- Intro page:
- [FuG 120 overview]
- [Evolution of the "Bernhardine" printer]
- ["Bernhardine" Hellschreiber printer]
- [Printer-channel for signal-strength]
- [Printer-channel for azimuth]
- [Printer model HS 120]
- [Printer model Psch 120]
- [Printer model Psch 120A]
- [Printer model Psch 120k]
- This page:
- [FuG 120 overview]
- [Printer-amplifier SV 120]
- [Filter-unit SG 120]
- [Switching-unit UG 120]
- [Power-supply U 120]
- [Mounting frames]
- [Test equipment]
- [Aircraft equipped with FuG 120]
- [FuBl radio-navigation receiver]
- ["Bernhardine" for FuG 139 "Barbarossa" & FuG 126 "Baldur/Bord"]
- [Unknown/unclear aspects]
By January of 2019 this page had grown to 125 photos and diagrams. It had become rather large (ca. 18 MB download size), which caused long download times for some users. I decided to split the page in two: equipment items remain on this page, general introduction and printers have moved to a separate page. Please continue using the (unchanged) items lists above, and update your bookmarks accordingly.
- ["Bernhard/Bernhardine" Luftwaffe radio-navigation system]
- [FuSAn 724/725 "Bernhard" ground station]
- ["Bernhard" station locations]
©2004-2019 F. Dörenberg, unless stated otherwise. All rights reserved worldwide. No part of this publication may be used without permission from the author.
Latest page update: October-November 2019 (added ref. 248, 249, 256 and associated text, added high-res version of ref. 15).
Previous updates: 1 September 2019 (added patent nr. 754395)
The FuG 120 "Bernhardine" printer system is the airborne counterpart of the FuSAn 724/725 "Bernhard" radio-navigation beacon of the Luftwaffe, 1941-45. It uses the standard on-board EBL3 VHF receiver that was already used with other beacon systems during "blind" approach and landing, and in combination with beam systems for guiding bombers and fighter aircraft to their target. The printer system provided the operator with the bearing from the selected "Bernhard" ground station, and could also receive short "Reportage" text messages with information about enemy aircraft. The official German designation says it all: the FuG 120 is a "UKW-Richtstrahl-Drehfunkfeuer-Empfangszusatz mit Kommandoübertragung". That is, a VHF directional rotating-beam receiver-accessory with command data-link.
Fig. 1: "Bernhardine" airborne Hellschreiber printer of the "Bernhard/Bernhardine" radio-navigation system
(click here for a full size image)
The FuG 120 "Bernhardine" system comprises the following equipment items (ref. 4, 5, 15, 42, 43, 44, 85B/C/D):
- SV 120 printer amplifier unit ("Schreibverstärker"),
- SG 120 audio filter unit ("Siebgerät", "Schreibgabelschaltung"),
- UG 120 switching unit ("Umschaltgerät"),
- SpKf 1a mode switch ("Sprechknopf"), system mode-switch (landing beacon vs. "Bernhard" navigation-beacon); modified PPT-switch ("push to talk")
- U 120 power supply unit ("Umformer"),
- HS120 dual-trace Hellschreiber printer ("Hell-Schreiber") or Psch 120 ("Peilschreiber" = bearing-printer, also a Hellschreiber).
Table-1: manufacturers of the HS 120 (Dr.Ing. Hell company) and Psch 120 (Siemens & Halske LGW)
(source: ref. 44)
According to ref. 44 (p. 188), most of these equipment items date back to 1941, with the exception of SpKf1a (1942), Psch 120 (1942), and SV 120 (1944). However, ref. 3 suggests that series production did not start until 1943, and also states that the first "Bernhard" ground stations were built in 1942.
Fig. 2: Test rack with FuBl 2 navigation receiver system (left) and rack with FuG 120 "Bernhardine"
(source: Fig. 39 in ref. 181, Fig. 6 in ref. 183, p. 99 in ref. 3)
Of course, the aircraft installation included a number of mounting frames and interconnect items (besides cables):
- RDFS 120, "Rahmen für Drehfunkschreiber": mounting frame for rotating-beacon printer,
- UF 120, "Umformerfußplatte": mounting plate for power converter U 120,
- RSV 120, "Rahmen für Schreibverstärker": mounting frame for printer amplifier SV 120,
- SGF 120, "Siebgerät-Fußplatte": mounting plate for filter unit SG 120,
- VD 120, "Verteilerdose": junction box,
- ZLK VIII S 3, "Zwischenleitungskupplung": splitter/coupler unit.
The equipment items UG120, SV120, U120, as well as the installation items RDFS 120, UF120, SGF 120, RSV 120, and VD 120, were all manufactured by a Telefunken plant in Berlin-Zehlendorf (same part of Berlin as the Hell company) or in Erfurt. The associated 3-letter military manufacturer code is "bou". The SG 120 filter unit was manufactured by Siemens Luftfahrtgerätewerk (LGW) Hakenfelde GmbH, manufacturer code "eas". The SpKf1a mode-switch and the ZLK VIII S 3 coupler-unit were made by Frieseke & Höpfner, Spezialwerke für Flugfunktechnik in Berlin Potsdam-Babelsberg and in Breslau. Their manufacturer code was "gqd" (p. 188 in ref. 51).
The total weight of the FuG 120 units (incl. mounting frames) is about 38 kg (84 lbs).
In addition to the on-board equipment, there was a number of ground-test equipment items (ref. 15, 44, 45), mostly built by Telefunken (p. 188 in ref. 44):
- TOG 120, "Tongenerator": an audio signal generator,
- PV 120 and PV 64, "Prüfvoltmeter",
- PschMG 120, "Peilschreibmeßgerät", a tester for the Hellschreiber printer,
- PS 120, "Prüfsender": transmitter / signal generator to test the complete functionality of the FuBL2 plus FuG120. This implies a "Bernhard" beacon simulator,
- PGst 120, Prüfgestell, a test rack (possibly such as shown in Figure 2 above).
PRINTER AMPLIFIER SV 120 (SCHREIBVERSTÄRKER)
The SV 120 ("Schreibverstärker") is the dual-channel printer amplifier unit of the FuG 120. All Hellschreibers require a "tone-detector plus printer-solenoid driver-amplifier" (see Figure 66). It converts received tone-pulses into energization pulses for the electro-magnets of the printer. The audio input signal is amplified, band-pass filtered, rectified. A final amplifier acts as a power-switch.
Fig. 66: Simplified principle diagram of a standard Hellschreiber printer-amplifier channel
However, the SV 120 is much more than just two such channels - see Figure 69. In total, there are 13 tubes (valves): five RV 12 P 2000 pentodes, five LV1 low-noise power pentodes, and three LG6 dual-diodes (full-wave rectifiers).
Fig. 67: SV120 tubes RV12P2000, LV1, and LG6 (to the same scale)
Fig. 68: The SV 120 printer amplifier
(source: Fig. 10 and 11 in ref. 200; note the hinged cover on the three rectifiers, one is flipped down)
Fig. 69: Simplified principle diagram of the SV 120 printer amplifier unit
(source: adapted from Appendix-b in ref. 15)
Let's walk through the above block diagram. The first block is the pre-amplifier with one RV 12 P 2000 pentode tube (valve):
- The input is audio from the EBl 3 receiver.
- The volume control potentiometer is located on the HS 120 printer unit.
- The output of the pre-amp goes to a separate dual-channel audio filter unit, the SG 120.
Fig. 70: Pre-amplifier and filter
In the SV 120, the two audio outputs from the filter unit are passed through separate two-stage amplifiers. Each amplifier comprises an RV 12 P 2000 pentode followed by an LV 1 pentode.
The output of the 2-stage amplifier for the bar-graph printer is transformer-coupled to two other stages:
- One for the 1800 Hz constant tone - for the bar-graph printer.
- One for the 2600 Hz Hellschreiber tone pulses - for the azimuth printer.
The output of the 2-stage amplifier for the bar-graph printer is transformer-coupled to two other stages, see Figure 71:
- An Automatic Gain Control (AGC) stage. Its output goes back to the EBL 3 receiver. Remember that the purpose of this printer channel is to print the strength of the signal from the twin-beam of the Bernhard beacon. This AGC has a short attack time, and a very long decay time. These time constants ensure that the AGC-signal is fairly constant during the entire passage of the beam (3-5 sec), so as not to distort the sharp signal minimum between the two main beam-lobes. It also ensures that side-lobes and rear-lobes of the antenna pattern do not cause the printer motor printer magnets to be enabled. Via the AGC, the side- and rear-lobes actually help prevent the receiver gain from becoming too high. The gain of the AGC-amplifier is high, and a threshold is applied at the input. This AGC makes the performance of "Bernhardine" relatively independent of the distance to the beacon.
- A rectifier/amplifier. Here, the amplitude of the received 1800 Hz tone is first converted to a DC voltage level. Then a sawtooth signal is added, and finally a fixed bias voltage is added. The summed voltages are input to the control grid amplifier tube. This tube acts as a switch, with a small hysteresis. This effectively converts the amplitude of the tone signal to the width ( = duration) of pulses. These pulses are amplified and used to energize the printer-magnet of the bar-graph printer. For a pulse with maximum duration, the printer prints a full-height bar. In absence a pulse (zero width), no bar is printed. The required sawtooth signal is generated by quickly charging a capacitor via a contact that is actuated by a notched wheel on the shaft of the printer-spindle. The capacitor is discharged via a choke coil. The principle schematic of this pulse-width modulator is discussed here.
Fig. 71: Receiver-AGC and bar-graph printer driver
The output of the 2-stage amplifier for the azimuth printer is transformer-coupled to three other stages, see Figure 72:
- An Automatic Gain Control (AGC) stage. Its output goes to the first tube of this 2-stage amplifier. The AGC keeps the signal level of the received 2600 Hz Hellschreiber tone pulses (azimuth data) constant.
- A rectifier/amplifier. Here, the received 2600 Hz tone pulses are rectified. The rectified pulses turn the driver-amplifier on/off, to energize both the printer-magnet of the azimuth printer, and the synchronization magnet-solenoid.
