GEE navigation.

GEE was a Brittish wartime hyperbolic navigation system, used in bomber airplanes of Bomberc Command and airplanes of Coastal Command, like Lancaster, Halifax and Wellington. It was used to maintain the position of the airplane on their way to their targets, often Germany.

An short explainanation of GEE mapping:

By measuring the amount of calibrated pips on the indicator screen, between the  measured beacon pulses from different, fixed GEE transmitters along the country  (so each Gee transmitter gives a high pip on the screen) , and putting these  measurement amounts , called GEE units, in a GEE  map, man could determine the position of the airplane on the map itselves.Each measured GEE  unit has its own hyperbolic curve on that map. In principle, you have to measure 2 Gee units only. The crossing of each curve was the position of the airplane. For more accurency you used more Gee units, so more hyperbolic curves on the map. You have to interpolate the position by these different crossings.

On the internet this system is explaned very often and well.


In the mid, a view of my GEE installation.

Left the GEE receiver with frontend. The receiver is a type R 3645. It is a kind of MF receiver with videoamp. stage. The videostage signal  is fed to the indicator. This receiver picks up the beacon signals which are located on fixed places all in the brittisch countryside.

The frontend is a type 27 b. It converts a tuneable high frequency range of about 65 Mc till 85 Mc into a lower MF frequency of about 6,6 Mc.You could use differnt frontend for different frequency ranges.

In the mid the indicator type 266. On the CRT screen can be seen the beacon-, strobe marker- and calibration pulses.

On the right side the powersupply units, type” voltage control unit no 6″ with its “chokebox no 1”.

These units stabilise a 80 volts 1500 Hz voltage, coming from an alternator.


Here the original alternator, when I received it from an seller  in the UK, type UKX generator.

Normally it is mechanically driven by one of the airplane engines. It delivers the 24 volts DC and 80 volts 1500Hz. Because of the type it was possible to make it run in connecting the 24 volts parts to a 24 volt battery . All it takes about 30 ampere to let it run! In the left box on the generator (right box is 24 volts part with field connection) you could maintain 80 volts 1500 Hz.

The transformers in the receiver- and indicator powersupplies need a voltage of 80 volts 1500 HZ. The demensions of the transformer get smaller and the weight is less then when you use that frequency. Also other electrical equipment do so. Weight is one of the important fact in an airplane.


This is my alternator, type UKX. The little switch on the right is switching on a relay in the no 6 unit, which put the 80 volts on the receiver and indicator. The big switch is putting the 24 volt on the alternator.

These units stabilise the 80 volts from the alternator. Stabilising is needed because of the engine speed is often varying in some circomstances, so the voltage of 80 volts.

In front of it a “ground-flight” switch for switching the whole aircraft installation on the 24 volt from either outside the airplane or airplane batteries themselves. Now used to put the 24 volts on the UKX generator.


Here the receiver and indicator. On the receiver another frontend unit.


This is the screen of the indicator. You could see here the calibration pips and the negative strobe marker pulses. The measured pulses of the beacon transmitters, called A, B and C pulses are not to be seen. This ofcourse because the GEE systen does not exist any more. The last GEE transmitters went down in the end of the year 1960.

The strobe marker puls could be placed on different places along the X-axes by the red and white knobs  at the under side of the front.. By  Putting down the clearingswitch (you can see then the received beacon pules) you first bring the strobemarker puls just under the measured Gee beacon signals, the clearing switch up, you get the caibration pulses, after that you can measure the distance in calibrating pulses between the beginning of the scales and the strobe markerpulses. These differences are called the Gee units. So the position of the strobe marker at that moment is the position of the beacon signal, e.g. A, B or  C  beaconpuls.

I will once build my self a simulator for it, a schematic is already there etc.The it is possible to give a complete demonstration of the GEE navigation system.


With the clearingswitch on the indicator, you get the noise  and the GEE beacon signal of the receiver on your screen of the indicator. With the red gainknob on the indicator on maximum, there will be a level of 2 cm on the screen.


Here, the noiselevel is somewhat lower by less gain on the indicator. The red gainknob is regulating the sensitivity of the receiver. When you are receiving the GEE master and slave signals, you can see also the the pulses of about 1 uS on the screen. But because the GEE system does not exist anymore, the pulses are absent.


Here the front of the GEE receiver, type R 3645. The switch “Z and N ” has an anti jamming function. Often the GEE signals were jammed, in the “Z” position a kind of CW jamming was suppressed then. When no jamming was there, the position of “N” was held. (Normal).

Nice is the lightened scale of the receiver tuning, which indicates also the powersupply is working.


The above side of the GEE 266. Tubes inside are the red VR91.


The side vieuw of the GEE 266.


The other side vieuw of the 266. Right above the EHT tube of the CRT. The compartment on the left under the crystals. On the below centre the MF coils strip of the receiver part.


Above the test set no 210.

This typical test set is used for testing and alighning the GEE installation. It consist of a HF generator, suitable for all the frequencybands of the RF units used in the GEE receiver. All frequency signals unmodulated.

Also a wideband noisegenerator for testing the receiver.

And most import a PRF generator. With this it is possible to generate 15 khz pips on the screen of the GEE indicator. In the test set, there is a generator, which is modulated (switched on and off) by a crystalcontrolled modulator/oscillator. This generator, with it’s frequency tuned on the receiverfrequency of the GEE receiver, is crystalcontrolled by 6 xtals. Frequency A till F. The frequency of the crystals are the same as in the timebase generator of the indicator, in this case the type 266.

By finetuning the PRF (the knob just left of the pilotlamp) on the testset, it is possible to synchronise with the timebase in the GEE indicator. When synchronised, the pips stand still on the screen.

The output of the testset is connected to the GEE receiver input by a coaxialcable.

Also a whip earial can be used, it consist of 3 parts.

The frequency of the generator can be tuned , by a tablechart, by the big black knob at the left on the front.


Here the 15 khz pips on the the screen of the GEE inicator, type 266. The clearingswitch on the indicator is up, position “receiving GEE signals”. The switch on the test at “modulation on”.

By adjusting the gain on the indicator, the noise level can be taken away, so that only the pips and the strobepulses are left.

The faulty part of the of the timebase at the left is probably a fault in the flyback phase or liniarity of the timebase of the circuit. I left it like that. For demonstration purposes it’s not so important.

