfänger a "Anton" (Kw.E.a)

Initially (1936-1941), the 100W.S. was used in combination with the Kurzwellen-Empfänger a (Kw.E.a "Anton") instead of the Torn.E.b. The Kw.E.a is beautiful super-heterodyne receiver that covers 980 kHz up to 10200 kHz with five bands. It has a single IF of 250.9 KHz. There is an RV 2 P 800 pentode vacuum tube (also used in the Torn.E.b) in each of the 11 stages of the circuitry. The radio consumes about 2.2 A at 2 volt for the tube filaments, and 20-25 mA anode current at 90 volt DC. The unit is battery powered, though a power supply model NA 6 can be used for the anode voltage. The unit is big: about 69x27x35 cm (WxHxD, ≈27x11x14 inch). It is also rather heavy: 42 kg (≈93 lbs), despite the die-cast chassis and front panel being made of lightweight "Silumin" aluminum-silicon alloy. Ref. 8A. This is a true "boat anchor" radio!


Fig. 14: the "Kurzwellen-Empfänger a" (Kw.E.a)

(source: on-line auction, 2015)


Fig. 15: two Feld-Hell stations with KwEa (or LwEa) in a Wehrmacht radio room

(source: © Fastner Collection/Sammlung; used with permission)

The KwEa was also part of the Wehrmacht's Sägefisch IV multi-channel radio teleprinter system with automatic encryption/decryption capability. This system (unlike earlier Sägefisch versions) also included a Hell Feldfernschreiber (Siemens-Halske model T.Typ.58):


Fig. 15B: KwEa receiver and Feld-Hell were part of the "Sägezahn IV" system

(source: ref. 8B)


The "Fahrbare 30-Watt-Mittelwellen-Station" is a mobile 30 W medium-wave transceiver set. It comprises the 30 Watt Sender (30 W.S.) transmitter and the Mittelwellen-Empfänger b (Mw.E.). It was intended for operation with a Hell Feldfernschreiber:


Fig. 16: operating modes of the "30 W.S." - telegraphy, telephony, and Hellschreiber

(source: ref. 9)


The 30 W.S. 24b-120 is a medium-wave transmitter that covers 950-1670 kHz; note: the 30 W.S.a covers 1120-3000 kHz. Its modulation modes are A1 (unmodulated CW telegraphy), A2 (modulated CW telegraphy), A3 (AM telephony), and A4 (Hellschreiber). Output power is 30 watts in A1, and 12 watts in A2-A4. The Telefunken commercial designator for this model is "Spez. 657 A". The circuitry comprises five tubes of type RS 241.


Fig. 17: the 30 W.S. transmitter

(source: ref. 9)


The Mittelwellen-Empfänger b / 24b-312 (Mw.E.b) is a superhet medium-wave receiver that covers the frequency range of 580 - 2000 kHz. The corresponding Telefunken commercial designator is E 434 A. It comprises six vacuum tubes of type RV 12 P 4000. Ref. 10A.


Fig. 18: the Mw.E.b receiver

(source: ref. 10A)

Note: the Mw.E.b is not to be confused with the Mw.E.c "Ceasar" (though actually more correctly "Walter"). The Mw.E.c comprised twelve vacuum tubes of type RV 12 P 2000. Like the Mw.E.a, it never entered into service. Ref. 10B.


There are several high-power transmitters that

  • The Wehrmacht "1 kW-Kurzwellensender" 1000 W.S.b (also 1 kW W.S.b) shortwave transmitter. Ref. 11A. It was manufactured by both Telefunken and Lorenz AG.
  • This is the military version of Telefunken's S 521 Bs transmitter. Ref. 11D, 11E
  • The Wehrmacht "1.5 kW-Langwellensender" 1500 W.S.a long-wave transmitter. Ref. 11F.
  • This is the military version of Telefunken's S 366 Ba transmitter. Ref. 11B.
  • The transmitter of the large 1.2 kW mobile shortwave station G1,2K (C-Station, SE-302) of the Swiss Army and the Swiss Air Force Radio Corps (Fliegernachrichtentruppe). The Swiss military acquired 16 of these units. They were built during WW2 (1940/41) under license from Lorenz AG, by Standard Telephon & Radio AG in Zürich/Switzerland. They remained in service until the 1960s. Note that the G1,2K station did include a Hellschreiber printer and sender, but the civil "Presse Hell" system rather than the military Feld-Hell.

These transmitters were developed ca. 1935-1936. The table below shows that they basically have the same design, so I have decided to group them. Another reason to do so, is that they are visually identical (other than the frequency scale).


Fig. 19: comparison of the 1 kW, 1.5 kW, and 1.2 kW transmitter

The associated manuals provide instructions for connecting a Feld-Hell machine and state "Hellschreiber" as one of the operating modes:


Fig. 20: instructions for connecting the Hell-Feldfernschreiber to a 1 kW or 1.5 kW transmitter

(source: §50 in ref. 11C)


Fig. 21: "Hellschreiber" is one of the operating modes of the "S 521 Bs" / "1000 W.S.b"

(source: ref. 11E)


Fig. 22: interfaces include Hellschreiber

(source: ref. 11D)

The next photos show the identical look of these transmitters:


Fig. 23: the fixed-base version of the 1 kW "S 521 Bs"

(source: 11E)


Fig. 24: the mobile version of the 1.5 kW "S 366 B"

(source: 11D, 11E)


Fig. 25: the mobile version of the "1 kW S.b"

(source: 11A)


Fig. 26: the 1.2 kW transmitter of the Swiss "G1,2K" mobile shortwave station

(the support-legs are for installation between the wheel wells of a radio truck, i.e., above the rear axle)


Fig. 27: the drawer with the transmitter keying circuitry

(2 tubes of type RS282 for negative-bias keying of the RS239 tubes in the PA; the "wheel" knob is for selecting the modulation/keying mode)


Fig. 28: the RS239 tubes of the final amplifier stage - glowing nicely during transmission

The transmitter could be installed in a radio truck version of the ubiquitous Kraftfahrzeug Kfz. 72. that was built from 1934-1942. The Kfz.72 was based on a 3-ton 3-axle Henschel type 33 "all terrain" truck chassis: Fahrgestell des mittleren geländegängigen Lastkraftwagens, offen (m. gl. Lkw. (o)). The D1 33 had a 6 cylinder gasoline (UK: petrol) engine. There were at least five different types of communication trucks based on the Kfz. 72:

  • Fernschreibkraftwagen (Fernschr. Kw.) - teleprinter truck
  • Fernsprechbetriebskraftwagen ( Fsp. Betr. Kw.) - telephone truck
  • Funkbetriebskraftwagen (Fu. Betr. Kw.) - radio operations truck
  • Funkhorchkraftwagen a (Fu. Horch Kw. a) - radio intercept truck A
  • Funkkraftwagen a und b (Fu. Kw. a & b) - radio truck A/B


Fig. 29: the Kraftfahrzeug "Kfz. 72"


The Telefunken 15W.S.E.b is the 15 Watt Sende-Empfänger (transmitter-receiver) model version b. This radio, including the antennas, is also referred to as "Fu 19" (FuG 19 SE 15). It was used by the infantry, and could be installed in armored vehicles. It covers the 3000-7500 kHz frequency range in two bands. The circuitry comprises nine tubes of type RV 2,4 P 700 (eight of which are in the receiver) and three of type RL 4,8 P 15. ref. 7B, 12A-12F.