- A second rectifier/amplifier. This detector is used to start and stop the entire HS 120 printer. Via relay contacts, the motor is turned on, the anode voltage of the two printer-solenoid driver tubes is enabled, and the AGC output to the EBL 3 receiver is enabled. The detector has a hang-time of 1.5 sec, to avoid that the relay de-energizes the system too quickly when the audio signal levels go down. The purpose of this, is to only print (and use paper) when the main beams of the beacon are being received. Once the bar-graph and compass rose segment are printed, the paper does not move until the next beam passage, some 30 seconds later. This makes it easier for the crew to read the print-out.
- Ref. patent 767527 proposes "a simple method" for start-stop control of the printer system, without using complicated things such as AGC. This involves a notched disk that is "somehow" closely synchronized to the rotation of the beacon's antenna system. The width of the notch corresponds to that the azimuth segment of interest. It actuates a switch that enables the printer. The position of the switch is adjustable, so as to be able to pre-select the azimuth segment. This patent has two weak points: 1) undefined synchronization method that is simpler than AGC, and 2) to be able to adjust the switch position, the bearing must already be known - which defeats the purpose of this method.
Fig. 72: AGC and printer-magnet drivers for the azimuth printer
According to patent 767354, the field-strength of the received continuous signal could vary as much as 1:10000 (80 dB amplitude ratio) between maximum and the deep null, necessitating a receiver/filter characteristic with compressing/limiting gain curve. The received signal strength obviously depends on the altitude of the aircraft and its distance (range) from the beacon. Patent 767526 foresees an automatic gain control, using yet a third signal transmitted by the ground-station, via an omni-directional antenna system. However, this was never implemented in the Bernhard/Bernhardine system.
As noted in the "Evolution of the "Bernhardine" printer" section, the the SV120 printer amplifier unit and the Printator disk printer were originally (October 1940) to be developed as an improved cockpit instrument that was needed for testing with the "Knickebein" beam system (ref. 204A, 204F). The Telefunken-internal codename for the printer-amplifier was "Ulrich" (ref. 181, p. 83):
Fig. 73: The SV120 originally had the Telefunken code name "Ulrich"
(sources: Fig. 41 & p. 83 in ref. 181, Fig. 4 in 183)
FILTER UNIT SG 120 (SIEBGERÄT)
The "Bernhard" navigation beacon has two AM transmitters. Their carrier frequencies were spaced 10 kHz (±1 kHz). One carrier was modulated with a constant 1800 Hz tone. This creates sidebands at 1800 Hz above and below the carrier frequency. The second carrier was modulated with a 2600 Hz tone. Hence, this carrier also has sidebands: 2600 Hz above and below the carrier frequency. However, the 2600 Hz tone was on-off-keyed with Hellschreiber-pulses. So, each of the 2600 Hz sidebands itself has an infinite Fourier-series of sidebands. As these tone pulses are not a square-wave, the latter sidebands are not individual frequencies (like a comb), but are "smeared" into half sine-wave envelopes. See Figure 74. The tone-pulse transmitter limits the bandwidth of the sidebands to 400 Hz. This is sufficient to pass the 2nd harmonic of the tone pulses (≈350 Hz), and guarantee proper printing.
Fig. 74: Nominal RF spectrum of the "Bernhard" transmitter outputs
(source: frequencies taken from ref. 15, ref. 181)
The FuG120 "Bernhardine" is operated in combination with an EBL3 shortwave AM navigation receiver. The audio output of the EBL3 contains both the constant 1800 Hz tone from the "Bernhard" beacon's twin-lobe beam and the 2600 Hz Hellschreiber tone pulses that represent the azimuth symbology, as well as the 9-11 kHz (10 kHz nominal) difference between the carrier frequencies of the two "Bernhard" transmitters, ref. 15 (p. 10 = pdf p. 11):
Fig. 75: Audio spectrum of the EBl 3 receiver output
To the best of my knowledge, no original "Bernhard" audio recordings exist today. So I have simulated the sound of a transmission. The recording below comprises two beam-passages: once without the information in Hellschreiber-format (i.e., only the constant 1800 Hz tone), and once the constant tone plus the constant stream of 2600 Hz Hellschreiber-pulses. Note: the second simulated beam passage also includes a 10 kHz tone. As explained above and shown in Fig. 75, this is the normal byproduct of demodulating those two simultaneous AM signals.
Simulated sound of two "Bernhard" beam-passages - without & with Hellschreiber tone pulses
The detector-amplifiers of the the two "Bernhardine" Hellschreiber printers respond to all audio signals that have sufficient amplitude - including noise. But the bar-graph printer should only respond to the 1800 Hz tone signal, and the azimuth printer only to the 2600 Hz signal. This means that the two detector-amplifiers must each be preceded by a filter that only passes the tone frequency of interest. The two required bandpass filters are located in the 2-channel SG 120 ("Siebgerät") audio filter unit. This unit has the Luftwaffe Gerät-Nummer 124-977-A (ref. 15). The unit measures 22.5x16.7x9.3 cm (WxHxD, ≈ 9x6.6x3.7 inch) and weighs about 7 kg (≈ 15.5 lbs); ref. 15, 212.
Fig. 76: The SG120 2-channel audio filter unit - cover removed
(source: Fig. 12 in ref. 200; the three large metal-shielded boxes contain the seven inductor coils)
Fig. 77: Block-diagram of the SG120 2-channel audio filter unit
(source: adapted from ref. 15)
Each filter channel comprises a number of series and/or parallel LC-circuits, of which two pairs are stagger-tuned: two parallel-LC circuits in series, or two series-LC circuits in parallel, with slightly different resonance frequencies. The bandpass filter for the Hellschreiber tone pulses has a bandwidth of 400 Hz (ref. 15). Obviously, the center-frequency of the two bandpass filters is the same as the modulation tones of the transmitters: 1800 and 2600 Hz, respectively. Unfortunately, the manual (ref. 15) only list the values of all the capacitors, but not of the seven inductors. So the actual filter characteristics can not be reconstructed (unless an intact SV120 unit is found).
Fig. 78: Audio spectrum of the two SG 120 filter-channel outputs
The two separate tone outputs of the filter unit are returned to the SV120 printer-amplifier unit.
The SG120 was manufactured by Siemens Luftfahrtgerätewerk (LGW) Hakenfelde GmbH (p. 188 in ref. 44). LGW was located in the borough of Berlin-Spandau, just across the Havel river next to Siemensstadt. LGW was a 1940 spin-off of Siemens Apparate und Maschinen GmbH (SAM). Its military manufacturer code was "hdc"; the code "hnu" was used for international (export) products. LGW made a wide variety of aircraft equipment, such as gyros, temperature gauges, radio altimeters, course indicators, switches, connectors, indicator lights, course guidance equipment, and autopilots.
SWITCHING UNIT UG 120 (UMSCHALTGERÄT)
During approach and landing, the EBl 3 beacon receiver works together with the EBl 2 marker-beacon receiver. In this configuration, the EBl 3 receives an automatic gain control (AGC) signal from the EBl 2, and the EBL2 receives the audio frequency (AF) output of the EBl 3. When the EBl 3 is to work with the "Bernhardine" system, the FuG 120 takes the place of the EBl 2. A mode switch controls the UG 120 switching unit. The UG 120 was built by Telefunken (ref. 44, 212). It measures 22.2x20x4 cm (WxDxH, ≈9x8x1.6 inch) and weighs about 0.5 kg (≈1.1 lbs).
This unit is basically a small box with a 4P2T relay (4 sets of changeover contacts):
Fig. 79: Umschaltgerät UG 120 - switch-box
(source: Fig. 16 and 17 in ref. 200)
Fig. 80: Principle diagram of the UG 120 switching unit
(source: adapted from Figure-7 and Appendix-e in ref. 15)
The normal cable that connects the EBl 2 and EBl 3, is replaced with two cables that plug into a splitter/coupler unit: the ZLK VIII S 3 ("Zwischenleitungskupplung"). A third cable connects this coupler to the UG 120 switching unit.
The re-configuration is done with the SpKf 1a mode switch. This is a modified SpKf 1 "Sprechknopf" switch. The latter is used to switch a microphone on and off, like a push-to-talk switch (PTT). SpKf 1 has switch positions that are labeled "EIN" (on) and "AUS" (off). Model 1a is a 3-position switch. A white pushbutton enables changing the switch position. The center position is labeled "NFF" ("Navigationsfunkfeuer" = Navigation Beacon). The left & right position are labeled "LFF" ("Landefunkfeuer" = Landing Beacon). In the "LFF" position, the EBl 3 is connected to the EBl 2. In the "NFF" position, the EBl 3 gets its AGC input signal from the FuG 120, and the FuG 120 gets the AF output from the EBl 3. For an example of the SpKf 1a installed in the cockpit of a Messerschmitt Me-262, see Fig. 107 below.
Fig. 81: The 3-position SpKf1a switch
Fig. 82: The SpKf1a switch - manufactured by Frieseke & Höpfner
(source: ref. 44)
The SpKf 1a mode switch (Ln28986) and ZLKVIII coupler were manufactured by "Frieseke & Höpfner, Spezialwerke für Flugfunktechnik" in Berlin Potsdam-Babelsberg and in Breslau. Their manufacturer code was "gqd" (p. 188 in ref. 51). The switch measures 3.5x3.7x5 cm (WxHxD, ≈1.4x1.5x2 inch inch) and weighs 40 grams (1.4 oz.). This company also made other on-board equipment such as amplifiers of type V3 (of the FuG 125a) and V6, mounting frames VR3, VRP6, RSSF6, automatic DF attachment APZ6 (part of Funkpeilsystem EZ6), loop antenna switches RSS6 & RDS6, electro-mechanical DC-DC converter VZ6, and test equipment such as the PK6 and PGV6. Ref. 212.
Fig. 83: Letterhead of the Frieseke & Höpfner company (1945)
POWER SUPPLY U 120 (UMFORMER)
The U 120 is the central high-voltage DC power supply of the FuG120 system. It primarily supplies the anode and grid-bias voltages for the tubes in the the SV 120 amplifier unit. The unit measures 34.2x22.5x16.4 cm (WxHxD, ≈13x9x6.5 inch) and weighs about 12 kg (≈26.5 lbs); ref. 15, 212.