R 1224

RAF  R1224 A


This is the RAF R 1224 A receiver. It is a superhet receiver. It is part of the Station W/T portable Type 9.

Frequency range was 1,5 Mc – & Mc.

Output impedance 2000 and 8000 ohm.

Heater voltage 2 volt.


R 1147 A receiver

RAF  spitfire receiver R1147A

The R 1147 receiver is a homing receiver for use in a Spitfire aircraft, spitfires of the RAF P.R.U. squadron. P.R.U. stands for Photographic Reconnaisance Units. At that time these Spitfires had no radio of any kind. The receiver was remote controlled by a mechanical bowdencable (splineshaft) from the cockpit. A Mark 5B stopwatch was included in the system package for timing the beacon signals.

This receiver only existed for a short amount of time, starting March 1941. They were loaned from the Royal Navy for a test in that year, because the PRU squadrons needed the use of homing at that moment. Because of the receiver’s weaknesses, they were eventually replaced by the TR 1133 in 1942. The TR 1133 also had communication possibilities.

Frequency range of the R 1147 is 180 Mc-220 Mc. and used a small whip antenna on the aircraft.






The picture above displays the cockpit’s remote control R1147 receiver. It was placed beside the pilot and connected through a splineshaft cable to the R1147. This remote control unit looks just like the one placed on the front of the receiver. Watch the tuning scale on the side of the remote control unit. Markers at A, B, C and D

R 1116A pre war aircraft receiver.

R 1116A receiver,

a real museum piece.

This receiver, is what you call, a very old fashion radio receiver. A military design just after the “spark transmitters and receivers” episode  in WW1. They are very scarce to get now a days. That is why, it is one of my most favourite receivers in my collection.

The receiver is in an  entire original condition and working! Only the grid battery is a copy, see pictures below.

The R 1116A receiver is a later version of the R1116. It is a prewar aircraft receiver, which was used with the T 1115 transmitter. The aircraft was , for example,  the   British torpedo fighter “Swordfish”, which operates from aircraftcarriers at sea. The swordfish was wellknown  by actions against the German Bismarck, by attacking it with torpedo’s. Amazing fact is, that both the receiver and transmitter were placed just behind the pilot in the open cockpit. The pilot was also a radioman and gunner.

The receiver is a double superhet receiver. No  HF amplifier stage, just a tuned coil before the mixerstage,  first IF is 10,7 Mc, second IF is 100 Kc. The sensitivity is very well, and the bandwidth is small because of the 100 Kc frequency. Audio is sufficient because of the VR 35 final amplifier. My receiver is working very well . I’m using it also at the 80 meterband for AM, SSB and CW. Also provision is made for direction finding. The receiver can be switched  to 2  different parts, LF and HF. Each part can be switched into 3 different wavebands. Funny is, that the scale lightning  is changing by choosing either the LF or HF part, from the one to other scale.

The front of the receiver.


Another look at the under side of the chassis.  The LF stage and detector stage.


Just below the chassis Just left the variable condensors for pretuning the HF stage for the LF and HF part.


A simplified circuitdiagram of the receiver.  The diode at the input of the first mixer is for protecting the receiver for very strong transmitter signals. The diagram is only for one part and one frequencyband. It  has also a provision for an intercommunication  by means of the T7 microphone  connection. The preamp V6 and final  V7 is used then. V 8 is the CW oscillator. R 13 and R 16 are used for an external LF gain remotecontroll.

R 1082 pre war aircraft receiver.

R1082 receiver,

A real museum piece.

The receiver is all original from the out- and the inside.

Just like the R 1116 receiver, this is also one, which is a very scarce radio to get. A very simple design with only 2 tuned coils to determine the receiving frequency. One  for the HF stage, and one for the detektor stage. It is also, like the R1116 receiver, one of my favourite radio’s of my collection.

The R 1082 is a prewar aircraft receiver, used with the T 1083 transmitter. It is a TRF receiver , with 2 single coil  for each frequencyband.  One for the HF stage (below on the front) and one for the detector stage (above at the front). There are various freuqency wavebands.  The receiver could also been used for directionfinding purposes. For DF, at the head of the the HF coil, there is a symmetrical inputconnection for the cable of the loopearial. Directionfinding must be carried out  by means of  listing to the signal minimum. So no DF instrument. On the first picture a special (green) S-type coil (detector) is used. At the top of the coil, a spline cable for remote control can be attached. The meaning of this is only for readjusting the frequency a little bit. Only small  tuning is possible, otherwise you have to retune the HF stage also, when you make larger requency tuning.
It needs 2 volt for the heaters and 120 volts for the HT.


The above picture shows my receiver R1082. In front at the left the 2 volts heater battery and at the right  a couple of  coil sets for different frequency bands.


The receiver from the right side. Note  that  the aluminium case for the receiver  is put into a wooden case.


As seen above:  a close view of the front of the receiver. The cable for the PSU is homemade by lack of an original one.  The connector is made of a piece of teflon.


This is the coil set box, for the different frequency bands. A very hard to get box! Sure when it is complete and it is.


The schematic diagram.

R1082 a

The receiver R 1082 and transmitter T 1083 under test in an Australian Army service department.

Left the R 1082, right the T1083 under test.  Note the Aerial Artificial 1A on the shelve left, used as a dummyload for the T 1083.

FUG 16

Bordfunk Gerat Fug 16 Z

This set was build in 1943 by Lorenz.

It is a VHF transmitter, used in fighterplanes like Messerschmitt BF 109. But also the ME 110.

It was remote-controlled from the cockpit. The transmitter-receiver itselves was located in the balley of the fighter plane.

Also it could be used as a direction finder.

 Fug 16 Z front

Picture above:

 Frontview of the Fug 16 Z. Here you can see the servo’s for remote controlling the set. One at the right for the transmitterpart, to change frequency, and one in the mid, for shifting the receiver frequency about 30 Khz, up and down.

Fug 16 Z up

Upperside  Fug 16 Z. At the left the receiver part, in the mid, the LF part and at the right the transmitter part, with 2 valves RL12P35 in the power amplifier stage.

Fug 16 Z back

Backside Fug 16 Z.