VEF logo

The 15W.S.E.b was manufactured by Telefunken at the VEF factory (Valsts Elektrotehniskā Fabrika, State Electrotechnical Factory) in Riga (Latvia, starting in mid-1941 (ref. 15W-8). This company was founded in 1887 as the Russian subsidiary of the Berlin-based Union Elektrizitätsgesellschaft (UEG). UEG was absorbed into the AEG consortium in 1904/1905. The subsidiary became state-owned around 1919/1920, when Latvia became (temporarily) independent of Russia. At that time, it was renamed to "VEF", and then to "AEG Ostlandwerk GmbH" during the German occupation. Ref. 12C.


Fig. 30: operating modes of the "15W.S.E.b" - telegraphy (A1), telephony (A3), and Feld-Hellschreiber

(source: ref. 12G)


Fig. 31: the "15W.S.E.b" transceiver

This transceiver has a dedicated connector that is marked F.F Schreiber (for "Feldfernschreiber"), or just Schreiber. The connector is located at the lower left-hand corner of the front panel, just above the ground lug. Note that the 15W.S.E.a (built by Telefunken in Berlin, starting 1939) does not have this connector!


Fig. 32: the input connector for the Hell Feldfernschreiber

This connector is for transmitting Feld-Hellschreiber signals. For Hellschreiber transmission, the mode switch of the transceiver is to "F.F Schreiber", see photo above. The tone-pulses from the Feld-Hellschreiber are rectified. The resulting DC-pulses are used to key the modulator tube (Rö7 in the schematic), which is configured as a tone oscillator during Hell-transmission. See the simplified schematic below, the detailed schematic of ref. 12G, an the description on p. 17 of ref. 12G. During Hellschreiber transmission, the heater voltage of the tubes in the receiver is turned off (see the switch in the lower right-hand corner of the schematic below). For reception, the mode switch is set to "Empfang Tg" (Telegraphy reception).


Fig. 33: principle schematic for Feld-Fernschreiber transmission

(source: ref. 12F)

The transceiver is housed in a "Tornister" backpack carrying case that measures 34x42x22 cm (WxHxD, ≈13.4x16.5x8.7 inch). The set weighs 19.5 kg (≈43 lbs). Size and weight are similar to that of the Hell-Feldfernschreiber. The Tastzusatz Tz. (Fu) 100 WS remote keying device of the 100W.S. transmitter is used between the output of the Feld-Hell and the 15W.S.E.b.


The Telefunken T 9 K 39 "Main" is a superhet shortwave receiver that covers the 1.5 - 25 MHz frequency range with 8 bands. It was primarily used in U-boats and coastal stations of the Kriegsmarine.

As the type designator suggests, it entered into service in 1939. The "9" in T 9 K 39 indicates the number of tuned stages: 3 HF-stages, each with an RV 12 P 2001 pentode, a mixer stage with an RV 12 P 2000, two IF stages (RV 12 P2001 and RV 12 P2000), a detector, AF, and a BFO stage, each with an RV 12 P 2000. The unit is big and heavy: 55x29.5x33 cm (≈22x12x13 inch) and 45 kg (≈99 lbs). The unit has an IF crystal filter with a continuously variable bandwidth (100 Hz - 5 kHz). The frequency scale is displayed via rear-projection of a microfilm onto a small frosted glass plate. Many features of T 9 K 39 have been employed later in the famous Telefunken E 52 and E 53 receivers. ref. 13A, 13B.

The unit has two audio outputs: one with a 10 volt amplitude for a high-impedance headset, and one with 1 volt amplitude, for a Hellschreiber or an external audio amplifier.


Fig. 34: the Telefunken "T 9 K 39" receiver


The Telefunken E52 "Köln" was one of the four receivers that were intended to cover the 40 kHz to 150 MHz frequency range. Ref. 14A. These radios were specified in 1939. Initial production of the E52 started in 1942, and full production in 1943. The E52 is the shortwave ("Kurzwellen, hence the "K" in "Köln") receiver for 1.5 to 25 MHz. It was primarily used in fixed-based and mobile stations of the Luftwaffe. The equivalent Kriegsmarine designator is T 8 K 44. It is an evolution of the Telefunken T 9 K 39 "Main", with improvements and simplifications. Ref. 14B-14G.


Fig. 35: the Telefunken "E52" "Köln"

This is a fully modular radio. All modules are fully RF-screened, and all modules plug into a special backplane module that connects all other modules. The chassis is die-cast light metal. Mechanically and electrically, this is probably by far the most elegant and beautiful receiver of WW2. Construction and performance was far ahead of its time, and unequalled by Allied radios through the 1960s. Due to extensive temperature compensation, the free-running oscillator has exceptional stability. Like the T 9 K 39, it has a rear-projection frequency scale with a microfilm. Each unit had a "personal" microfilm that was specific to the frequency characteristics of that particular individual receiver. In total, ten RV 12 P 2000 pentodes are used in the various receiver stages (except the power supply). Also like the T 9 K 39. it has a crystal IF filter with variable bandwidth. Ref. 14H. Some ten variations of the E52 were developed. The differences are primarily related to manual and motorized tuning. The latter was another electro-mechanical achievement: frequencies could be memorized mechanically, and be recalled - with enough accuracy (about 50 Hz) to not need manual re-tuning.

The E52 has two audio outputs: one for a high-impedance (4000 Ω) headset, the other for a standard phone line (600 Ω). A special high-power audio output module was foreseen, for driving a Hellschreiber:


Fig. 36: special high-power AF final-amplifier module for driving a Hellschreiber ("Presse Hell")

(source: ref. 14A)

With this special module instead of the standard audio output module, the radio was model variant "E52d". There is no documentary evidence that this special module was ever designed, let alone produced.