At the heart of the U 120 is an "Einanker Umformer": a single-rotor motor-generator-alternator (MGA). It generates 300 VDC and 17 VAC. Its 24 VDC motor is powered by the standard 28.5 VDC aircraft electrical system (note: 28.5 VDC is the normal charging voltage for 24 VDC lead-acid batteries, like 13.8 is for 12 VDC lead-acid batteries). All internal connections to and from the MGA are passed through line-filters, to suppress commutator noise. The MGA, model ZA-FGGW 95b 60, was manufactured by the Ziehl-Abegg company of Berlin-Weißensee. This company also made motors for the electric locomotives of the "Bernhard" ground station.
Fig. 84: Principle diagram of the U 120 power supply of the FuG 120
(source: derived from Appendix-d of ref. 15)
The U 120 has five outputs. They all go to the SV 120 amplifier unit. The 300 VDC generator output is used for three of the five outputs:
- 300 VDC is taken directly from the 300 VDC generator, and is not stabilized. It used as anode voltage for the printer driver tubes (final amps) in the SV 120. Upon power-up, this output is kept disabled ("open") with a time-delay relay, until the rectifier tube for the 280 VDC grid bias voltage (derived from the 17 VAC) has warmed up. This is done to avoid damage to the driver tubes, and to avoid the HS 120 Hellschreiber from starting up inadvertently.
- 280 VDC is obtained by passing the 300 VDC through a choke coil and a filter capacitor. It is used as the anode voltage for all other tubes in the SV 120.
- 140 VDC is the grid-bias voltage for the tubes in the SV 120. It is derived from the 280 VDC with a voltage stabilizer tube Metall Stabilovolt type M STV 140/60 Z. The voltage across this stabilizer is 140 Volt at a nominal stabilizing current of 35 mA (65 mA max). This tube is also know as the LK121, where L = "Luftfahrtröhre" (aviation tube) and K stands for "Konstanthalter" = stabilizer, ref. 57. This tube contains two 70 volt gas "glow" discharge stabilizers in series. Likewise, the STV280/40 contains four such stabilizers in series (with individual output pins).
Fig. 85: LG6 tube and Metall Stabilovolt M STV 140/60 Z tube (without extraction knob)
The 17 VAC from the alternator is passed through a transformer. The transformer has four secondaries. Two of the secondaries are up-transformed. Each is full-wave rectified with an LG 6 dual-diode (nominal 400 volt and 100 mA). Here again L = "Luftfahrtröhre", whereas G stands for "Gleichrichter" = rectifier. This tube was originally developed by Philips.
- 280 VDC is obtained by filtering the output of one of the two rectifiers. It is stabilized with two 140 Volt stabilizer tubes in series. This voltage is used as grid bias for the printer driver tubes in the SV 120.
- 140 VDC is obtained by filtering the output of the second rectifier. It is stabilized with a single 140 Volt stabilizer tube. This is used as the bias voltage of the sawtooth signal generator circuit in the SV 120.
The other two secondary voltages are down-transformed, to provide the required 12.6 VAC heater voltage for these two rectifiers.
Fig. 86A: The U 120 power supply - cover removed
(source: Fig. 23 in ref. 200)
Fig. 86B: Equipment label on a U 120 power supply
(source original unedited photo: ©2018 Dufleuve; used with permission)
Fig. 86C: U 120 power supply - top view, cover removed
(source original unedited photo: ©2018 Dufleuve; used with permission)
Fig. 86D: U 120 power supply - front view, cover removed
(source original unedited photo: ©2018 Dufleuve; used with permission)
FuG 120 EQUIPMENT MOUNTING FRAMES
The FuG 120 system comprised the following mounting frames:
- RPsch 120a, "Rahmen für Peilschreiber": mounting frame for a Psch 120(a) bearing printer,
- This is the same as the RDFS 120, "Rahmen für Drehfunkschreiber": lit. mounting frame for rotating-beacon printer,
- UF 120, "Umformerfußplatte": mounting plate for power converter U 120,
- RSV 120, "Rahmen für Schreibverstärker": mounting frame for printer amplifier SV 120,
- SGF 120, "Siebgerät-Fußplatte": mounting plate for filter unit SG 120.
As shown in Fig. 87 below, the HS 120 printer was not mounted on a frame: the four lugs on the back of the HS 120 were mounted directly onto four shock mounts, to mechanically isolate the printer from shocks and vibration.
The FuG 120 "Bernhardine" system includes the following interconnection items (incl. for connections with the FuBl 2 beacon receiver radio system):
- ZLK VIII S 3, "Zwischenleitungskupplung": splitter/coupler unit.
- VD 120, "Verteilerdose": junction box,
- Eight custom cables (including connectors), with the following numbers ("Leitung-Nummer"), ref. 15:
- 371F, 372F (1 conductor),
- 373F, 378F (12 conductors),
- 374F - 376F (8 conductors),
- 377F (2 conductors).
The FuG 120 system test rack includes all of the mounting frames and interconnect items listed above, as well as test rack specific cables ("Prüftafel-Verbindungsleitung", "Hellschreiber-Prüfleitung"):
Fig. 87: Prüfgestell PGst 120 without equipment set, front & back (1944)
(source: combination of Fig. 9 and 11 in ref. 203)
The test rack was made by Telefunken, measures 58x82 cm (WxH, ≈23x32 inch), and weighs about 22 kg (≈49 lbs), ref. 212. Note that through 1943 (ref. 181, 183), the test rack only accommodated an HS 120 printer, but the 1944 rack both an HS 120 and a Psch 120 printer (ref. 203):
Fig. 88: Prüfgestell PGst 120 - FuG 120 system test rack with equipment set
(sources: Fig. 39 in ref. 181 ( = Fig. 6 in ref. 183), Fig. 10 in ref. 203)
The mounting from for the The RPSch 120a (also written as RP.Sch.120A) is the mounting frame for the PSch120(a) "Peilschreiber". The frame measured 16.7x18.6 cm (≈6.6x7.3 inch) and weighed about 320 gram (≈0.7 lbs); ref. 212. It has 4 shock mounts.
Fig. 89: RPsch 120a - mounting frame for the Psch 120(a) printer (same as RDFS 120)
(source: Fig. 4 in ref. 189A)
Fig. 90: Top and bottom of an RPsch 120a
Fig. 91: Label and manufacturer markings on the above RPsch 120a
(source: eBay art. nr. 201963118195)
The metal frame of the RPSch 120a was manufactured for Siemens & Halske AG by the Nürnberger Aluminiumwerke GmbH, tradename Nüral (esp. for engine pistons). This company was founded in 1924. In 1962, it merged with Aluminiumwerke Göttingen GmbH, to form Alcan Aluminiumwerke GmbH. During the 1990s, it was absorbed into US-based Federal-Mogul company. Ref. 213.
Fig. 92: advertising for Nüral die-cast engine blocks and pistons (1940 and 1947)
In the three mounting frame photos below, note that besides two mounting hooks to hang the equipment, each frame as a keying pin ("Sperrstift"). Each pin is placed at a location that is specific to the equipment to be installed on the frame. That equipment has a hole at the corresponding location. This precludes inadvertent installation of different equipment that would otherwise fit on the frame.
Fig. 93: Rahmen RSV 120 - mounting frame for the SV 120 printer amplifier
(source: Fig. 20 in ref. 200)
Fig. 94: Rahmen SGF 120 - mounting frame for the SG 120 filter unit
(source: Fig. 21 in ref. 200)
Fig. 95: Fußplatte UF 120 - mounting frame for the U 120 power supply
(source: Fig. 22 in ref. 200)
Fig. 96: Verteilerdose VD 120 - junction/distribution box
(source: Fig. 18 and 19 in ref. 200)
There also was another junction/distribution box: Verteilerkasten VK 120 a, for the FuG 120 a configuration. Ref. 212, 236.
FuG 120 TEST EQUIPMENT
In addition to the on-board equipment, there was a number of ground-test equipment items (ref. 15, 44, 45), mostly built by Telefunken (p. 188 in ref. 44):
- PS 120, "Prüfsender": transmitter to test the complete functionality of the FuBL2 plus FuG120. This implies a full "Bernhard" beacon simulator.
- PschMG 120, "Peilschreibmeßgerät", for measuring parameters of Hellschreiber printers.
- TOG 120, "Tongenerator": an audio signal generator.
- PV 120 and PV 62, "Prüfvoltmeter": multi-range voltmeters.
The carrying case Prüfgeräte Koffer PK 120 contained the PSchMg 120, TOG 120, PV 120, and PV 62. The case measured ca. 62x45x16 cm (WxHxD, ≈24.6x17.6x6 inch), with an empty weight of ca. 8 kg (≈18 lbs) and 19 kg (≈42 lbs) with equipment. Ref. 212.
The PS 120 "Kurzzeichen Prüfsender" is a complete "Bernhard" beacon simulator: it outputs 30-33.3 MHz radio frequency signals to the EBL3 radio receiver of the on-board FuBL2 radio-navigation system. Hence, it has an antenna connector on the front of the unit (labeled "Antennenbuchse" at the bottom right in Fig. 96). The unit measures 68x51.5x21.9 cm (WxHxD, ≈26.8x20.3x8.6 inch) and weighs about 40 kg (≈88.5 lbs); p. 347 in ref. 212). The unit was made by Telefunken (ref. 44).
Fig. 97: Prüfsender PS 120 - test signal generator
(source: Fig. 3 in ref. 202)
Fig. 98: rear view of the Prüfsender PS 120 - test signal generator - main cover and module-covers removed
(source: Fig. 4 and 5 in ref. 202: note the notched disk installation at the top center)
The next figure shows a printout that was generated with a PS 120. The paper tape is a little over 4 cm wide, so it was printed with an HS 120 printer.
Fig. 99: Print-out generated with a PS 120
(source: Fig. 2 in ref. 202; the tape is a little over 4 cm wide as the pages in ref. 202 are DIN A4 size paper)
The Hellschreiber pixel sequence for the compass symbology was generated with a rotating notched disk - a standard implementation for Hellschreiber senders. Note that the azimuth trace in the print-out above is repeated every 10 degrees. This is why the notched disk, which is clearly visible in Fig. 100 below, only has about 36 notches. They correspond to the vertical line segments of the letter R, the numerals 3 and 4, and the tick marks for 1, 5, and 10 degrees. As the "Bernhard" beacon rotated at 2 rpm, the disk rotated at 2 rpm x 360°/10° = 72 rpm. The diameter of the disk is about 15.5 cm (≈6 inch), based on photogrammetric analysis of Fig. 97 above.