The FUG 16 in the inside of the Messerschmidt ME 109 fighter plane. It was controlled at the pilot seat by a remote control.

Some time ago I purchased finally after years a original cabinet for it. I only had to buy the cabinet together with a FUG 16 ZY. Which was missing some parts in it. But now the FUG 16 Z is all complete and original. A separate cabinet is very hard to get and expensive nowadays.

See the pictures below.




                    The picture below is the FUG 16 ZY. Without a cabinet :). Maybe still a extra cabinet in future?




FUG 10

German FUG 10 airforce radio installation

FUG 10 means: Funk Gerät 10.

The Fug 10 is a very complex installation for communication  between airoplane to airoplane (Bord zu Bord) and from airoplane to ground (Bord zu Boden). It consists of several receivers and transmitters for the shortwave and long wave and a lot of remote controlls. In other circumstances it is combined with navigation purposes. (Peil G6 with EZ6 receiver, then called Fug 10 P).

The transmitters are very stable in frequency, by using special temperature compensating arangements  in the oscillator circuit. Consider, that this oscillator is not crystal controlled. The heat inside the cabinet is very high, because the principle is a MOPA transmitter in a very small cabinet. The oscillator valve is RL12P35, which much deliver much driving power to the power amplifier. This power amplifier has to deliver about 60 watts to the antenna at CW mode, by use of 2 RL12P35’s.

This arrangement was not only the use of ceramic material, but also a special condenser block in the circuit of the oscillator. These condensers had a big dielectric loss with a particular temperature coefficient. More about this a extended explanation n the post EZ6 DIRECTION FINDER.


Bordfunk 010

Displayed in the picture above my Fug 10 equipment. It is in working condion! I use the the short wave transmitter and receiver in the 80 meters amateur  band and made several contacts. The frequence stability is amazing!

Most units (EK,EL,SK FBG3, SchK13 and U10E ) are in working condition. Upper row “Funkerschaltkasten (switchbox), EK receiver  (shortwave 3-6 Mc), EL receiver (long wave 300-600 Kc). Mid row “Fernbediengerat” FBG3 (tuning the antenne tuners, switching antennes etc.), SK (shortwave transmitter), SL (longwave transmitter). Lower row “Eigenverstandigung Verstarker” RG 10 (intercom amplifier etc.) , “Umformer” U10 e (rotating power transformer for the receivers).At the back of the rack are placed, not visible on the picture,  the AAG2 antenna tuner and the transmitter  rotary transformer U10S.


Picture above: an older picture,  close-up of the units.

On the left lower row, a important control unit, the FBG 3, explained later in the post. At the front 2 knobs for tuning the AAG for matching the antenna to the transmitters for long wave and short wave. One knob for long wave (blue) and the other for short wave (red) . This knob is mechanical attached to a synchro motor system. In the mid the antenna current meter. With the big switch, with scale, in the mid, you can switch the transmitters either for long wave are short wave and which antenna to be chosen. Normally one short  antenna f

or short wave, and a long antenna, the trailing antenna, for longwave. It is possible to change the long wave transmitter from trailing antenna to short antenna, so the short wave transmitter from the short one to the long one. This in case, one of the antennas is broken.


In the above picture you can see at the left de ADb ‘s (Anschluss Dose ). In this case a ADb13 type. It is a remote connectionbox for the microphone-telephones in the oxygencaps of the crew. At the right the U-10-e rotarytransformer for the receivers.


On this picture above,  you can see the trailing antenne  type AH-10. At the front of the “Funker Schalt Kasten” is a switch to move the antenna wire up or down. Also a indication meter is placed, for how far the trailing antenna is released.

FUG 10 met AAG3

The FUG 10 with the fully working AAG 3. Note that the trailing antenna is also there, which came later in the collection.


The AAG on the testbank. Just to be seen, the schematic diagram and wire connections.


The inside of the AAG. Left the vacuum relay. When pushing down the CW key, the relay comes up. When releasing, it falls down again after a few seconds. This is working very well and pleasant. Above the long wave variometer. Above the variometer, the indication scale of the tuned frequency, the same scale is on the FBG3 control. Both he scales are turning synchron with tuning.


Another view of the AAG. At the left, the short wave variometer to be seen. Just in the mid, the synchro -motor for driving the variometer coils. This motor is driving by a “Drehfeld  System” , a kind of electrical achs, coming from a same type of synchro in the FBG3. This synchro is turned by hand with a knob, with same scale as on the AAG, to tune the match.


A nice look to the vacum antenna relay. It can be activated (transmit and receive) by 2 coils, seen on the picture.


Picture above the AAG on the testbank. All wired up to let it work. The schematic left from it Lateron it was connected original to FBG 3. To see in the display of my FUG 10.

FUBL 2 system.

The FuBL2 setup, mostly used in the Ju88 heavy fighter plane, also in the Heinkel HE 111 bomber.

This FuBl 2 is a landing aid for the pilot, in landing securely on the landing stroke of an airfield.

Interested to mention is, that the receiver EBL 2/3 was  not only a common receiver for automatic landing purposes, but the Germans developed another system with the aid of this blind landing system, using the EBL 2, for bombing targets in England, a automatic blind bombing aid sytem. That was in the early days the “Knickebeinverfahren”, working on 30 Mc.  A later version was the “X-Gerat”, which worked at a higher frequency of 60 Mc. So this makes this EBL2 receiver an historical receiver, because of the special use of it.


The antenna system of the Knickebein transmitter. A complex system for small bundling of the radio beam.

But first the explaination of this blind bombing system Knickebein,  in a easy way:

The principle is,  directing  a small bundled radiobeam, transmitted  by a very smal bundeling antenna system, just over the target to be bombed  The bomberplane just had to follow that beam, till he arrived  at the target. The pilot could follow that beam on a special instrument, called type AFN1, connected to the EBL2 receiver. This receiver, used in the early days of the development, was tuned then on the frequency of that radio beam Transmitter. The first trials consists of only 2 beams. See the picture below.


Two beams were positioned just across the target. One transmitter in the north of Germany and one in Germany, close to th Dutch boarder.

That radio beam consists of 3 parts, eg one narrow beam an two lobs. One outer, a lob with a dotted  signal. In the mid, a constant signal ( equi-signal) , the other outer lob with dashes. The pilot only had to steer his airplane that way, he only heard the equi-signal in his headphones. If his airplane was to far away from the equi-signal, he heard either the dots or the dashes.