Fig. 37 "Köln" model "E52d" was to include the Hellschreiber AF final-amplifier module

(source: ref. 14B)

It is unclear for which type of Hellschreiber the special audio output module was intended. In principle, Hell Feldfernschreiber can be driven by the loudspeaker output of any radio receiver. In fact, it needs a signal with a minimum amplitude of only 18 mV. The E52 does not have a loudspeaker output. I do not know the signal level at the phone-line output, but it is probably around 1 volt. So, the special module may actually have been intended for driving the solenoid of a "Presse Hell" printer: 20 mA at about 30 volt.


The type designator T 200 FK 39 tells us this is a 200 watt transmitter made by Telefunken, for Kurzwellen (Fernverkehr), i.e., long-distance shortwave. FK covers 6-30 MHz; the T 200 FK 39 covers 3 - 23 MHz. It entered into service in 1939. It was suitable for installation on board of ships. It was standard equipment on Kriegsmarine U-boats that operated in the south Atlantic and Pacific. This is yet another mechanical masterpiece, with excellent performance, notably extreme stability of the free-running oscilator. Ref. 15A, 15B.

Four operating modes are selectable: modulation types A1, A2, A3, and "TBS": Typenbildschreiber, i.e.., Hellschreiber. Note: this only applies to T 200 FK 39a and T 200 FK 39b, and not to the initial T 200 FK 39.


Fig. 38: position "TBS" of the BAW "Betriebsartenwahlschalter" (operating/modulation mode selector)

(source: 15A)

Above, the "tragbaren Typenbildschreiber" refers to the portable Hell-Feldfernschreiber ("Feld-Hell").


Fig. 39: operating modes (modulation types) of the "T 200 FK 39"

(source: 15A)


Fig. 40: the "T 200 FK 39" tower (power supply not shown) and the priciple schematic

(source: 15A)


The Ha 5 K 39 is a shortwave transceiver that was developed and built by the company Hanseatische Apparatebau-Gesellschaft ehemals Neufeldt und Kuhnke GmbH (Hagenuk) in Kiel/Germany (a major navy port). Until 1936, the company was simply named Neufeldt & Kuhnke, founded in 1899. This radio entered service with the Kriegsmarine in 1939, where it was widely used on (small) ships, in land stations, and vehicles of motorized signal corps units ("motorisierte Marine-Nachrichteneinheiten"). Towards the end of WW2, it was also used on conscripted merchant ships. The Radione company in Vienna/Austria built the unit under license. Ref. 16A, 16B, 16-C, 24C-2.


Fig. 41: the Hagenuk "Ha 5 K 39c" shortwave transceiver

It is a relatively compact desktop transceiver (52x35x24 cm, ≈20.5x14x9.5 inch; 22 kg, ≈48 lbs). All versions of this radio (Ha 5 K 39, 39a, 39b, and 39c) support the standard modulation modes A1 (5 watt), A2 and A3 (1.5 watt). Model 39 and 39c cover a frequency range of 3 - 6 MHz, whereas 39a and 39b cover the range of 2 - 5 MHz. All vacuum tubes are of type RV 12 P 2000, except for the RL 12 P 10 power pentode in the transmitter's final amplifier, and a GR 150/A voltage stabilizer.

In models 39b and 39b, both the transmitters final amplifier tube and the modulator tube can be cathode-bias keyed with a Feld-Hellschreiber. In Hell-transmission configuration, the keying-relay is continuously energized and the cathode of both tubes is biased "off" with a large resistor to ground. This resistor is bypassed by the keying contacts of the Hellschreiber. During Hell-transmissions, the modulator only serves as sidetone generator.


Fig. 42A: description of the transmitter keying in Hellschreiber mode


Fig. 42B: instructions Hellschreiber hook-up and transceiver operation

(source: ref. 16C)

One of the connectors in the lower left-hand corner of the front panel, there is a 3-prong keying input for a "Morse" telegraphy key ("Taste") or a Hell-Feldfernschreiber (Typenbildschreiber, T.Bild-Schr.):


Fig. 43: keying-input connector and mode-selection for a "T.Bild-Schr." (Typenbildschreiber = Hellschreiber)


The very rare Hagenuk Ha 15 K 42 is a shortwave transmitter (3 - 6 MHz) with an output power of 15 watt (A1 modulation; 5-6 watt in A2/A3) that entered into service in 1942.


Fig. 44: front panel of the Hagenuk "Ha 15 K 42"

(source: www.cdvandt.org)

Like the Ha 5 K 39, the Ha 15 K 42 has a keying input on the front panel, for connecting a Hell Feldfernschreiber. The "BAW" operating mode selector switch has separate positions for Hellschreiber transmission ("T.-Bild S") and reception ("T.-Bild E"):


Fig. 45: Hellschreiber transmit & receive mode selection and Hellschreiber keying input

Also like the Ha 5 K 39, all vacuum tubes are of type RV 12 P 2000, except for the power pentode in the transmitter's final amplifier. However, here, an LS 50 is used, rather than the RL 12 P 10.


The Lorenz Lo 70 KL 40, also referred to as "Marine-Kleinfunkgerät" and "Marine Gustav", was used for ship-to-ship and ship-to-shore communication in the Kriegsmarine. It covers both long-wave (300-600 kHz) and shortwave (1.5-7.5 MHz, covered by three bands). The set comprises a transmitter-receiver (separate modules in a single case) and an antenna coupler unit. The receiver comprises 7 stages, with ten vacuum tubes of type RV 12 P 2000 in total. There is a separate IF for long-wave and shortwave. The transmitter comprises three tubes of type LS 50. Output power is 70 watt (A1 modulation) or 40 watt (A2/A3). Overall size is 81.4x44x36.7 cm (WxHxD, 32x17x14.5 inch), with a weight of 76 kg (≈167 lbs). Ref. 18A.


Fig. 46: left to right - receiver, transmitter, antenna tuner/coupler

The connector block on the front panel of the transmitter has separate connectors for Hellschreiber transmission ("Typenbild-Send.") and reception:


Fig. 47: connectors for Hellschreiber transmission & reception are on the front panel of the transmitter

(source: Yuri Desyatnik)

The manual (ref. 18A) lists Hellschreiber transmission and reception as two of the five operating modes, as well as suitability for operation with a Hell-Feldfernschreiber:


Fig. 48: operating modes of the 'Lo 70 KL 40"

(source: ref. 18A)

The output to the Feld-Hellschreiber is simply connected in parallel with the headset output. In Hell-transmission mode, the transmitter is basically keyed just like in the "Morse" telegraphy mode: the keying contacts of the Hell-Feldfernschreiber directly (i.e., without a keying relay) key the suppressor grid of the three transmitter tubes, by pulling the +400 volt grid-blocking bias to ground. Note that this implies that one side of the connector is permanently connected to +400 volt - do not touch!