Fig. 100: Close-up of the notched disk module ("Tastgerät" = keying device) of the PS 120
(source: Fig. 5 and 6 in ref. 202)
The PS 120 also had to simulate the 1800 Hz signal of the twin-lobe beam, with its amplitude change during rotation of the "Bernhard" beacon. This could have been done with an appropriately shaped "propeller" in combination with a photocell. However, no such device is visible in the photos. It is not the 12-blade ventilation fan behind the strobe disk: it would have been turning too fast, there is no light bulb + photocell anywhere near it, and the blade shape would have been wrong. Possibly, the envelope of the signal amplitude was simply generated with a slow sine wave, with a large offset:
Fig. 101: Possible method that was used in the PS 120 to generate the twin-lobe signal strength envelope
(adapted from Fig. 2 in ref. 202)
The required clipping need not have been done in the PS 120, as this was already done in the SV 120 printer amplifier. The compass scale segment printed in Fig. 99 spans 50° and would be covered by two sine wave cycles. The beacon rotates at 12°/sec. Hence, the envelope-modulating sine wave frequency would have been (12°/sec) / 50° ≈ 0.25 Hz.
The designator of the PschMg 120 "Peilschreibmeßgerät" suggests that it was used for measuring certain parameters of Psch 120 / Psch 120a printers. I.e., not for actively testing the printers (by injection of test signals). The unit does not include any measurement instruments. Possibly it is primarily an interface box that was used in combination with other test equipment. The test set was made by Telefunken in Berlin-Zehlendorf. This small unit weighed about 5 kg (≈11 lbs) and measured 28.5x25.4x8.8 cm (≈11x10x3.5 inch). Ref. 212 suggests that it could be mounted in the aircraft, on the same RSV 120 rack as the SV 120 amplifier (which has the same WxH dimensions).
Fig. 102: Peilschreibermeßgerät PschMg 120 - bearing printer test set
(source: Fig. 7 and 8 in ref. 203)
The TOG 120 "Kurzzeichen Tongenerator" tone pulse generator probably produced a selectable 1800 Hz or 2600 Hz sine wave with a manually adjustable amplitude. This would have sufficed to test the SV 120 printer amplifier, the SG 120 dual audio filter unit, and the HS 120 or Psch 120(a) printer. The printer would have printed two solid traces (i.e., without white pixels). The unit was made by Telefunken (ref. 44). The unit measured ca. 19x10x11 cm (HxWxD, ≈7.5x4x4 inch) and weighed 2.1 kg (≈4.6 lbs). Ref. 212.
Fig. 103: Tongenerator TOG 120 - tone generator
(source: Fig. 1 and 2 in ref. 203)
The test equipment set included two custom "Prüfvoltmeter" test voltmeters: the simple PV 62, and the multi-range PV 120. The latter has a toggle switch for selecting "with/without printer". The PV's were made by Telefunken (ref. 44).
Fig. 104: Prüfvoltmeter PV 62 - multi range voltmeter
(source: Fig. 5 and 6 in ref. 203)
Fig. 105: Prüfvoltmeter PV 120 - multi range voltmeter
(source: Fig. 3 in ref. 203)
AIRCRAFT (INTENDED TO BE) EQUIPPED WITH FuG 120 "BERNHARDINE"
An estimated 2500 Bernhardine units were installed in various aircraft types (ref. 2, primarily night-fighter versions), such as the Messerschmitt Me262 (one of my all-time favorite aircraft), but not in the Me262 day-time fighter version (ref. 58A). In August of 1944, it was decided to install the FuG120 in all night-fighter aircaft (ref. 249). Installation in the Me 262 "bad-weather" fighter ("Schlechtwetterjäger") was decided in December of 1944; this was configuration "A 1 U 2" of the Me-262 (ref. 59). However, it was cancelled due to lack of availability of the equipment in sufficient numbers (possibly due to Allied bombing of German electronics factories, ref. 60). It was removed from the aircraft equipment list early January of 1945 (see handwritten note in ref. 59). An RAF report on the Me 262 B-2a also describes the FuG 120a as equipment intended for that type (ref. 63). The Me 262 B-1a/U1 with Werk-Nummer 110305 "Rote 8" ("Red 8") of the Luftwaffe's 10./NJG 11 (10th Staffel of Nachtjagdgeschwader 11) is in the collection of the Ditsong National Museum of Military History (formerly known as the South African National Museum of Military History). It was equipped with a FuG 120a system (ref. 237), which was removed by the RAF prior to shipment to South Africa in 1947 (ref. 167).
Apparently, a drawing exists that implies installation of a Psch 120 "Peilschreiber" bearing-printer suspended from the canopy between the pilot and radar operator. While purported to be for the Me 262 B-2, this drawing appears to be of the interim night-fighter Me 262 B-1a/U1. Ref. 61, 62. Several captured Me 262 B-1a/U1 showed some equipment. Fig. 106 below shows a piece of equipment above the FuG 16 ZY (VHF telephony/telegraphy transceiver and transponder), between the pilot and the navigator/radio-operator behind him. Based on the size of the equipment, it could indeed be a Psch 120 paper tape printer. A piece of paper tape seems to leave the lower left corner of the equipment. The installation orientation of the equipment also makes sense: the viewing window of the Psch 120 is in its cover, and the printed tape would move right-to-left - as it should, to read the printed symbology.
Fig. 106: The night-fighter version of the Me-262 - with Psch120 ?
(sources: archives of the San Diego Air & Space Museum (SDASM); original photo 1 & 2: no ©, since US Gov't; Psch120: ref. 198A)
Fig. 107: RgK120a and Spkf1a of the FuG120a - to the right of the rear seat of Me-262 B1, W.Nr. 110305 "Rote 8"
(soure: ref. 168; see ref. 236 for the items' F-numbers)
The SG 120, SV 120, and UG 120 of the "Bernhardine" were mounted on a wooden panel against the fuselage behind the rear-seat radio/radar operator. The EBL 3F receiver, FuG 25a IFF-transponder, ZVG 16 radio-nav unit were installed in the same area. The U 120 power supply was located in the equipment bay above the nosewheel, i.e., between the nose cone and the "Waffenraum" gun bay area (together with the U 17 of the FuG 16 ZY VHF transceiver and U 10/S of the FuG 10 transceiver).
Fig. 108: mounting location of the SV120, SG120, and UG120 on a panel against the aft fuselage of an Me-262
(p. 484 in ref. 168; original un-annotated photo © EN-Archive, used with permission; see ref. 236 for the items' F-numbers)
There is at least one more installation configuration of the FuG 120 equipment in the Me-262:
Fig. 109: Bulkhead panel mounting location of the SV120, SG120, UG120 (and the EBl 3F receiver)
(source: ref. 239)
Other types of aircraft equipped with a FuG 120 were Junkers Ju 88G (ref. 58C, 64), Junkers Ju 388 (ref. 58B, 65), Arado Ar234 "Blitz" (ref. 66, 238), and Dornier Do-335 A-6 "Pfeil" (though the latter never entered into active service). It may also have been installed in the Dornier P.254 (Do 435). FuG 120k appears to also have been intended for the brilliantly advanced flying-wing Gotha GO-P-60 (Gothaer Waggonfabrik, GWF), probably the night figter version P-60C. Per ref. 49 (line item 20), Bernhard/Bernhardine flight tests were done in October of 1943, with a Dornier Do-217 M multi-role bomber. Per ref. 76, flight tests were also done in 1943 with the nightfighter version Do-27 N (based on model M ).
Fig. 110: A captured Dornier Do-335 "Pfeil" - twin-engine with push-pull propeller arrangement
(prototype V10 of the version A-6, a 2-seater / 2-cockpit night fighter - shown without radar antennas in the leading edge of the wings)
Fig. 111: List of intended radio equipment of the Dornier Do-335 night fighter version A-6
(source: ref. 241; to be equipped with FuG 220 "Lichtenstein" radar (later the FuG218 Neptun), and FuG350 Naxos radar detector)
Fig. 112: Arado Ar-234 "Blitz" - the world's first operational jet-powered bomber
The FuG 120a is listed as radio equipment item "Schreibnavigationsanlage (Bernhardine)" for the Arado 234 B P5, and located in an equipment area behind the wing:
Fig. 113: FuG 120a is listed on an equipment card of the Arado model B-234 P-5 (31 January 1945)
(source: ref. 238)
Fig. 114: Junkers Ju-88
Fig. 115: Junkers Ju-88 G1 night fighter
(source: The Hugo Junkers Homepage; accessed 2 August 2019)
Shown below are excerpts from the two flight log books of Konrad Rösner (ref. 166). For 1944, there are five flights in a Ju-88 (incl. the night fighter variant G1) for which the remarks column mentions flight testing of the "Berhardine" system:
Fig. 116A: Excerpts from WW2 flight logs of Luftwaffe radio operator Konrad Rösner
(ref. 166; source: courtesy Walter Waiss (archivist of the "Traditionsgemeinschaft Boelcke e.V."), used with permission)
Fig. 116B: Translated transcript of Fig. 112A
Rösner was stationed at Twente airbase in The Netherlands, close to the Dutch-German border. The airbase is half way between the "Bernhard" beacon Be-8 at Schoorl (Bergen) in The Netherlands (ca. 155 km to the northwest of Twente AB) and Be-13 at Buke in Germany (ca. 155 km to the southeast). It is also ca. 330 km southwest of the "Bernhard" Be-9 at Bredstedt in Germany (ca. 30 km southwest of Flensburg). Note that in the remarks column, "Flensburg test/guidance" refers to the FuG 227 "Flensburg" radar homing device, and not to a fighter control station at the town with that name (there was no such station there).
Starting in 1943, a number of Ju 88 model A-4 were equipped with the FuG 120 "Bernhardine" at the Strausberg airbase, some 35 km northeast of down-town Berlin (ref. 248). Strausberg became a Luftwaffe flight training center (Flieger-Übungs- und Ausbildungsstelle) in 1935. It included a Blindflugschule (training for flight solely by reference to instruments) and a large Navigationsschule where 6-months courses were taught, with a planetarium (ref. 256).