This beam was called the Lorenz beam. This beam was a standard common used signal, comming from a transmitter, just in line with the landing stroke at the end of it, for blind landing systems. By navigating  on a instrument, the pilot could make a save landing on the landing stroke at night time and foggy weather. This in case of blind landing on the landing stroke.


The principle of the Lorenz beam.  The  3 typical beams. The mid dipole establish the main beam, equi-signal, the outer , switched reflector elements, did make the two lobs for the dots and dashes.

Below in the picture, the antenna system system.

A further improvement was the X-Gerat, which replaced the EBL2.

In the first trials, with Knickebein, with only 2 beams, the pilot flew along one of the beams on the equi-signal. Till he approached the the other beam. He heard then  first the dotted signal of the second beam, after a while its equi-signal. Now he heard only a mix of  equi-signals and released the bombs by hand on the target. He hoped, the bombs were on the target, it was not that secure.

X-Gerat was more secure. It used other receivers, see picture below. Picture taken from the museum of Arthur Bauer Duivendrecht.


It used more beams, see picture below. It used one leading beam, called Weser, just over the target, and three other, called Rhine, Oder and Elbe. The first leading beam (Weser) was in Germany. The other three at the coast of occupied France.

Picture A. In the mid the 3 beames, responding to the distance to the target. At the left the X-Uhr indications.

These three beams crossing the leading first,  just before the target location, viewing from the position of the bomberplane. The crossing of those beams gave an indication of the position of the airplane.

First  look at the AFN1 instrument in the picture below.


There are 2 needles on the scale of the instrument, a vertical one and a horizontal one.

The vertical needle of the instrument indicates the first leading beam (Weser), I mentioned. When the needle is just pointing to the dot, the plane is just moving into the right direction to the target. It is the leading beam.

On the left side of the instrument scale,  there are 3 dots. The dots gave the position of the plane, when crossing one of  the 3 beams.

See above picture A: when the airplane reached the first dot (Rhine) That is is a position close to the target, about 30 km. If the horizontal needle points to that dot, a lamp is lightning just above the centre of the AFN 1 scale. This is the moment, the first hand on the stopwatch is running. See the view of the Knickebein Uhr scale. After crossing the second beam (Oder), about 10 km before target, the first hand is stopping, the second hand is starting to run. When  reaching the thirth beam (Elbe), about 5 km before target, the third hand is running, the second hand stops. After the third hand is reaching zero, they pushed down a knob on a that Knickebein Uhr instrument.  Then afterwards the bombs are automatically released and went to the target. The bombs should reach their target now. Without seeing the target when for instance the sky is cloudy or foggy.

So for each chosen target, the leading beam is repositioned.

This stopwatch was calleds the Knickebein Uhr or X-Uhr.

This was a much more accurate system then the Knickebein system.

A nice told story of counter attacks of the British for disturbing  Knickebein system , was:

They used diathermy apparates from Hospitals, which had about the same frequency of the Lorenz beam transmitter. They modified it to the same frequency, modulated it with the dots and dashes signals etc., and sended it  by a small beam in the direction of Germany, so simulating a false Lorenz beam. The placed this modified transmitter hust at the leading beam and pointed the lorenz signal of it into another direction. So directing the german aircraft to another direcrtion.  Mostly the German pilots picked up this false signal, and could not find the second one, thus missing the target.

Ln 28901 (1)

Ln 28901-1

The “Knickebein Uhr” or “X-Uhr”, a  very rare item.

Bernhard/Berhardine navigation system.

Another use of the EBL 3 and EBL 2 receiver, normally used for  the FuBl 2 installation,  is also very interesting. It shows the very big knowledge of German engineers in developing all kind of navigation systems.

Especially the EBL 2 was very sensitive, to sensitive for a normal communication receiver. This because of several HF stages.

The EBL 3, type H or F, were used in another complex navigation system for the Luftwaffe to assist fighter planes for the  interception of enemy bombers.

The purpose of using this new system was that, the Knickebein, the X-Gerat and Y-Gerat systems could not used any more because of heavy interfering of British disturbing transmitters, described for instance in the post, the Knickebein system.

They wanted a system, which could not be disturbed, or at least very less. The Knickebein system was fully out of order.

This was called the “Bernhard/Bernhardine” system.

They started to build the systems in 1941 by Telefunken.


Picture of a Bernhard beacon system, at Bredstedt in the far north of Germany, with its hugh antenna system of 28 m high. You can make an impression of it by comparing it with the persons at the front.


Also north west of the Dutch village of Schoorl, at a high dune top at the north sea coast border, the remaining ring  of a Bernhard system. Here to be seen a circular part of the rail. Picture taken in 1980. The ring was broken down in the 1990’s however. But on internet, several remaining rings from France, Danmark, Germany, Poland etc. can be seen.

The system comprises a beacon station at ground level and a Hellschreiber printersystem in the aircraft. Bernhard was the FuSAn 724/725, the Bernhardine the FUG 120.

Why a hell printer system? Hell data is very safe system.  You get only a good data on your Hell system, if the hell information data are just Hell data. If it is not precise, the system does not respond. So what you read on the paper is really true!

See picture 1 below the whole system.


Picture 1.

At the left of the picture you see the Bernhardine system, at the right the receivers EBl 3 and EBl 2. This complete system with the EBL’s was placed in the aircraft. The main job of the system was to print the azimuth position on a special Hellschreiber printer. The receiver EBL 3 was a H (hand) or Remote (F) type. The F type had a separate channelbox controll. With this box,  channels could be chosen, the last two were chosen for the Bernhard/Berhardine system. See also the picture of my FuBl 2.

Frequency range of the receivers and system was 30 – 33,1 Mhz. The both transmitters of the 724, did had a power of 500 watts. The power of the 725 was up to 5 KW. They nearly had  the same frequency, about 10 Khz difference,  so the signals could be heard easily on one receiver only. The dimensions of the Bernhard system was about 28 by 35 m. The diameter of the circular rail was 22 meter. The weight was about 120 tons.

At the left side of the picture, you see the Benhard system, a very big rotating antenna system, which was driven by two electrical motors on that circular rail of 22 m in diameter. At a speed of  two rev/minute. The Bernhard consists of two antenna sub systems, both dipole arrays.