Fig. 49: simplified schematic of the transmitter configuration in Hell-transmission mode

(source: Fig. 7 in ref. 18A)

The radio was designed by C. Lorenz AG, in Berlin-Tempelhof, but built in occupied Czechoslovakia by the company Telegrafia, akc. spol., in Pardubice (ca. 130 km east of Praha / Prague). The company was founded in 1919, nationalized in 1946 and absorbed into the TESLA Narodny Podnik conglomerate. After 1945, the Lo 70 KL 40 continued to be made and used in Czechoslovakia, with the model designator "Jalta". Ref. 18B.


Fig. 50: the "Telegrafia" factory in Pardubice


The Telefunken AS 59 transmitter was intended for mobile (ship board and vehicles)as well as fixed-base installations. It covers the 2.5-20 MHz shortwave frequencies with 6 bands. Output power of the AS 59 is 200 watt (A1 telegraphy) or 50 watt (A2/A3). It was often used in combination with the Torn.E.b. and Kw.E.a receivers.


Fig. 51: the Telefunken "AS 59"

The front panel has a keying-input connector for a Hellschreiber:


Fig. 52: "AS 59" interfaces - with Hellschreiber keying input ("Hell-Taste")

Hellschreiber transmissions can be done both in CW mode (A1, unmodulated telegraphy), and A2 (modulated telegraphy) with the tone-generator that is built into the AS 59:


Fig. 53: title

(source: ref. 19A)

This radio was built under license by other companies in Germany, and in Switzerland. During the war, the AS 59 was also built in France, by Société Française Radioélectrique (S.F.R.), in their factory at Levallois-Perret near Paris. Over 1000 units were delivered to Telefunken. S.F.R. already had connections with Telefunken before WW2, and the S.F.R. sites (Levallois and Cholet) in occupied France were put under control of Telefunken during the war and produced Telefunken-designed equipment. Ref. 19C.


Fig. 54: equipment label of an AS 59 built by S.F.R. for Telefunken

(source: ref. 19B)

This radio was also used in the "Maikäfer" stations, to report A4-missile ("V2") launches and trajectories to headquarters. Ref. 19D. Germany sold a dozen of these sets to Spain in 1943. Ref. 19E.


The As 60 transmitter was initially built on a small scale in 1943 by Telefunken in Germany. Then it was built under license by Autophon AG in Solothurn/Switzerland and exported to Germany. This continued until sometime in 1944 (!), when the Allied nations were finally successful at forcing Switzerland to stop supporting Nazi Germany. At that point, Telefunken moved the production to a plant in occupied Czechoslovakia, some 160 km east of Prague. As a side-note: in general, license fees continued to be paid by US companies to German companies - and vice versa - via Switzerland, until well after the USA entered the war in 1943. Autophon also produced a derived model of the AS 60 transmitter for the Swiss army, as part of their motorized shortwave station M1K.


Fig. 55: two versions of the "AS 60"

(source: ref. 20A, 20B)

This shortwave transmitter covered the frequency range of 3 to 25 MHz with 6 bands. In A1 modulation mode (unmodulated "Morse" telegraphy), output power varied from 1.4 kW at the low frequency end, to 1.1 kW at the high end. There was a version of the AS 59 with only half that output power: it only had one instead of two RS 384 power vacuum tubes in the final amplifier. With A2 and A3 modulation, output power was only 300-350 watt (or 175 watt with a single RS 384). Hellschreiber transmission operation was done with either A1 or A2 modulation. In A2 mode, the Hellschreiber keyed a constant tone that was generated by an oscillator in the AS 60 itself ("Eigenton", selectable 800, 900, or 1100 Hz). The transmitter can also be keyed with tone-pulses from an external source. These are then rectified and fed to the keying tubes as a negative grid-bias, just like local tone pulses.


Fig. 56: modulation types supported by the "As 60"

(source: ref. 20A, 20B )


Fig. 57: remote Hellschreiber keying (i.e., over a distance of more than 1 km) is done with tone-pulses rather than direct keying

(source: ref. 20A, 20B)


Another shortwave transmitter of the Telefunken "AS" series is the AS 1008. This transmitter has an output power of 200 watt with A1 modulation, and 130 watt with A2 and A3. It covers the shortwave frequency range of 2.5 to 10 MHz. It was part of the mobile 200 watt station with provisions for Feld-Hellschreiber ("Fahrbare 200-Watt-Station mit Einrichtung für Siemens-Halske Hellschreiberbetrieb") installed in radio trucks. The receiver of the "200 watt station" covered 1.25 to 21.43 MHz.


Fig. 58: the "AS 1008" with power supply (left) and the mobile 200 W station with Feldfernschreiber (foreground) and an "AS 1008"

(source: ref. 21A )


Fig. 59: the 200 watt transceiver station with "AS 1008" transmitter supported Hellschreiber

(source: ref. 21A)


The Telefunken longwave equivalent of the above AS 1008 200 watt shortwave transmitter is the S 354 A (civil/commercial designator). Again, 200 watt with A1 modulation, and 130 watt with A2 and A3. the associated Telefunken long-wave/mediumwave receiver covered 75-1500 kHz


Fig. 60: the "S 354 A" transmitter supported Hellschreiber transmission

(source: ref. 22A)


In 1936/37, the light decimeter-equipment" Dezimetergerät 4a Klein(gerät)", or "DMG 4a K", was developed for the Luftwaffe. It was also known as "Michael II", and formerly known as "Richtverbindingsgerät K". This transmitter-receiver system worked with wavelengths of 54-60 cm = 5.4 - 6 decimeter, hence the name. This is equivalent to the UHF frequency range of 500-560 MHz. At these frequencies, the radio horizon is actually slightly larger than optical line-of-sight. Highly directional antenna systems were used.

The "Michael II" communications channel could be used for either a single voice channel (telephone or broadcast radio), or up to three simultaneous "two-tone" telegraphy/teleprinter channels. Transmitter output power was about 0.3 watt. Ref. 23G. It was the first UHF directional radio link system in which the transmitter-receiver and the associated AF part of the system were not collocated with the antennas. Instead, they were implemented as modules in an equipment rack, located up to 50 meters away from the antenna, via coax cable.


Fig. 61: title

(source: ref. 23A)

Hell-Feldfernschreiber communication was done with 900 Hz tone pulses via the voice channel, the same as over wired telephone lines:


Fig. 62: title

(source: ref 23A)

The documentation of subsequent DMG models such as DMG 5 K/aK and DMG 7 K/aK do not explicitly mention Hellschreiber operation. However, any communications channel suitable for voice/telephony, is more than suitable for Hellschreiber.