Fig. 117: Junkers Ju-388J night fighter
Towards the very end of WW2, the Messerschmitt company conceived a number of highly advanced fighter and bomber aircraft that never went into production. An example of this, is the Me P 1107/I ultra high speed (transonic) bomber, which was planned to have the FuG 120 "Bernhardine" on board (ref. 240):
Fig. 118: Messerschmitt P 1107/I transonic bomber
(source: ref. 240)
THE FuBl RADIO-NAVIGATION RECEIVER SYSTEM
Standard radio-navigation systems for instrument approaches (so-called "blind landing" = solely by reference to instruments) were the "Funk-Blind-Landeanlage" FuBl 1 and the FuBl 2 (initially written with a roman numerals I and II). Ref. 31, 32, 67, 68, 69, 217. The airborne part of the FuBl 1 system is the EB.3, a militarized version of the Lorenz EB.2 (ref. 31). This system was invented in the early 1930s by Ernst Kramar, Walter Hahnemann, et al (Lorenz Co., e.g., US patent 2,072,267 and 2,217,404) and was successfully commercialized for civil aviation around 1937. The principles of the system are used worldwide to this day (ILS - Instrument Landing System, which even uses the original tone frequencies). The ground station (fixed or mobile) had a 500 W transmitter system, the Ansteuerunsgsender AS 2.
The FuBl 2 was basically an FuBl 1 with an extended frequency range and increased sensitivity, to make it work with the Knickebein, Bernhard, and Hermine systems. The airborne system included both a Lorenz EBl 2 and an EBl 3 receiver.
- The EBl 1 "UKW-Blind-Einflugzeichen-Anlage" is a marker-beacon receiver that covered the 30-31.5 frequency range, plus 33.33 MHz (2 selectable frequencies; range limited to ca. 30 km).
- The EBl 2 "Markierungsfunkfeuerempfänger" is marker-beacon receiver with a fixed frequency of 38 MHz. It indicates passing of fan-marker beacons that are placed at fixed distances from the runway, on the extended runway centerline. The EBl 2 was made by Lorenz, but also manufactured under license by Philips, in its factory in Vienna/Austria (ref. 31).
- The EBl 3 is an AM superhet receiver for VHF landing-guidance beam systems ("UKW-Blindflug-Leitstrahl-Anlage". This receiver was developed by Lorenz AG out of the FuG 16 (ref. 29, 70). It was a replacement for the EBl 1. It provides a lateral guidance signal (left/right deviation) to an AFN indicator (Anzeigegerät für Funk-Navigation" model AFN-1, or the later model AFN-2 and AFN-2A), and to a lateral-axis auto-pilot. In combination with navigation beacons such as the Knickebein system, the EBl 1 had insufficient sensitivity for long range navigation (i.e., to targets in England). The EBl 3 was produced by several manufacturers, including AEG Sachsenwerk in Dresden-Niedersedlitz. It comprised seven tubes of type RV 12 P 2000 (schematic: ref. 71), and had an IF of 6 MHz. This receiver has an unusually large bandwidth: ca. 15 kHz. Note that these days, long-, medium- and short-wave AM radio stations only have 5, 9, or 10 kHz channel spacing, and a baseband bandwidth half that size! Initially, the unit had a light-metal ("Elektron") die-cast construction, built by Mahle. Towards the end of the war, the chassis housing and front face were made of simple sheet metal.
Note that the EBl 3 receiver does not contain audio amplifier stages, see Figure 113. The AM envelope-detector of the EBl 3 is an RV 12 P 2000 tube that is used as rectifier diode. Its output is passed straight to the EBl 2 receiver (and, when used with the FuG 120, via the UG 120 switch box to the SV 120 printer-amplifier). The input of the EBl 2 has the DC-blocking capacitors, an isolation transformer, and amplifier/filter stages for a headset output, to generate the normal AGC-signal for the EBl 3, and signals for the AFN1 or (smaller) AFN2 indicator.
Fig. 119: Block diagram of the EBL3 and EBL2 receiver
(source: adapted from ref. 72)
There are several EBl 3 models (ref. 72):
- EBL 3H, where "H" stands for "Handbedienung" = manual tuning (hand-crank). It covered 30.0 - 33.1 MHz with 32 channels (100 kHz channel spacing). These were allocated to the "Bernhard/Bernhardine" system. Channel-33 and channel-34 were set to 33.02 and 33.33 MHz respectively. The latter two channels were for "blind landing" purposes (ref. 77). Model 3H1 had a manual tuning module that could be replaced with an optional remote-controlled tuning unit.
- EBL 3F, where "F" stands for "Fernbedienung" = remote-control tuning. It had no Channel-34, and Channel-33 was set to 33.33 MHz.
- EBL 3G is basically an EBL 3F with +/-15 kHz fine-tuning.
These receivers where normally used in conjunction with landing guidance systems (instrument landing system for "blind" flying). Other than during approach and landing, these receivers could be used or other purposes. The two tone signals transmitted by the "Bernhard" beacon stations were close enough in frequency that they could be received by a single wideband receiver. The two tones were separated by the SG 120 ("Siebgerät") audio filter unit of the "Bernhardine" system, and amplified and rectified in the SV 120 ("Schreibverstärker") unit before being passed to the printer unit.
Fig. 120: Receiver model "EBl 1"
Fig. 121: Receiver model "EBl 2"
The only aircraft actually equipped with the EBl 3 were (ref. 74, p. 106 in ref. 2): the bomber version of the Ar-234, the nigh-fighter version of the Ju-88 and Do-335 (appendix II in ref. 8), Do-217 (ref. 75, 76), and the bad-weather fighter ("Schlechtwetterjäger") version of the Me-109, the Me-262 (ref. 25a, appendix II in ref. 8), Ju-388 (ref. 58B), FW-190, and Ta-152, and the reconnaissance version of the Me-109, Me-262, Ar-234 (planned only, per ref. 74), and Ta-152. The latter is an early 1945 high-altitude interceptor-fighter derivative of the ubiquitous Focke-Wulf FW-190. The designator "Ta" refers to the renowned FW chief-designer, Kurt Tank. The EBl 3 measures 23x14.3x15.6 cm (WxHxD, ≈9x5.6x6 inch).
Fig. 122: Receiver model "EBl 3H1"
Fig. 123: Receiver model "EBl 3H"
(courtesy Erich Werner, used with permission)
Fig. 124: Receiver model "EBl 3H"
(source: Figure 5.2 in ref. 78)
Fig. 125: "Landeempfänger" EBl 3 (lower equipment row, right of center) in a "Bordfunkanlage" FuG 10 P
(source: Figure 4.4 in ref. 78)
After the war, the small company Curt Höhne Radiomechanik (radio sales & repairs) in Dresden-Radebeul, somehow "acquired" the EBl 3 inventory of the Sachsenwerk factory from the Russian authorities, and converted parts of them to car radios (ref. 79) such as the AS503-OS. Conversions were also published for the 2m (145 MHz) amateur radio band (e.g., ref. 80 from 1952).
Fig. 126: Receiver model "AS503-OS"
(source: ref. 79)
Below is a listing of patents related to Bernhard/Bernhardine.
|Patent number||Patent office||Year||Inventor(s)||Patent owner(s)||Title (original)||Title (translated)|
|767354||RP||1936||-||Telefunken G. für drahtlose Telegraphie m.b.H.||Verfahren zur Richtungsbestimmung||Method for direction-finding [this is the primary "Bernhard" patent]|
|730625||RP||1937||R. Hell||Dr.-Ing. Rudolf Hell||Verfahren zur Registrierung des Verlaufes veränderlicher Stromkurven||Method for printing the trace of varying signals [pulse-width modulator, Hell printer for signal-level track of Bernhardine]|
|767513||RP||1939||A. Lohmann||Telefunken GmbH||Empfangsseitige Schreibvorrichtung zur Durchführung eines Verfahrens zur Richtungsbestimmung [Wachsschreiber]||Receiver-side printer for the implementation of a method for direction-finding [wax printer, infinite loop, erasable tape]|
|767526||RP||1938||A. Lohmann||Telefunken GmbH||Verfahren zur Richtungsbestimmung||Method for direction finding [proposes 3rd beam, for AGC]|
|767527||RP||1938||A. Lohmann||Telefunken GmbH||Einrichtung zur periodischen Ein- bzw. Ausschaltung einer Registriervorrichtung||Device for switching on and off of a printer|
|767536||RP||1940||A. Lohmann||Telefunken GmbH||Empfangsseitige Schreibvorrichtung zur Durchführung eines Verfahrens zur Richtungsbestimmung||Receiver-side printer for the implementation of a method for direction-finding [print medium is erasable Printator foil disk instead of Printator tape]|
|767919||RP||1940||H. Muth||Telefunken GmbH||Verfahren zur Richtungsbestimmung unter Verwendung eines rotierenden Funkfeuers||Method for direction-finding with a rotating beacon [using only twin-lobe beam]|
Here are some ancillary patents:
|Patent number||Patent office||Year||Inventor(s)||Patent owner(s)||Title (original)||Title (translated)|
|562307||RP||1929||J. Robinson||J. Robinson||Funkpeilverfahren||Method for direction finding [transmission of coursepointer, or compass rose info via Nipkow-video]|
|620828||RP||1933||-||Marconi's Wireless Telegraph Co. Ltd.||Funkpeilverfahren||Method for direction finding [transmission of compass rose info via Nipkow-video]|
|754395||RP||1941||Gerhard B.Hagen||Telefunken GmbH||Einrichtung zur Registrierung von langsam veränderlichen Spannungskurven.
Note remarkable "similarities" with the 1937 Hell patent nr. 730625
|Arrangement for printing slowly changing voltage curves|
Patent office abbreviation: RP = Reichspatentamt (Patent Office of the Reich), DP = deutsches Patentamt (German Patent Office)
Patent source: DEPATISnet
- Ref. 2: pp. 76-110, 224 in "Die deutschen Funkführungsverfahren bis 1945", Fritz Trenkle, Alfred Hüthig Verlag, 1987, ISBN 3778516477, 215 pp.
- Ref. 3: pp. 94-102 in "Die deutschen Funk-Navigation und Funk-Führungsverfahren bis 1945", Fritz Trenkle, Motorbuch Verlag, 1995, 208 pp., ISBN-10: 3879436150.