One dipole array of the most lower part of the antenna, is transmitting continuously data in Hell format (identifier and momentary antenna azimuth, or a short text  message, coming from one transmitter. The center line of the beam is the azimuth position of the antenna, referring to the null, being the true north.

The second larger dipole array field, the most upper section of the antenna system has a twin beam radiation, coming from the other transmitter. The pattern has a small null between the 2 beams. This null is aligned with maximum of the single beam, this antenna sends a continuous AM modulated tone. This position and the dip, could also seen on a remote instrument, the AFN 1.

See figure 2 below, to see the different beams.

hell-bernhard-prncple-ant-prnt (3)

hell-Bernhard-sig-plus-azim (2)

Picture 2.

So the Bernhard is the transmitting part with 2 separate transmitters and the Bernhardine the receiving part, with the EBL3 receiver for the azimuth position and/or short messages. The EBL2 receiver for normal navigation.

The Hellschreiber printer in the aircraft prints two parallel tracks on a piece of paper. See picture 2 at the lower part above. The printer starts to run, when the first lob of the second beam strikes the aircraft, the second lob did stop the printer. The lowest picture in picture 2, is a real photograph of the printout.

The lower track of the two tracks, prints the azimuth value of the single beam , when the beam “strikes” the aircraft for a few seconds, eg. when the centre of the two beams is just pointing to the aircraft. In this case about 255 degrees. Null degrees was referred to true north. Which was remarkable. A station letter, also is printed (M) every 10 degrees.

The upper track prints the signal strength of the received continuous signal of the two beams. It shows a very sharp dip, at which point, the exact azimuth value is given.hell-HS120-LH-front

The dual trace Hell printer HS 120, on board of the aircraft.

The Bernhard/Bernhardine system was a medium range system. At a altidude of 4000 meters of the aircraft, the range was still about 350 km. At a altitude of 8000, it was about 400 km.

Note: Most of the pictures are from the website of Frank Dörenberg.

My FuBl 2 display.

This picture below represent the normal blind landing system, left the EBL 3 F (Fernbedient), at the right the EBL 2. Als to be seen, the channelselector of the EBL 3 F, the FBG 2 for 34 frequency channels , the AFN 1 indicator and right the U 11 rotary transformer.

The last 2 channels were used ev. for the Berhardine system.

FuBl 2 panel.

As a FuBl 2 installation, the EBL 3 beacon receiver is working together with the EBL 2 marker beacon receiver. These 2 unit can’t work seperately. In this  situation, the Ebl 3 receives an automatic gain control (AGC) signal of the EBL 2, and the EBl 2 receives the audio signal output of the EBl3.

All together it was the code name LFF, Landes Funk Feuer.

When the EBl 3 is to work with the Bernhardine system, it is called then NFF, Navigation Funk Feuer, The FUG 120 takes over the place of the EBL 2. This is done by the SpKf 1a  mode switch (picture 1). This switch is re-configurate  the LFF to NFF  by the switch box UG 120. The EBl 3 gets its AGC input signal from the FUG 120, and the FuG 120 gets its AF output from the EBl 3.


                The inside of the EBl 2 receiver. Watch the special connectors, called Kabelschwanze in german language.


Above left.


Above right.


Behind the front cover.


Below the chassis.

The EBL2 module from the inside.  Also a lot a  valves for the HF stage of the receiver. The sensitivity of the receiver was very increased comparing it with a normal receiver.

I managed to let the EBL 2 working. But the receiver part cannot exist without the the EBL 3. Discribed above. Also inside the EBL 2 some LF parts With a very selective audio filter.

EZ 6 direction finder receiver.

 Direction finder receiver EZ 6


Overall description of the receiver as a direction finder.

This is a receiver, part of the Geman “PEIL G 6” aircraft installation called  “Peil Gerat 6”.

It was used for navigation/directionfinding purposes in large aircrafts like the Heinkel HE 111, Junker 88 and so on. It was common for EZ6, to be combined with the Fug 10, where it would have b

een placed instead of the E10L receiver. This was called the Fug10P (Peil).

There are 3  frequency bands: 150 -300 Kc, 300-600 Kc and 600- 1200 Kc.


Photo above: front of the receiver

  • Upper left knob: A2 is AM, Eich is calibrating the frequency, A1 is BFO is used by navigating, Bandbreite is making the MF smaller.
  • Upper right knob: Entrubing is cleaning the signal from “humm etc.”
  • Middle knob: tuning the frequency.
  • Lower left knob: gain controll.
  • Lower right knob: arrow is navigating by a double needle instrument type AFN2. Circle is “Rund Empfang, frequency band 300 -600 Kc. Communication purpose as a replacement band for the E10L.
  • Lower middle: connection for headphones (left) and test entrance for test meter PV10 for measuring the internal voltages.
  • Small upper right panel: Behind the trim pot for calibrating the frequency scale.

The inside of the EZ 6 receiver.

Note the text on the pictures for removal of the various part blocks and connections.

 EZ-6 003a

The front with cover panel removed.

EZ6b 012a

The block units from the receiver from behind.

EZ-6 010a

A connector of a unit.

EZ6b 002

EZ6b 010

Here to be seen the contacts of band switch.

EZ-6 015

EZ-6 020a

EZa-6 001

Right the opened oscillator unit.

OSCb 001

Oscillator case with circuit removed.

OSC 001a

The removal of the oscillator ceramic plate. The green points are the data, where the wires, comming from behind the ceramiec plate, have to be desoldered.

OSC 004

The three wave band coils of the oscillator. Above in the picture, the metal cover of the coils.


The three coils explained.

OSC 001b

The connections of the coils, the grid, anode and coupling coils. Very handy for measuring the coils.

Temperature compensation for to stabilise the frequency of the oscillator circuit of the EZ 6.

All the components of it are mounted on a ceramic plate as a printed circuit, which was very revolutionair  in that time, nowadays very common. This has a very good effect at changing wiring capacities, due to warming up of them. Also mechanically very stable to heavy shocks.

Other provisions were these ceramic condensers in parallel , which have a temperature coefficient control. When they get warmed up by the air in the small cases of equipment, their capacity values changed that way, that frequency stability of the oscillator is improved.