The map below shows the network of the Luftwaffe UHF directional communication links. Understandably, the network branches out from Berlin, with - at some point in time - an "orphan" sub-net towards Moscow.


Fig. 63: network of Luftwaffe "Michael" UHF directional radio relays (late 1942?)

There are sources that state that the UHF relay network with various models of "Michael" equipment, had a total combined length of 50 thousand or even 70 thousand km (about 30 and 44 thousand miles, respectively). The 70 thousand km total length may be a 1950s estimate from Telefunken, based on adding up all network "legs" that were ever built up, but were never all active at the same time. Note that the network "nodes" typically moved with the fronts as the war evolved. The 50 thousand km estimate is from a later date. It may reflect the maximum total network size that was active at any given time. Unfortunately, no records are known to exist that can be used to reconstruct and validate these estimates. Ref. 23C.

There are also statements and claims about the longest single end-to-end network path having a length of 5 or 7 thousand km. Based on the signal-to-noise performance of the UHF relays, such distances could only be covered with a combination of UHF relays and cables (or cable-only). Actual range of the relays was not explicitly specified. It was recommended not to exceed a total length of 300 km ( = five "hops" of 60 km each). Ref. 23D. Each UHF relay company ("Richtverbindungs-Kompanie") of the Wehmacht signal corps comprised twelve "Trupps". Each "Trupp" had one UHF transmitter and one receiver (plus mast with antennas), and could form one end-station or one relay station. Hence, at company level, a stretch of about 400 km could be covered.

Note that in the Luftwaffe as much as 80% of communication was via radio relays, whereas in the Heer (army), about 80% was via wired lines.


The Kriegsmarine used the Hell-system with an LF/VLF transmitter that was absolutely gigantic, both in terms of size of the antenna system and output power. It was appropriately named Goliath, and was used for world-wide broadcast to (submerged) submarines. In its time, it was by far (!) the most powerful vacuum tube transmitter with tunable frequency: up to 1 Megawatt at 15-60 kHz. Ref. 24A-1/2/3/4/5/6/7/8/9/10.

Goliath had the following operating modes:

  • CW ("Morse") telegraphy: 15-60 kHz (primary frequency: 16.55 kHz).
  • Hellschreiber: 30-60 kHz
  • Voice/phone: 45-60 KHz; voice quality was rather low, probably due to the very small bandwidth of the very-high-Q antenna system. With the same modulation, Hellschreiber could be operated down to 30 kHz, at which the bandwidth was too small for voice transmission.

CW and Hellschreiber messages could be sent in combination with the famous Enigma encryption system (ref. 24E-1, 24E-2).

The 15-60 kHz frequency range was used because it provides world-wide coverage, and these radio signals penetrate seawater sufficiently to reach submerged submarines. Penetration depth ("skin depth") depends on factors such as transmitter power, antenna efficiency, and seawater properties (salinity, temperature, density,...). Ref. 24D-3. For instance, at the primary Goliath frequency of 16.55 kHz, the following ranges (measured from Berlin) and depths were achieved consistently (ref. 24A-3, p. 247):

  • 8-12 m (≈25-40 ft) depth in the Golf of Aden (8200 km, ≈5100 mi) and near Cape Town (9300 km, ≈5800 mi)
  • 8-25 m (≈25-80 ft) depth throughout the North Sea and across the northern Atlantic to New York.

Note that at even lower radio frequencies such as 0.1 kHz (i.e., in the ELF range), depths of 300 m (1000 ft) can be reached.

Submarines that operated in those parts of the world were equipped with a dedicated LF/VLF receiver, notably the Telefunken Langwellen/ngstwellen Peilüberlagerungsempfänger ( = LF/VLF direction-finding radio with BFO) model T 3 P L Lä 38 from 1938, and an associated loop antenna, steerable with a hand wheel. It covered the frequencies of 15-33 kHz and 70-1200 kHz. Ref. 24B-2, 24B-3.


Fig. 64: the Telefunken "T 3 PL Lä 38" VLF receiver (far right) in a U-boat radio room

(source: Fig. 283 in ref. 24A-12)

Below are parts of some radio documents from the German submarine U-505, from November 1943, January and February of 1944. These strips reference transmission times and frequencies of Goliath. U-505 was captured intact by the US Navy off the Atlantic coast of northwest Africa in June of 1944. It is on display at the Chicago Museum of Science and Industry.


Fig. 65: radio documents from the German submarine U-505, with "Goliath" frequencies & transmission times

(source: ref. 24B-1; US gov't - no ©)

Note that most other high-power LF/VLF transmitters of that era still were enormous machine-generators. I.e., the continuous carrier frequency was generated electro-mechanically, without radio tubes. Most notably is the Alexanderson alternator, dating back to the early 1900s. Ref. 24A-10, 24A-11. The only surviving Alexanderson transmitter is located at Grimeton (near Varberg, in Alexanderson's home country Sweden). It is still operated twice a year (on Alexanderson's Day and at Christmas) on 17.2 kHz, with the callsign SAQ. The UK also operated powerful transmitters, but not in the VLF/LF frequency range; e.g., a 600 kW medium wave transmitter for jamming and propaganda broadcast purposes (ref. 24A-13, 24A-14).

The telegraphy speed of Goliath's Hellschreiber communication is unknown. As a reference: today's US Navy VLF/LF (14-60 kHz) installations use a 50 Bd transmission speed. Above 45 kHz, Goliath was suitable for low-quality voice/phone transmissions. This is quite adequate for transmission of Hell-pulses at 2.5 chars/sec (122.5 Bd = Feld-Hell), and probably even for 5 chars/sec ("Presse Hell"). For Hellschreiber transmissions, the modulator of Goliath transmitter was in the same configuration as used for AM voice/phone transmissions. That is: Hellschreiber tone pulses were used, rather than on-off-keying of Goliath in CW mode. Between 30 and 45 kHz, the bandwidth of the Goliath system was insufficient for voice communication, but usable for Hellschreiber.

The Goliath antenna and transmitter installations were located just outside the town of Calbe-an-der-Milde (Calbe on the river Milde), about 135 km (≈85 mi) west-northwest of Berlin, and ca. 65 km (≈40 mi) north of Magdeburg. In 1952, Calbe was renamed to "Kalbe", to avoid confusion with the town of Calbe-an-der-Saale (Calbe on the river Saale), ca. 30 km south of Magdeburg. The location was primarily selected because of the properties of the local soil being unusually conducive to VLF propagation. Construction of Goliath took 27 months, and was completed during the spring of 1943. Allegedly, construction of the installation (terrain, buildings, antennas, etc.) may have cost as much as 15 million Reichsmark. The transmitter was developed and constructed by C. Lorenz A.G. of Berlin-Tempelhof. Lorenz became part of the American company International Telephone and Telegraph (I.T.T.) in 1930. In 1948, the name was changed to Standard Elektrik Lorenz (SEL). Goliath was never the target of Allied bombing raids - very likely because the Allies enjoyed eavesdropping on the (encrypted) messages of the Kriegsmarine.