- Ref. 4: p. 260 in "A survey of continuous-wave short-distance navigation and landing aids for aircraft", C. Williams, Journal of the Institution of Electrical Engineers - Part IIIA: Radiocommunication, Volume 94, Issue 11, March-April 1947, pp. 255 - 266.
- Ref. 5: "Instruments of Darkness: The History of Electronic Warfare, 1939-1945", new ed., Alfred Price, Greenhill Books, 2005, 272 pp., ISBN-10: 1853676160; original edition: William Kimber and Co., Ltd, 1967.
- Ref. 5A: pp. 236-237; Same as pp. 274-275 in the excellent German translation: "Herrschaft über die Nacht: Spionen jagen Radar", Alfred Price, publ.: Bertelsmann Sachbuchverlag Reinhard Mohn, 1968, 304 pp., ASIN B0000BT35X.
- Ref. 5B: p. 82 - second of sixteen photo pages.
- Ref. 6: "G.A.F. Night Fighters - Recent Developments in German Night Fighting" [transcript], Air Ministry, Air Ministry, Assistant Director of Intelligence - Prisoner Interrogation, Wing Cmdr. S.D. Felkin, A.D.I. (K) Report No. 125/1945, January 1945, 18 pp.
- Ref. 7: "Beiträge der Firma Siemens zur Flugsicherungstechnik und Luftfahrt-Elektronik in den Jahren 1930 bis 1945 (Teil 1 & 2); H.J. Zetzmann, in "Frequenz - Zeitschrift für Schwingungs- und Schwachstromtechnik"
- Ref. 7A: Part 1: Vol. 9, Nr. 10, 1955, pp. 351-360.
- Ref. 7B: Part 2 (pp. 387, 388, 392): Vol. 9, Nr. 11, 1955, pp. 386-395.
- Ref. 8: "Radio and Radar Equipment in the Luftwaffe - II, Navigational Aids" [transcript], Air Ministry, Assistant Director of Intelligence - Prisoner Interrogation, Wing Cmdr. S.D. Felkin, A.D.I. (K) Report No. 357/1945, 1945, 18 pp. Source: www.cdvandt.org
- Ref. 15: "Beschreibung und Betriebsvorschrift für Funk-Navigationsanlage FuG 120" [Description and Operating Manual for Radio-Navigation System FuG 120 "Bernhardine", with 2-channel Hellschreiber radio-navigation printer], Telefunken G.m.b.H., document FN-T-GB Nr. 1932, December 1944, 43 pp. [File size: 66 MB - a good-but-lower resoluton file is here 26 MB]
- Ref. 21: Drehfunkverfahren", pp. 119-130 in “Bordfunkgeräte - vom Funkensender zum Bordradar“, Fritz Trenkle, Bernard und Graefe Verlag, 1986, 283 pp., ISBN 3-7637-5289-7
- Ref. 26: "Bordfunkgeräte - vom Funkensender zum Bordradar", Fritz Trenkle, Bernard und Graefe Verlag, 1986, 283 pp., ISBN 3-7637-5289-7.
- Ref. 26A: pp. 61-63, "Kommandoübertragungszusätze".
- Ref. 26B: pp. 97-103, "Leitstrahl-Verfahren" (beam methods).
- Ref. 29: "A new field application for ultra-short waves", Ernst Kramar, Proc. of the IRE, Vol.21, Nr. 11, November 1933, pp. 1591-1531.
- Ref. 31: "Das Funk-Blindlandegerät" [Fu Bl I, EBl 1, EBl 2, Fu Bl 2, Werner Thote, pp. 20-25 in "Radiobote" - Heft 9, May-June 2007 (Jg. 2) [pdf]
- Ref. 32: "Beschreibung und Betriebsvorschrift für Funklande-Empfangsanlage Fu Bl 1 Ex", DTA 140, C. Lorenz AG, 1940, 59 pp. Source: www.cockpitinstrumente.de
- Ref. 42: pp. 195-197 in "Confound and destroy: 100 Group and the bomber support campaign", Martin Streetly, 2nd ed., Jane's Publishing Co., 1985, 279 pp.
- Ref. 43: AVIA 6/9218 "Amplifier and filter units for FUG 120", 1945, Royal Aircraft Factory / Royal Aircraft Establishment, Examination of Enemy Aircraft.
- Ref. 44: pp. 28, 29, 188 in "Luftwaffe Flugzeug-Ausrüstungsgeräte, Band FA/01", Peter Aichner (author & publ.), 1997, 670 pp.
- Ref. 45: "Luftwaffe Prüfvorschrift FuG 120 ToG 120 PV 120 PV 62" ("Bernhardine")
- Ref. 46: Bild 17 in "Deutsche Funkmeßtechnik 1944: ein Vortrag von Leo Brandt, gehalten am 8. Februar 1944, zur Einführung der Zentimeter-Technik für das Funkmeßgebiet", Leo Brandt, Vol. 7 of Bücherei der Funkortung, Sonderheft, Verkehrs- und Wirtschafts-Verlag, 1956, 29 pp.
- Ref. 47: "Die Entwicklung des Hell-Schreibers" by the inventor himself: Rudolf Hell; pp. 2-11 in "Gerätentwicklungen aus den Jahren 1929-1939", Hell - Technische Mitteilungen der Firma Dr.-Ing. Rudolf Hell, Nr. 1, Mai 1940 [in German]
- Ref. 48: "Fehlerbestimmung und Störbeseitigung bei der Anlage FuG120 an Hand des Schriftbildes" [troubleshooting and problem fixing of the FuG120 based on print-outs], Telefunken document FN/Lit. 1920.
- Ref. 49: §19-23 in "Some further notes on G.A.F. Pathfinder procedure", A.D.I.(K) Report No. 187/1944, Air Ministry, Assistant Director of Intelligence - Prisoner Interrogation, Wing Cmdr. S.D. Felkin, 25 April 1944, 5 pp. Source: www.cdvandt.org.
- Ref. 50: Cover sheet + pp. 2, 3, 196 of "Gerätliste Druckvorschrift D 97/1", Oberkommando des Heeres, Heereswaffenamt, Berlin, 1 July 1943
- Ref. 51: "Bauaufsichts-Leitung des RLM (BAL) in Rüstungsfirmen. Monatsmeldungen 1941-1942", Bundesarchiv-Militärarchiv, Bestand RL 3, Generalluftzeugmeister, Archivalienverzeichnis, Signatur 4376-2427.
- Ref. 52: "Gruppenübersicht der Flugzeug-Ausrüstungsgeräte und Anforderzeichen", Reichsluftfahrtministerium (RLM).
- Ref. 53: "Dienstanweisung für die Bauaufsichten (BAL) des Reichsluftfahrtministeriums", Teil 1, "Aufgabengebiet", 1 August 1940 (supersedes issue of 1 April 1937), Luftwaffen Dienstvorschrift 61/1 (L. Dv. 61/1), 33 pp.; source: www.cdvandt.org.
- Ref. 54: Sheet 7 in Section 0.1 of A.L. No. 35 of Sub Committee for the Investigation of German Electronic and Scientific Organisation (SIGESO), 9/11/1945, Report Vol. 1, Part I. Source: www.cdvandt.org.
- Ref. 55: "Verlagerungsbetrieb C. Lorenz AG Zweigwerk 14 in Falkenstein/Vogtland, 1943 bis 1946", Werner Thote, Arbeitsgruppe Betriebsgeschichte ROBOTRON Radeberg, November 2012, 12 pp. Retrieved 2 November 2015. [pdf]
- Ref. 57: "Luftfahrtöhre LK1221, Metallstabilisator (M STV 140/60 Z)" [datasheet], RLM Luftfahrtsröhren Ringbuch, April 1943, 2 pp.
- Ref. 58: "The Warplanes of the Third Reich" [by far the most complete reference work on German WWII aircraft], William Green, Gallahad Books, 1970, 672 pp., ISBN: 88365-666-3.
- Ref. 58A: pp. 631-632.
- Ref. 58B: p. 517.
- Ref. 58C: p. 470.
- Ref. 59: Protokoll 8 - 262 Nr. 55, geh.Kdos.ES/V/5506, 7 December 1944, Messerschmitt AG, Augsburg (courtesy R.T. Eger stormbirds.com, used with permission)
- Ref. 60: ca. p. 537 in "Wilde Sau": eine textbegleitende Bildchronik", Vol. 2 of "Jagdgeschwader 300 ", W. Bethke, F. Henning, Struve Druck (publ.), 2001, 568 pp.
- Ref. 61: Nachtjäger 8-262 B 2, Zeichnung Nr. S8-0084, DLH, 7.2.45, NA(PRO) MR 1-820 (1).
- Ref. 62: "Pioniere des Jet-Zeitalters - die historisch-technische Geschichte der ersten Strahlflugzeuge", Heinz. J. Nowarra, Der Landser Grossband, Band 362, Pabel Rastatt Verlag, 1964, 74 pp.
- Ref. 63: A.I.2.(g) Report No. 2370, dated 23rd August, 1945.
- Ref. 64: p. 15 in "The Junkers Ju 88 Night Fighters - Profile Number 148", Alfred Price, Profile Publications Ltd., 1967, 15 pp.
- Ref. 65: p. 79 in "Ju 188 Ju 388 cz. 2", Monografie Lotnicze Nr. 34, Robert Michulec, AJ-Press, 1997, 82 pp.; the full document (in Polish) is here [file size 49 MB] See note 1
- Ref. 66: pp. 13, 18 in "Blitz!: Germany's Arado Ar 234 Jet Bomber", J.R. Smith, E.J. Creek, Merriam Press, 1997.
- Ref. 67: "He 111 H-6, Flugzeug-Handbuch (Stand August 1942), Teil 9D, Bordfunkanlage mit: FuG X, PeilG V, FuBl I bzw. FuBl 2 und FuG 25", D.(Luft) T.2111 H-6 Teil 9D, Ausgabe September 1942, 65 pp.
- Ref. 68: pp. 97-103 of "Leitstrahl-Verfahren", in “Bordfunkgeräte - vom Funkensender zum Bordradar“, Fritz Trenkle, Bernard und Graefe Publ., 1986, 283 pp., ISBN 3-7637-5289-7.