These special condensers, you can see in the picture above, the green and brown condenser blocks.

On the printed circuit plate of the oscillator ceramic plate in the left side of the picture above, you see these green and brown  condenser blocks. All ceramic  condensers, in parallel, are placed over the the inductancies  in the circuitry.

About these condenser blocks, there was another type with ceramic ones with different specifications . Different from these of the temperature coefficient types.

It is so special, that I like to tell something about it.

One is a special, great type of ceramic condenser, which proof the great knowledge of German engineers in that time. Consider, it is now more then 70 years ago!

These were made by the German manufacturer Hescho, who patented it, and made also the ceramic coils holders and variometers.

The ceramic condensers are very special made. In fact, they are very bad condensers with a big dielecric loss with a particular temperature coeficient.

The principle:

Let us look at the internal capacities between the anode and grid and between kathode and grid, eg.  Cga and Cgk,  of a radio valve. When the radio valve is warming up, and getting warmer and warmer, when it is delivering power, the anode dissipation is increasing, these capacities are changing, the value is getting higher. So the frequency of the oscillator is changing and getting lower. Characteristic curves and values are well known for each type  radio valve.

Now we look at these special ceramic condensers. When HF energy is applied on these condensers, by the energy of the oscillator,  the dielectric electric losses of it changes by heating up of his body, so the value of capacity getting lower.  Hescho managed to measure that amount of dielectic loss in these capacitors. so they could produce a large variety of different losses factors  in the capacitors very accurate.

 That is just what we need to compensate the frequency change, established by the warming up of the valve , so the anode, by the increasing anode dissipation. This proces is acting much faster, then the influence  of the temperature compensating material, in circomstances that the valve is switched off, so cooling down, and later switched on again. Consider, that the remainig heat in the cabinet of this valve is still reaching the temperature compensation material, while the valve has been already switced  off for a while.

So they made the curve of  these combination of condensors that way, by putting several of these condensers in the circuit, that it is compensating the changing valve curve. So frequency stability, needed in such circumstances in the airplanes, was increased well , especially in these oscillators. Note that the German equipment, especially transmitters, were not crystal controlled by lack of crystal material, which had to come from abroad and was of course not delivered almost in that war time.

But these condensers were probably only made for oscillators, not crystal controlled, of transmitters.

You can see this arrangement in the various transmitters for navy, the LO40K39, the MOPA transmitters of the FUG 10, S10K and S10L. Even, I saw it in the oscillator part of transceiver FU Sprech- f of the army. But these were probably only condensors with a temperature coefficient. In these MOPA transmitters of the FUG 10, this stabilsation method is most effective. The heat is much in the transmitter cabinets. The oscillator stage, a RL12P35, had to deliver much driving power, so getting very warm, by his big anode dissipation, for driving the power amplifier of 2 RL12P35’s, to let this amplifier provide 60 watts on CW. Below a picture of the condenserblock in a S10K transmitter. In my working FUG 10, the frequence stability is amazing, while the transmitter cabinets are pretty warm. The oscillator is of course not crystal controlled!


The condenser block of the S10K transmitter. At the right, a kind of printed circuit on the ceramic base.

I don’t think these condensers with that dielectrice loss were used in the EZ 6. Because it makes no sense. The oscillator in the EZ6 uses a low power valve, the RV12P2000. It delivers low energy to the mixer stage. So warming up of the anode is limited, so his internal capacities. But it might have been? I don’t know.

After the war, this manufacturing method of this special condensor was lost and forgetten. A synthisized module was used in oscillators. The frequency stability of them, depended on a crystal controlled reference oscillator. In fact a pity, but it worked well.

De EZ 6 as a direction finder.


Here the EZ6 receiver  as my “Peil G6” installation. Just at the right above a controllunit. With the switch you can do an automatic DF ,with the amplifier V6 just below the EZ6 and you can do a DF by hand, using the big knob on it by turning it to the left (L) or to the right (R). The DF antenna will turn to the left or right .Also the speed of the motor can be tuned. Right below the rotarytransformer U11 for the powersupply. In the middle the DF instrument type AFN2. Just all above  the motordrive for turning the DF antenna. Also seen the sense antenna. The complete system is a homemade version, except for the PRE 6 motordrive.


The AFN 1 instrument. The vertical needle is pointing to the dot, when the airplane is at course. The horizontal needle is for the signal strenght of the beacon transmitter. Tuning at maximun signal of the receiver tuning.


The DF antenna system. Above the sense antenna (homemade), below the PRE6 motor  drive unit.


Bordfunk 008

The PRE 6 motor and drive unit above and the ferriet antenne, just below the sense antenna, which is homemade one, by lack of the original one, but works very well.

This whole installation (certainly not original) is setup by my own and in fully working condition. The receiver is fed by the U11a by 24 volts DC. You can find the correct direction by rotating the little ferriet antenne  and watching the AFN 1.

BC 788 C

 BC 788- C altimeter transmitter/receiver.

 SCR 718-c

This is an altitude measuring system, consisting of a transmitter receiver type BC 788 C, SCR 718 C and an indicator box with CRT. The height in feet of the aircraft above the ground, can be read on the scale of a circulair trace  of a CRT screen. Indicator type I-152-C.

The SCR 718A is an American radar equipment designed to give a true measurement of height above terrain at altitudes from zero to 40.000 ft.

It is a pulsed altimeter type. The transmitter has a pulsed output signal.

The principle is obtained by measurement of the time of travel of a radio pulse from the airtcraft to the ground beneath it, and back to the aircraft.

On the low range altitude , 5000 ft range,  98,356 pulses of transmitter power are sent out each second. (Reference stage),

The transmitter signal has a speed, equal to the light speed.  The electron beam must travel in (1 divided by 98,356)  10.167 uSec around it circular trace on the CRT screen. Direction clockwise. This is precisely the time required for the transmitter pulse to travel to earth and back to the plane at an altitude of 5000 ft. The scale at the CRT screen is calbrated in 0 – 5000.

So if the reflected puls is at 2000, the altitude  is 2000 ft then. When the trace select is at “one time”

This system is a kind of pulsed radar system. The transmitter sends a pulsed signal from the antenna dipole down to earth. The receiver is picking up the reflected pulsed signal. Two pulses are shown on a circular trace  on the CRT.  The transmitter puls or reference puls, zeroed at ground level,  is at the zero point of the scale of 0 – 5000. The reflected signal is shown then somewhere furtheron the trace  the circular trace of the indicator.