Goliath was remote-controlled from what today would be called the C3 (command, control, communication) center of the Kriegsmarine. This center, code name "Koralle", was located just north of Bernau, some 20 km northeast of Berlin. Ref. 24C-1/2/3. The Oberkommando der Kriegsmarine (OKM, Supreme Command of the Navy) - including the Befehlshaber der U-Boote (BdU) Grand-Admiral Karl Dönitz - had been moved here in January of 1943, due to the increasing risk of bombing raids on Berlin. The location of the (fully destroyed) C3 bunker at "Koralle" is marked on this map (Dönitz's villa is still there). Ref. 24C-3. Goliath was linked to "Koralle" (145 km away, ≈90 mi) via the communication network of the Wehrmacht. The Reichspost had put the required transmitter-keying and phone lines in place in 1942. Note that tuning of the transmitter and antennas was not remote-controlled. Goliath was hooked up to the public electrical power network ("Fernleitungsnetz"), with diesel generator backup. Goliath had the BdU callsigns ÄDA and DÄP, as did the BdU transmitters at Nauen (ref. 24B-2).


Hein Lehmann logo

Hein Lehmann logo

The 15-60 kHz operating frequency range of Goliath is equivalent to a wavelength range of 5-20 km (≈3-12 mi). This implies very large antennas. The Goliath "antenna farm" comprised three top-loaded monopole antennas (TLMAs), spaced 800 m (½ mi). They are sometimes referred to as a variation on the 1920s Alexanderson-antenna (ref. 24D-2). The monopole antennas of Goliath were 204 m tall (≈670 ft), about 2/3 the height of the Eiffel tower. Each of these antennas was a zinc-plated steel tube-mast ("Stahlrohrmast") with a diameter of 1.7 m (≈6 ft). The base of each tube-mast was insulated from ground with two large porcelain insulators, each with a large metal collar. This provided 300 kV isolation even during rain. This approach was patented (ref. 24D-7) by Hein, Lehman & Co., Eisenkonstruktionen, Brücken- und Signalbau of Berlin-Reinickendorf, incorporated in 1888 (sheet metal, steel constructions, bridges, railway signals, hangars for "Zeppelin" dirigibles). Ref. 24D-4. This company had a department ("Abt. Funkbau") that constructed and installed (very) large antenna masts and towers ("Funkmaste", "Funktürme"), primarily for Telefunken. E.g., the Funkturm (radio tower) in Berlin-Charlottenburg (1926), the antennas for the Langwellensender at Lahti/Finland (1928), at Nauen/Germany, Kootwijk/The Netherlands, and Sidney/Australia.


Fig. 66: porcelain-insulator base of one the "Goliath" tube-masts

(source: ref. 24A-1)

The Goliath antenna radiator of 204 m is quite large compared to human scale, but extremely small (≈1%) with respect to the wavelength of Goliath transmissions (5-20 km!). This gives the antenna a large capacitive reactance at the feed point. To counteract this, and increase antenna efficiency, the antennas were equipped with an enormous top-loading "hat" ("Dachkapazität") at the top, and a very extensive ground system. Each radiator had a hexagonal "hat" comprising six sets of six radial wires. The radial wires of the Goliath "hats" were aluminium cables (2.5 cm (1 inch) diameter), strengthened with a steel cable at the core. Combined length of the radials was about 50 km (≈31 mi). These wires look like the ribs of an umbrella. Hence this type of antenna is also called an umbrella-antenna ("Schirmantenne").

Umbrella antenna cartoon

Fig. 67: a real umbrella antenna!

(source: Radiobote, Vol. 5, Nr. 27, May-June 2010, p. 20)

Each of the the antenna radiators had a variable tuning coil. These coils were enormous variometers, comprising a fixed coil with a diameter of 3.5 m (≈11½ft). A slightly smaller coil (3.2 m diameter) could be inserted hydraulically into this stationary, with a precision of 0.1 mm! The coils were 5 m tall (16 ft) and weighed about 5000 kg (11k lbs). The main tuning coil, similarly massive, was housed in the transmitter building. A frequency change was a two-man job, and took about 5 minutes.


Fig. 68: side and bottom of an antenna tuning coil (one for each of the tube masts)

(source: ref. 24A-2)

To support the radials of the top-loading "hat", there were six truss-masts (lattice masts, "Gittermast") for each of the three radiator masts. By sharing support masts, their total number was reduced from 18 to 15. The truss-masts were 170 m (558 ft) tall, and had a triangular cross-section with sides of 3 m (≈10 ft). These masts were grounded and had no RF function. The radials were also insulated from these masts. All tube- and truss-masts were stayed with guy wires at three heights and in three directions. This type of antenna was later also used for VLF long-distance radio navigation systems such as OMEGA and LORAN-C.

The antenna system included an extensive of system of buried ground radials. There were four sections of 204 radials each. According to the Lorenz company, the total length of the radials was at least 350 km (≈220 mi; ref. 45). Other sources mention as much as 465 km (according to the construction supervisor, architect R. Breither, this may have included feed lines; ref. 24A-1. The radials were made of zinc-plated steel bands (20 cm x 2 mm and 30 cm x 2 mm), at a depth of 30-40 cm. At this point in the war, copper had become scarce. Solder joints were zinc-plated with a mobile galvanizing unit. To increase the effectiveness of the ground radials, the soil was kept moist. There were ditches and a dozen ponds that served as water reservoirs for irrigation. Ref. 45.

The complete antenna system had a very (!) impressive efficiency: 47% on15 kHz, and as much as 90% on 60 kHz.


Fig. 69: diagrammatic top view of the three umbrella-antennas


Fig. 70: Left-to-right - "Antennenhaus" (22 m tall building) with tuning coils, tube-mast, and main buildings

(source: ref. 24A-2; foreground: anchor of one of the guy wires of a tube-mast)


Fig. 71: central buildings (antenna feed lines exiting the roof) with rail access; cooling tower on the far right


Fig. 72: view from a tube-mast, down to a truss-mast 34 m (≈100 ft) below; (right) base of one of the 15 truss-masts

(source: ref. 24A-2)

The fenced-in area of the Goliath ""antenna farm" had the shape of an equilateral triangle, with sides of about 2.4 km (≈1.5 miles). The surface area of 2.63 km2 (260 hectares) is equivalent to about 320 regulation soccer fields or 490 US football fields! The image sequence immediately below shows the terrain, the location of the three main masts, an overlay of the umbrella antennas, and some dimensions.