- Ref. 69: "Übersicht über die Funkgeräte der Luftwaffe", Fub-2, Heft 2 of "Arbeitsunterlagen für den nachrichtentechnischen Unterricht", 1. Auflage, Luftnachrichtenschule, Gr. NTU, Halle (Saale), November 1942, 6 pp. [Übersichtstafel Bordfunk- und Bord-Peilgeräte, Bodenpeilanlagen, Bodensender, Bodenempfänger; Overview tables of airborne radios and direction-finders, ground-based direct-finders, transmitters, receivers]
- Ref. 70: "Die Bordfunkgeräte FuG 16 und FuG 17", pp. 28-49 in "Berühmte Bordfunkgeräte - ein Beitrag zur Geschichte der Elektrotechnik" [FuG 10, FuG 16, FuG 17, FuG 25a, FuG 101a, ...], H. Sarkowski, Expert Verlag, 1983, 80 pp.
- Ref. 71: E Bl 3-H schematic, courtesy Erich Werner, used with permission.
- Ref. 72: "Funk-Landegerät Fu Bl 2 Geräte-handbuch" [EBL 2, EBl 3], D.(Luft)T.4058, February 1943, 120 pp. Source: www.cdvandt.org.
- Ref. 73: para.11 and 14 in "G.A.F. night fighters. Recent developments in German night fighting", A. D. I. (K) Report No. 125/45, Air Ministry, Assistant Director of Intelligence - Prisoner Interrogation, Wing Cmdr. S.D. Felkin, 27th January 1945. Source: www.cdvandt.org.
- Ref. 74: "Blind landing and airborne communications equipment. Radio and Radar Equipment in the Luftwaffe - II", S.D. Felkin, Air Ministry Directorate of Intelligence, London/UK, A.D.I. (K) report no. 343/1945, July 1945, 6 pp.
- Ref. 75: Werkschrift "Do 217 N-1, N-2 Fleugzeughandbuch, Teil 9D, Bordfunkanlage (stand Oktober 1943)", Ausgabe Dezember 1943, Dornier-Werke G.m.b.H., 94 pp.
- Ref. 76: page in "Do217-317-417 An Operational Record", Manfred Griehl, Smithsonian, 1992, 237 pp.
- Ref. 77: pp. 291 and 350 in "Geschichte der deutschen Nachtjagd: 1917-1945", Gebhard Aders, 1977, 391 pp., Motorbuch Verlag, ISBN-10: 387943509X. Also appeared as translation with revisions: "History of the German night fighter force, 1917-1945", Jane's Information Group, 1979, ISBN 0867205814, 360 pp.
- Ref. 78: "Die Funklandeanlagen", pp. 45-49 in "Die deutschen Funk-Navigation und Funk-Führungsverfahren bis 1945", Fritz Trenkle, Motorbuch Verlag, 1995, 208 pp., ISBN-10: 3879436150.
- Ref. 79: "Blindlandeempf. EBl 3H", courtesy Erich Werner, used with permission.
- Ref. 80: "Der EBl 3 im UKW-Empfänger" [amateur radio conversion to 2 m band], C. Möller, pp. 556-558 in "Funk-Technik - Fachzeitschr. für Kommunikationselektroniker und Radio- u. Fernsehtechniker; offizielles Mitteilungsblatt. der Bundesfachgruppe Radio- und Fernsehtechnik", Vol. 7, Nr. 20, October 1952
- Ref. 81: RL 39 "Forschungsinstitute der Luftwaffe", test report nr. 275,12-Feb-1945, p. 320-323 in "Das Bundesarchiv und seine Bestände", Boldt, 1977, 940 pp.
- Ref. 82: p. 10 in "Evaluation report, Issues 2-112", Combined Intelligence Objectives Sub-Committee (CIOS)
- Ref. 83: "Kriegstagebuch (KTB) - Chef der Technischen Luftrüstung (TLR), Berichtraum 8.1. - 14.1 1945" [war diary]. Source: www.cdvandt.org.
- Ref. 84: "Funk-Landegerät Fu Bl 2 Geräte-Handbuch", Druckschrift D. (Luft) T. 4058, February 1943,120 pp; source: www.cdvandt.org.
- Ref. 166: pp. 21, 22, 23, 25 in "Flight logbooks of Konrad Rösner, Part 1 (29-Oktober-1940 - 3-May-1944) and Part 2 (3-May-1944 - 9-April-1945)", courtesy Walter Waiss (archivist of the Traditionsgemeinschaft Boelcke e.V.), used with permission.
- Ref. 167: personal correspondence with the Ditsong National Museum of Military History, February 2011. [pdf]
- Ref. 168: "Me 262", Vol. 3, J. Richard Smith, Eddie J. Creek, Classic Publications, 2007, ISBN-13: 978-1903223000, 224 pp.
- Ref. 169: photo of item in collection of the UK Imperial War Museums with Crown Copyright, used in accordance with the Open Government License [pdf]
- Ref. 170: connector specification sheet "Fl 32 113-6 - Elektrische Geräte 20-pol. Steckverbindung Gerades Anbeugehäuse für 20-pol. Kontakteinsätze", RLM, update of Sept. 1944, 1 p.
- Ref. 171: pp. 50-53 in "Vom hydraulischen Regler zum Prozessleitsystem: Die Erfolgsgeschichte der Askania-Werke Berlin und der Geräte- und Reglerwerke Teltow. 140 Jahre Industriegeschichte, Tradition und Zukunft", Lothar Starke, BWV Berliner Wissenschafts-Verlag, 2010, 272 pp.
- Ref. 173: copy of items in file AIR 14/3577 "Signals investigation on 27 to 35 Mc/s "Windjammer" (1943/1944)". Items are in the collection of The National Archives; material with UK Crown Copyright, used in accordance with the Open Government License [pdf].
- Summary of the contents of ref. 173A-173E.
- Ref. 173A: "'Windjammer" observation", by R.A. Fareday (Noise Investigation Bureau [Electronic Intelligence], N.I.B., London), dated 20th June 1944, 1 page.
- Ref. 173B: "Possible "Windjammer" transmissions", report by Flight Lieutenant Douglas of 192 Sq., dated 16th December 1943, 1 page.
- Ref. 173C: "192 Squadron Flight report No. 215/43" by F/Lt Robinson to Squadron Leader Burtler, dated 15th November 1943 (actual report by P/O G.F. Evans of 13th November 1943), 6 pages.
- Ref. 173D: "Windjammer – Arcachon", letter from Air Ministry A.I.4. [intelligence branch section supervising RAF Y Service] to Commanding Officer of 192 Squadron, dated 16th July 1943, 1 page + 1 aerial photo.
- Ref. 173E: "The Windjammer and Dreh-Elektra", by 192 Squadron Leader J. Whitehead, dated 18th June 1943, 1 page.
- Ref. 175: pp. 512-516, 524 in "Activities at Knockholt", J.A. Reeds, Appendix B in "Breaking Teleprinter Ciphers at Bletchley Park - General Report on Tunny with Emphasis on Statistical Methods (1945)", 1st ed., I.J. Good, D. Michie, G. Timms (J.A. Reeds, W. Diffie, J.V. Fields, eds.), John Wiley & Sons, IEEE Press, 2015, 735 pp.
- Ref. 181: "Drehfunkfeuer System Telefunken - Teil 1: Verfahrensbeschreibung EC1-4262" [Telefunken rotating radio beacon, part 1: description of the method], Adalbert Lohmann, Berlin, October 1942, 129 pp., copy nr. 29, personal copy of Albrecht Leyn [note: this document was never printed, other than a very limited number of personal copies, individually approved by Dept. LC-4 (Technisches Amt) of the RLM; ref. 183]; source: corporate archives of DTM Berlin, part of file nr. I.2.060C-06172 [file size: 62 MB]
- Ref. 183: "Das Drehfunkfeuer-Verfahren Bernhard und Bernhardine, System Telefunken" ("Verfahrensbeschreibung Bernhard, Bernhardine", description of the Bernhard-Bernhardine method), Adalbert Lohmann, Telefunken Gesellschaft für drahtlose Telegraphie m.b.H., Berlin-Zehlendorf, Telefunken document EC 1 4310, July 1943, 28 pp., copy nr. 11; source: corporate archives of DTM Berlin, file nr. I.2.060C-04403
- Ref. 194: "Vorläufige Beschreibung und Bedienungsanleitung für Prüfsender "PS 120" für die Funknavigationsanlage "FuG 120" - Fotos des Prüfsenders"; Telefunken Gesellschaft für drahtlose Telegrafie, July 1944, 2 pp.; source: corporate archives of DTM Berlin, part of file nr. I.2.060C-07761
- Ref. 198: FuG 120a and Psch 120a; source: corporate archives of DTM Berlin, file nr. I.2.060C-07754
- Ref. 198A: "Ergänzung zur Beschreibung FuG 120 - Nachtrag: FuG 120a, Peilschreiber Psch 120a", Telefunken Abt. FN/TL, August 1944, 11 pp.
- Ref. 198B: "Funknavigationsanlage FuG 120 a - Einzeladerverlegung" [wiring list & diagram], Telefunken Gesell. für drahtlose Telegraphie m.b.H., document nr. V/F 2297, December 1944, 2 pp.
- Ref. 198C: "Reglerkasten Rgk 120a" [control box], Telefunken Gesell. für drahtlose Telegraphie m.b.H., document nr. V/F 2298, December 1944, 2 pp.
- Ref. 198D: "Peilschreiber Psch 120a Stromlaufplan" [schematic], Telefunken Gesell. für drahtlose Telegraphie m.b.H., document nr. V/F 2334, December 1944, 3 pp.
- Ref. 199: "F-Geräte Peilschreiber Psch 120a", RLM, Ln 28997, outline drawing of the Peilschreiber Psch 120a, no date marked on document, 1 p., source: corporate archives of DTM Berlin, part of file nr. I.2.060C-07759.