Actually there are 2 scales .  To be chosen bij a switch, “one time”and “10 time”.  Eg. 0- 5000 ft and 0 – 50.000 ft. This switch is located at the above-left of the frontpnel.

In both scales, the zero point must be calbrated with the airplane at ground level bij de the knobs “zero one time”and zero “10 times”, located at the right side on the frontpanel.

The accurancy is 50 feet + 0,25 % in all ranges.

The power supply is 115 volt by 1500 – 2400 Hz. For this supply I use a home build power supply of 115 volt 1500 Hz. This power supply can be used for all kind aircraft equipment which desire a power frequency between 1500 and 2400 Hz.

The transmitter frequency can be tuned from 420 – 440 Mhz. The pulses are transmitted with a P.R.R. of 98,356 per second.

For the transmitter stage, only an oscillator stage, a radio tube type 6J6 is used. A pulsed power of about 8 – 10 watts is delivered to the dipole.

I managed to let the whole installation working a bit. I get a reflection on the screen, the reference lob or the transmitter puls. It can also be zeroid at the beginning of the scale. But, because the installation is always at ground level in my case, no heights can be measured. But no trouble, it is nice to show this in working order. So it is not fully calibrated at all.


 The front of the altimeter installation, which is in working order.

Left the transmitter/receiver BC 788-c and right the indicator unit I-152 c.

Note, that the  height scales on the screen are circular for an accurate reading.

In the picture below, the transmitter puls  shown at the zero point on the 5000 ft scale. Switch on indicator front at “one  times”.

Note that the puls is somewhat wide.

20230420_183950 (1)

In the picture below, the transmitter pulse is shown  in the ‘” times ten” position as a small pulse..


Here the original antenna, type AT-4. One used for the transmitter and one for the receiver. They were  mounted just under each wing of the airplane. Sometimes under the fuselage.

The dipoles antennas for transmitter and receiver, are mostly places each under the wings of the plane. The type number is AT-4. See picture below.


Some pictures of the altimeter indicator, at the lower part of the picture.

3957-2cmyk (1)

Here above a picture of the I-152 indicator at the Navigator position of a B 17 bomber. Mostly the indicator was placed at the Bombardier position.



Picture left, the  indicator I-152 at the pilot position of a fighter airplane. Normally it was used on bomberplanes, but now a special situation, The fighterplane is also used to protect the bomber squadrons, so flying at large altitude.

SCR 274 N – ARC 5 – AN/AR 8.

Aircraft radio SCR 274 / ARC 5.

The SCR 274 was the AAF, Army Air Force, radio installation, ment to use for short distances from one aircraft and the other. Also for communication in the neighbourhood of airfields.

Used in aircraft like Boeing B 17, the Flying Fortress.

The ARC 5 was used by the Navy aircrafts. Mostly, they were black in color, while the SCR 274 was just an aluminium color.

 SCR 274 N

This is my SCR 274 in working condition. On the left the 2 transmitters, in the mid the rotary transformer for the transmitters,  receivers and the controlboxes. At the right the ARC 5 VHF transmitter, type T-23/ARC5 and receiver type R-28/ARC5. Also on the right upper a control box, type C-30/ARC5, for the VHF receiver R-28 and transmitter T23.

Side view SCR 274 N

Above at the left  the antenna relay, 2 transmitters, 3 receivers, one rotary transformer for the transmitters and the control boxes.


Left the T-23/ARC5 transmitter.Inside very beautiful with the 829 B valves.


At the left an intercommunication amplifier, type AM-26/AIC. Also some spare items.

Marker-Beacon receiver AN/ARN 8


This is a very old Marker-Beacon receiver type AN/ARN 8. It is functioning on 75 Mhz and gives the pilot an indication of the position of the aircraft above the airfield’s runway during it’s landing process.

AAF Liaison radio

Liaison radio transmitter BC 375 E.

It was used in aircrafts like Boeing B17, B 24. during the second world war. Often in conjumction with the receiver BC 348.

It also uses a rotary transformer power supply, which I also own,  at  a voltage of 28 volts. Frequency bands could be chosen by different, so called tuningboxes. For working on a different frequency band, you had to pull out the tuning box unit in use from the transmitter and insert another one. All provisions were included in the transmitter to match the ouput stage to the end feeded longwire antenna.

It was placed just under the operators table. On the table the receiver BC 348 was positioned.

I use this transmitter often in the 80 meter amateurband on 3705 Khz in phone AM. Output power 100 Watts, anode-screen modulation by a carbon microphone. As a powersupply, I use a homemade mains supply.

BC 375 E

My BC 375- E  transmitter for 28 volts DC.

BC 375 buizen comp

Valves transmiiter, left VT 25, on the right four VT 4 C.

The VT 25 is the audio preampliefier. The most left VT 4 is the transmitter VFO and the other VT4’s are the audio power amplifier.Here the front cover of the valves compartment is removed.

The valves are glowing so much, you can almost read your newspaper in the light they are producing. A beautiful view, especially in the dark.

AAF IFF mk3g

 IFF transponder MK 3 g

This American transponder is for automatic identifying friendley or ennemy aircrafts. The transponder in one aircraft, sends a coded signals to the unknown aircraft. This aircraft, is responding then with another coded signal. If well detected , it is identified then as a friendly aircraft.


Above my BC966a IFF mk3G transponder. This was an  earlier type. Note the coaxial cable from the transmitter to the receiver part.



The two pictures above is the control-unit BC958a from the transponder. Just under the green metal plate, the destruction switch is hidden. When the aircraft would fall into ennemy hands, for instance it was hidden by ennemy fire on his mission, you could let explode a little detonator inside the transponder for destructing  the coding system inside. IFF was most secret.


The remote controll units. Left the type 965, right the type 985.

RAF H2S radar

H2S radar transmitters TR3191 and ASV MK7.

H2S was the British radar equipment on board of aircrafts of the Bomber and Coastal Command airforces in WW2 . The main part was a magnetron oscillator valve housed in a cavity resonator.