Fig. 73: the "Goliath" site - overlaid with location of the antennas and the transmitter & control building

Below is an interactive map with the same 18 antenna mast locations. Locations marked with are exact. Click on any marker icon to get the associated information. You can click-and-drag the map with your mouse, and zoom in & out with your mouse-wheel (or use the buttons in the top left-hand corner of the map). The position of the truss-masts is marked with ; their exact location cannot be determined in the satellite image, except for the one marked with .

Fig. 74: satellite image of the "Goliath" site, with marked location of the 18 masts

(source: click here for a larger view of this map in a separate window.)


The Goliath transmitter comprises a modulator ("Steuersender") and a 3-stage power amplifier ("Hauptsender"). Only Telefunken vacuum tubes were used. The modulator has three tubes: RL 12 T 15, RL 12 P 35, and RS 384. The modulator had an output of 500-600 W. The first stage of the amplifier has two RS 217 tubes (of which one configured as a standby spare), the second stage has six tubes of type RS 250 (of which two as standby spares), and the final stage has six tubes of type RS 301 (ref. 24D-1). The latter six are arranged as parallel push-pull pairs. Ref. 24A-1. These tubes were water-cooled, stood 1.9 m tall (≈6.3 feet), and weighed about 90 kg (≈200 lbs). Ref. 24D-5, 24D-6Cooling was provided with distilled water, at a minimum flow of 48 m3 per hour (≈12 thousand US gallons/hr). Maximum capacity was twice that. Via heat-exchangers, the dissipated heat was transferred to a second cooling system (tap water) with two cooling towers.

The first and second stage were Class-B push-pull amplifiers. The final stage was operated with Class-C anode modulation for CW transmissions, and with Class-B anode modulation for voice/phone and Hellschreiber tone pulses. Ref. 24A-1, 24A-2, 24A-4. In CW mode, when the transmitter was not keyed "on", half of the six tubes in the final stage acted as dummy loads. This was done to avoid large fluctuations on the regional public power grid. Otherwise lights in the region would blink in the rhythm of the Morse characters. The maximum output current of the transmitter was 2500 amps, which was equally distributed to the three antennas (700 amps each) and a central feed point (400 amps).


Fig. 75: the Telefunken RS 301 tube

(source: ref. 24D-1)

A single RS 301 cost 8400 Reichsmark (almost six times the annual salary of the average factory worker in 1937), making a six-pack as expensive as a "V2" missile. A complete set of tubes cost over 106 thousand Reichsmark (ref. 24D-6).


Fig. 76: the final stage of the transmitter amplifier, with RS 301 tubes

(source: ref. 24A-2)


Fig. 77: the transmitter and control room in the central building

(source: ref. 24A-2)

Electrical power was provided by the three-phase 50 kV regional power grid, first reduced to 15 kV with local transformers. Two dozen AEG mercury-vapor rectifier tubes of type S15/150i (also water-cooled) were used to rectify the AC power. Backup power was provided by an 1800 kVA AEG generator, powered by a 2110 hp MAN diesel engine.

Goliath was never the target of allied bombing raids (just like the U-boats that served as worldwide weather reporting stations, and most factories that belonged to US consortiums such as Ford and I.T.T.). Intercepted and decoded messages provided invaluable information about U-boat command and the location of U-boat packs. It was also used as a navigation landmark.

The table below list some other high-power transmitters that were for transmissions to U-Boats:


Fig. 78: some other transmitters used by the Kriegsmarine for communication to U-boats (ca. 1943)

(source: ref. 24A-12)


The US army reached the Goliath site on 11 April 1945. They used it as a prisoner-of-war (POW) camp (ref. 24A-8, 24A-10). Towards the end of May 1945, it was handed off to the British. Based on the Yalta Treaty, the area was in the Soviet-controlled zone, and the Soviets took over at the beginning of July 1945. The POW-camp was dissolved at the end of that same month. The Soviets had the Goliath installation repaired and tested. It was fully dismantled by April 1947 and shipped to Russia in over 3000 (!) rail wagons. By 1952, it was rebuilt near Druzhnyy, about 18 km south of Gorky (some 150 km east of Moscow, and renamed Nizhny Novgorod (= "Nizhny Newtown") in 1990). The Druzhnyy area presumably has similar soil conditions as at Calbe. It is still operated to this day (2016) by the Russian navy, who use it for communication with submarines (surprise!) and to transmit time signals (station RJH99).


Fig. 79: Goliath - rebuilt at Druzhnyy in Russia

(source: 24A-2)

A satellite image of the current Goliath site is provided below.

Fig. 80: the current site of "Goliath" with marked location of the 18 masts

(click here for a larger view of this map in a separate window)


During the latter half of the 1930s, the Swedish army evaluated the Feld-Hell in combination with the following transmitter-receiver stations (ref. 25D-25J):

  • 10 W Br m/39 ("10 watts bärbar radiostation m/39"), portable transceiver (2.5-5.0 MHz transmit, 1.3-6.1 MHz receive, CW/AM). Ref. 43.
  • 30 W Kr m/29 ("30 watts kärr-radiostation m/1929") mobile radio (1.5-3.0 MHz transmit, 0.3-3.0 MHz receive, A1/A2 modulation)
  • 100 W Ft m/38 ("100 watts fast radiostation m/38").

Per ref. 25A (p. 47), the Swedish army used the Feld-Hell ("Hellskrivapparat" or "Hellskrivare") with the following radio sets:

  • 75 W Tp m/43 (ref. 25B) with transmitter type 100 B made by "Standard Radiofabrik", a "mottagarlåda" receiver box with two receivers of type MKL 941 (ref. 25L) made by Svenska Radioaktiebolaget in Stockholm (SRA, 1919-1983, in 1983 Ericsson Radio Systems AB), two 6 volt DC 85 Ah batteries, a 1500 W 50 Hz power generator, and antenna material. The transmitter is directly keyed by the Feld-Hell character drum. This system remained in use (though without Hellschreiber) until the early 1970s!
  • 250 W Bl m/40 and 250 W T m/40 ("250 watts bilradiostation", ref. 25B). This is a 1.3-9.0 MHz radio truck. The transmitter was operated with Hell tone-pulses via the microphone input. Ref. 25H. Output power: 250/110/75 W (A1. A2, and A3 modulation, respectively). The receiver was, again, the MKL 941 ,.Antenna: 6m mast + 2.6 m rod.
  • 800 W Bl m/43 ("800 watts bilradiostation", ref. 17). This is a 2.3-9.0 MHz radio truck, with a receiver for 200 kHz - 10 MHz. In Hell-mode, the CW transmitter was operated via a keying device. Ref. 25B, 25C, 25J. Transmitter output power: 800 watt (A1), and 200 watt (A2/A3). The transmitter covered 2.3-9 MHz. The four receivers (all model MKL 940), covered 200-400 kHz plus 540 kHz - 10 MHz (ref. 25L).