- Ref. 200: pp. 16-20 of "Beschreibung und Betriebsvorschrift für Funk-Navigationsanlage FuG 120", Telefunken Gesell. für drahtlose Telegraphie m.b.H., December 1944, 37 pp.; source: corporate archives of DTM Berlin, file nr. I.2.060C-00666
- Ref. 201: 3 photo pages from "Unterlagenmappe und Bedienungsvorschrift zu den Bordnavigationsgeräten "FuG 120" und FuG 120a"", Telefunken Gesell. für drahtlose Telegraphie m.b.H., TFK FN/TL Bord, August 1944; source: corporate archives of DTM Berlin, file nr. I.2.060C-07760
- Ref. 202: 3 photo pages from "Vorläufige Beschreibung und Bedienungsanleitung für Prüfsender "PS 120" für die Funk-Navigationsanlage "FuG 120"", Telefunken Gesell. für drahtlose Telegraphie m.b.H., July 1944; source: corporate archives of DTM Berlin, part of file nr. I.2.060C-07761
- Ref. 203: 5 photo pages from "Prüfgeräte und Prüfung der Anlagen FuG 120 und FuG 120a mit Tongenerator TOG 120, Prüfvoltmeter PV 120, Prüfvoltmeter PV 62, Peilschreibermeßgerät PschMg 120, Prüfgestell PGst 120", Telefunken Gesell. für drahtlose Telegraphie m.b.H., July 1944; source: corporate archives of DTM Berlin, part of file nr. I.2.060C-00643.
- Ref. 204: DFS 120 Drehfunkschreiber [rotating beacon printer], Printator-printer [erasable multi-layer foil printer]; source: corporate archives of DTM Berlin, file nr. I.2.060C-02427
- Summary (in English) of the contents of ref. 204A-204Q, Frank Dörenberg, version 3-Nov-2017, 7 pp.
- Ref. 204A: "Schreibanzeige-Gerät für Flugzeugbordanlage "Ulrich"" [airborne printer-indicator]; letter from Mr Runge and Mr Lohmann of Telefunken Ges.f.drahtl.Telegraphie m.b.H. to Dr Zimmermann of Siemens & Halske A.G., Wernerwerk X, Dept. T-Sondertelegrafen [special telegraphy equipment], 8 October 1940, 1 page. Also see ref. 204F ("Printator" disk printer)
- Ref. 204B: "NF-Weiche für Anlage "Bernhardine"" [audio filter]; internal memo from Mr Schmeisser to Dr. Hartmann, Telefunken Ges.f.drahtl.Telegraphie m.b.H., 9 May 1941, 1 page.
- Ref. 204C: "Patentanmeldung II 153 264 VIIId/21e, 11; vom 8.10.1937" [patent application]; letter from Mr Lohmann of Telefunken Ges.f.drahtl.Telegraphie m.b.H. to Dr. Rudolf Hell in Berlin-Dahlem, 17 May 1941, 2 pages.
- Ref. 204D: ""Bernhardine"-Großserie, Einschaltung der Firmen Dr. Hell und S. & H." [series production]; internal memo to Dr Rottgardt and Mr Lohmann from Mr Tätz, Dept V [“Verkauf”, sales], Telefunken Ges.f.drahtl.Telegraphie m.b.H., 28 May 1941, 1 page.
- Ref. 204E: "Anzeigegerät für "Bernhardine"" [indicator]; internal memo from Mr Lohmann to Mr Tätz, Telefunken Ges.f.drahtl.Telegraphie m.b.H. (TFK), 10 June 1941, 4 pages [ = response to ref. 204D].
- Ref. 204F: "Chronik des Printator-Schreib-Anzeigegerät für Drehfunkfeuer" [1937-1941 chronicle]; internal memo from Mr Lohmann of Telefunken Ges.f.drahtl.Telegraphie m.b.H., 10 July 1941, 2 pages. Also see ref. 204A.
- Ref. 204G: "Dr. Rudolf Hell", letter from Dr Johannesson et al of Telefunken Ges.f.drahtl.Telegraphie m.b.H. to the patent dept. of Siemens & Halske A.G. (S&H), 11 June 1941, 1 page.
- Ref. 204H: "Fertigung der Vierspurenschreiber für Bernhardine" and "Printator-Schreiber und NF-Weiche für Bernhardine, entwickelt bei Siemens & Halske" [4-channel Hell-printer, Printator-printer, and audio filter], internal memo from Dr Johannesson of Telefunken Ges.f.drahtl.Telegraphie m.b.H. (TFK), 11 June 1941, 1 page.
- Ref. 204J: "Drehfunkschreiber DFS 120 nach dem Printatorprinzip für die Anlage "Bernhardine"" [chronicle], internal memo of Mr Schmeisser to Dr Schumacher, Telefunken Ges.f.drahtl.Telegraphie m.b.H., dept FN/TV-Bord in Berlin-Zehlendorf, 12 October 1942, 1 page.
- Ref. 204K: no title, internal memo of Mr Hartmann of Telefunken Ges.f.drahtl.Telegraphie m.b.H., 8 December 1942, 1 page.
- Ref. 204L: "Peilschreiber DFS 120 nach dem Printator-Prinzip für die Telefunken-Anlage "Bernhardine"", letter from Mr Lohmann and Mr Hartmann (in lieu of Mr Görlitz) of Telefunken Ges.f.drahtl.Telegraphie m.b.H., to Mr Pelkmann of Siemens & Halske A.G. (S&H), Wernerwerk Z, in Berlin-Siemensstadt , 12 December 1942, 1 page.
- Ref. 204M: "Peilschreiber DFS 120 nach dem Printator-Prinzip für die Telefunken-Anlage "Bernhardine"", letter from Mr Zimmermann and Mr Pelkmann of Siemens & Halske A.G., Wernerwerk Z, in Berlin-Siemensstadt, to Dr Schumacher of Telefunken Ges.f.drahtl.Telegraphie m.b.H. in Berlin-Zehlendorf, 9 January 1943, 2 pages.
- Ref. 204N: "Chronik des Printator-Schreib-Anzeigegerät für Drehfunkfeuer" [1936-1941 chronicle], internal memo from Mr Lohmann, Telefunken Ges.f.drahtl.Telegraphie m.b.H., 9 February 1943, 2 pages.
- Ref. 204P: "Peilschreiber DFS 120 nach dem Printator-Prinzip", internal memo / position paper from Mr Lohmann (Dept. EC 1) to Mr. Görlitz (Dept. Z), Telefunken Ges.f.drahtl.Telegraphie m.b.H., Berlin, 9 February 1943, 3 pages.
- Ref. 204Q: "Peilschreiber DFS 120 nach dem Printator-Prinzip", internal memo to Mr. Hartmann, Telefunken Ges.f.drahtl.Telegraphie m.b.H., 2 September 1943, 1 page.
- Ref. 204R: "1935 - 1941 "Bernhardine" printer development timeline", summary based on ref. 204A/B/E/F/J/K/L/N/P, Frank Dörenberg, 31 October 2017, 2 pp.
- Ref. 212: pdf pp. 17, 18, 330-350, 388-392 in "Fluzeug-Ausrüstungsgeräte - Teil 9, Mappe 637", RLM, Jan/Sept 1944; source: www.DeutscheLuftwaffe.de [file size 41 MB]
- Ref. 213: p. 168 in "Geschichte Nürnbergs", Martin Schieber (ed.), C.H. Beck publ., 2007, 191 pp.
- Ref. 217: "Empfängersatz der Funklandeanlage FuBl 2", pp. 18-22 and 80-85 in "Exerzierordnung für Flugzeugfunkwarte FuG 10, PeilG 6 mit APZ 6 und FuBl", Fugb-25, Funkgerätelehre, Heft 25, Entwurf zu LDv 702/1, Heft 304c, Luftnachrichtenschuke Halle (Saale), September 1943.
- Ref. 236: "Funknavigationsanlage FuG 120 a - Einbausatz FuG 120 a", Blatt 5 of "Bordfunkanlage Me 262 (Nachtjäger)", Messerschmitt A.G., Augsburg/Germany. Date unknown.
- Ref. 237: pp. 335, 336 in "The Encyclopedia of Weapons of World War II", Chris Bishop (gen. editor), Aerospace Publishing, 1998, ISBN-10: 0760710228.
- Ref. 238: "Ar-234 «Blitz»", Война в воздухе ["Voyna v vozdukhe", "War in the Air" periodical], Issue 133, 2005, S.V. Ivanov (ed.), 108 pp. Retrieved 1 August 2019. [pdf]
- Ref. 239: "Messerschmitt Me 262 A Schwalbe", Robert Pęczkowski, 2nd ed., ISBN 978-83-63678-17-3, 2014, 112 pp.
- Ref. 240: p. 85 in "Luftwaffe Secret Projects - Strategic Bombers 1935-1945", Dieter Herwig, Heinz Rode, Midland Publ., 2000, ISBN 1857800923, 144 pp.
- Ref. 241: p. 9 in "Baubeschreibung Nr. 1600 - Dornier - Nachtjäger Do 335 A-6", Dornier-Werke G.m.b.H., 20 November 1944, 15 pp. Retrieved 3 August 2019. [pdf]
- Ref. 247: "The I.T.T., Siemens and Robert Bosch Organizations", Combined Intelligence Objectives Sub-committee (CIOS), Item No. 1, 7 & 9 (Radar, Signal Communications, Physical & Optial Instruments and Devices), File No. XXXI-38. Source: cdvandt.org. Retrieved 22 September 2019. [pdf]
- Ref. 248: p. 117 in "Aus der Geschichte des Strausberger Fliegerhorstes von 1936 bis 1945", Helmut Bukowski , pp. 107-119 in "Deutsches Soldatenjahrbuch 2003/2004", Vol 51-52 (2003/2004).
- Ref. 249: "Funkausrüstung der Flugzeugbaumuster" [radio equipage of aircraft types], memo to Gen.Nafü/Ln.Insp., dated 16 August 1944, signed by Capt. Franz, 3 pp.
- Instructions regarding equipage of all night fighter planes ("Nachtjäger") with FuG 120 "Bernhardine", and of fighter planes ("Jäger"), combat planes ("Kampfflugzeuge" Ju 88, Ju 388, Do 335, Me 262, Ar 234, He 177, Ju 287), destroyers ("Zerstörer", Do 335), long-range reconnaissance planes ("Fern-Erkunder", Ju 388, Me 264), and trainers ("Schulflugzeuge", Ar 96, Si 204) with other radio equipment (FuG 125 Y, FuG 16 Z, FuG 16 ZY, K 3, FuG 17 Z).
- Ref. 256: "Fliegerhorst Strausberg", Reinhard Tenhumberg. Accessed 27 November 2019. [pdf]
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External links last checked: August 2019, unless stated otherwise.