Fig. 81: transmitter (left) and receivers of the "250 W Bl m/40" and "250 W Bl T m/40" mobile stations (radio trucks)

(source: ref. 25B)

The Feld-Hell entered service with the Royal Signal Regiment of the Swedish Army in 1942. Wired operation was over military communications networks and the public telephone system. Their Sats Tc 33 Feld-Hell set (initially army stock number ( = Mtlrnr) Tc 90240, later M3963-105211) came complete with two 12 volt DC / 85 Ah battery packs. An attenuator (Tc 21115) could be plugged into the Siemens keying-device (army stock nr. Tc 20033, later M3936-105219), to reduce the output signal to a level that was compatible with the phone system. Ref. 25D.

Commercial negotiations between Siemens and the Swedish Air Force about Feld-Hell machines and "Presse Hell" type office equipment (5 cps), date back to ca. 1941 (see pp. 119-120 in ref. 25C). Pricing information for the Hellschreibers of the Swedish army and air force and the Swiss army, is provided on the "Hell equipment prices 1937-52" page.


During World War 2, Finland was involved in two armed conflicts with the Soviet Union: the Winter War (November 1939 - March 1940), and the Continuation War (June 1941 - September 1944). During the Continuation War, the headquarters of the Finnish armed forces was located in the town of Mikkeli - 180 km northeast of Helsinki. The headquarters were located in the buildings of the Central Elementary School, whereas the Communications Center was located in a cave in the nearby Naisvuori hill. The Center's codename was "Lokki" ( = seagull). Both sites are now a museum (here and here). The Communications Center maintained a Hellschreiber link with the the German forces in the town of Rovaniemi, 670 km to the north of Helsinki, in Finnish Lapland. Rovaniemi was headquarters of the Wehrmacht in Finland, December 1940 - December 1944. Ref. 26A, 26B, 2. Rovaniemi became one of the nodes on the 4500 km long German wired teleprinter / telephone network from Rastenburg (Kętrzyn) in Poland, to Berlin and Hamburg, via Denmark, Oslo and Narvik in Norway, Petsamo, Rovaniemi and Helsinki in Finland, Reval in Estonia, to Riga in Latvia. Ref. 26C.


Fig. 82: one of ca. 50-150 Feldfernschreiber operators of the women's' auxiliary services in Finland, 1941-1944

(source: courtesy T. Ekko, used with permission)

The first ten Feld-Hell machines entered service with the Finnish Defense Forces at the beginning of 1941. Many more were bought after that. Hellschreiber communication was primarily conducted over telephone lines, though the Finnish navy also used Feld-Hell in combination with the VRJP radio set. The Finnish Defense Forces used Feld-Hell until the early 1970s. Ref. 26D.

The four-digit equipment designator "VRJP" stands for: V = Viestintälaite (communications equipment), R = Radio, J = ???, P = the manufacturer (here: Philips) or country of manufacture. The VRJP set is either a DR 38 A or an FR 38 A transceiver. Both were made by Philips in The Netherlands. Or rather, they were designed and made by Nederlandsche Seintoestellen Fabriek (NSF) in Hilversum/The Netherlands. This company was founded in 1918, as a joint venture of Philips, Marconi U.K., and Nederlandsche Telegraaf-Maatschappij Radio-Holland. Philips became the majority shareholder of NSF in 1925 by acquiring the Radio-Holland shares, and bought out Marconi in 1946.


Fig. 83: logo of the NSF company in The Netherlands

The DR 38 A and FR 38 A are small VHF (66 - 75 MHz) transceivers, and are basically the same, other than the power supply. The Draagbare Radio ( = portable radio) 38 A (DR 38 A) was used in mobile stations (radio trucks, cars); it had a 6 Volt battery and two DC-DC "Zerhacker" vibrator/chopper-converters to generate the anode and grid voltages. The FR 38 A was for fixed-base stations; it had a 110-240 VAC transformer-rectifier power supply. The set measured 25x38x22 cm (HxWxD, ≈10x15x8½ inch). Its original function was that of a mobile phone. The transmitter operated on a single frequency, and had an output power of 3 - 5 Watt (A2/A3 modulation). The receiver covered the entire 66 - 75 MHz band. The "38" implies that the design entered into service in 1938. In 1939, the first production series of 200 units was delivered to local authorities in The Netherlands (fire departments, police, ambulance services, and the national Radio Monitoring Service (Radio Controle Dienst, RCD, of the Dutch PTT). The Ministry of Defense (MoD) requisitioned a number of these sets during the months leading up to WW2. The German occupation forces shipped the sets to Germany, where they were also used by the police (Berlin, starting 1940). Ref. 26F. It appears that these transceivers were also built by Philips UK.


Fig. 84: a "Dr 38 A" set installed in a car

(source: ref. 26G)


Fig. 85: an "FR 38 A" with its power supply and transceiver chassis

(source: www.cdvandt.org)


During WW2, the Royal Hungarian Army (RHA) used standard German Feld-Hell machines, probably with Hungarian legends/labels:


Fig. 86: field telephone exchange unit of the Hungarian army, with "Klappenschrank" switch board and German Feld-Hell machines

(source: ref. 27A)

Overall, the RHA used Hellschreibers from 1939 until 1958. The Magyar Államvasutak (MÁV, Hungarian State Railways) also used the Hellschreiber system, but with commercial "Presse Hell" printers.


The Italian Royal Army (Regio Esercito, 1861-1946) also used Feld-Hell machines, with legends in Italian.


Fig. 87: Feld-Hell machine of a mobile Signals unit of the Italian Army, being powered with a car battery

(source: forum of Collezionisti & Radio Operatori Stationi Ex Militari - CROSEM)

For instance, the 1943 document below states that the Engineer Corps of the Nr. II Army Corps had eight Siemens-Hell (Feld-Hell) teleprinters that are used over phone-lines, and that will subsequently be used over existing radio links, without the need for any additional equipment. I do not know with what type of radios the Italian Feld-Hells were used.


Fig. 88: mention of eight Feld-Hell machines of the 2nd Army's Engineer Corps

(source: eBay)


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External links last checked: March 2016

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