The type, seen on the pictures below, the TR 3191, was working on a wavelength of 10 cm. Later improved H2S systems were also used at a wavelength of 3 cm, like H2S MK 7, described at the end of this post.
The HF energy power was radiated from the bally of the aircraft to the ground by a tuned parabolic aerial. This earial was used by the transmitter and receiver part of the equipment. The reflected transmitted pulses, by the surface below, are getting back to the receiver input, rectified and fed to the indicator screen(CRT). On the CRT of the indicatorunit appears the forms of buildings, coastlines etc., were the aircraft is located above, just like on a map. So the crew/navigator knows then exactly the position of the
An  American version of H2S is the type H2X on 3 cm wavelength.

Of course H2S was most secret, so that is why a little explosive material, in a socalled detonator chamber ,  was put at the inside of the transmitter. In case of the possibl, falling into enemy hands of the aircraft over enemy territory, the explosive should destroy the inside of it. So knowledge about this technics, was kept away. The crew member could establish this by pushing a “detonator” button on the navigators panel, and electrically  fire the little explosive.

But you had to be very careful these days of war, with those units, found in aircrafts, which were shot down then . It was possible, that the crew members did not have the time to push the de detonatotor button in destroying the inside by means of those little explosives, when the aircraft was shot down.

H2S TR3191 front

  The front of my radar transmitter TR3191. which is complete and all original!  Also the case of it is it.

H2S TR3191 upper vieuw

 The upper view of the transmitter , with the fan for cooling the magnetron, below also the pulstransformer, which supplies the negative HT puls to the magnetron.

up Tr3191

At the left the diode mixer, where the signal from the reflected puls, coming from the antenna during the receive phase, is mixed  with the local oscillator signal, coming from the tuningunit 207 or from the indicator unit,  into a medium frequency signal. In the middle the rhumbatron, a TR switch, and at  the right the wave quide to the antenna outlet connector.

The switch is filled up with a gas and a little bit of water vapor. As soon, when the transmit phase is there, the high voltage puls is applied to the switch, the gas is conducting because of that puls and so cutting off the crystal mixer input. The reason for that  little bit of water vapor is to establish a quicker start of the conduction, so almost no energy is passed through.

The power energy, coming from the magnetron, is that high, it would damage not just the crystal mixer, but also the receiver input stage. So as a protection of it. Of course it  will let pass through the reflected pulsed frequency , during the receive phase, to the mixer. The gas in the switch  is not conducting in that phase.

Magnet magnetron

 Here the view of the magnet of the magnetron CV64, and the spark isolation shield. This spark isolation shield is nescessary , because of the high HF- voltage on the cathode side of the magnetron.Also to be seen,  the wavequide to the reflector feeder. The wavequide is matching the magnetron output impedance to the feeder impedance.

foto 4

foto 5

Here is very well to see, that the magnetron fits in the first part of the wave quide inside. Inside the wavquide is to be seen, output stick of the magnetron.

foto 6

foto 7

The magnetron CV 64.                                          Copper coverplate removed.

foto 10

Diode mixer.

foto 8

                                                                                        Holder with diode removed.

A x-ray picture of the CV 64.  Here we can see the several resonator holes. These holes are made in a big piece of cupper material. In the most above resonator hole, you can see the energy output link.

H2S mk7A, a 3 cm wavelength ASV radar.

Another radar transmitter used by the RAF, was the H2S mk7A, a 3 cm wavelength ASV radar. The principle was the same as the TR 3191. ASV means Air Ship to Vessel.

The purpose was to detect the German war ships  and especially the U-boats, which were at the watersurface, for charging their batteries.

This type was the TR 3523, which I own too.

The feeder itself, the connection between the unit and the parabolic antenna was not a coaxial cable anymore, but a wavequide feeder.( kind of hollow pipe). This because of the the short wave length of 3 cm. Coaxial cable will reduce the energy  to the antenna too much. By using this very short wavelength, the picture on the indicator screen

 I managed to find a lot of spares. Some missing parts were among them. Some chassis parts, to mount the fan, to mount the missing magnet at the back of the unit , the ring to fasten the magnetron on the internal wavequide and some internal covers. So it is now a bit more complete.

I am still missing the following

The magnet unit for the magnetron,

The tube or pipe between the fan and the air inlet of the magnetron,

The impuls transformer with the integrated magnetron 725 A.  I now mounted a seperate magnetron in my own way, without the impuls transformer. See also the pictures. It is of course not original.

Some original wavequides or pipes to fitt on the outlet of the transmitter.

Who can help me with these missing items? It is all a bit very specialized and maybe it could be regognized only  by the specialists among us, but who knowes.

Pse your re. in the comment at the end of this post. I would be most grateful. I sure like to complete this rare historical ASV radar transmitter.

2335 a

Front of the TR 3523.  At the left under part of the front, you can see the wavequide output flens.

2335 b

Side view, with left on the picture the 725A magnetron, attached to the  inner wavequide. Also the fan for cooling the magnetron.

2335 c

H2S TX 3 cm

Another side view and the back of the unit. Here to be seen the glass bulb of the magnetron, normally this glass bulb is integrated into the pulstransformer, so you will not see the bulb, but the transformer.

A close view ofthe magnetron,  which outlet is attached to the wavequide by a ring. Note, that the magnetron is mounted on a metal plate, which is not original. This, because the impuls transformer on his mounting is missing.


The 725- A magnetron. At the upper right, the outlet flens of the magnetron. The square part , with at the right the outlet flens, of the magnetron is a cavity chamber (inductance), which  resonance frequency is at about 3 cm wavelengh.

Modulator unit, type 64.

This unit is a very important unit for the H2S installation. It is used in verious versions of H2S. One of the functions of it, is providing  the negative puls for the pulstranformer in the magnetron transmitter.

mod 64 front

The front of the modulator unit.

mod 64 unit

Inside view on the chassis.

RAF Lancaster

Lancaster radio- and navigator section with T 1154 and R 1155.


In the past, the idea came to do something else with the T1154 and R1155 collection, instead of putting it just on a wooden shelf or something. On several sites on internet I saw that some people made a complete Lanc mockup of these equipment. ( Jan and Paul Bodifee at Deventer Holland and Norman Groom in the UK). This was something for me. But I did not had so much room, I got to remove my other radio’s to some where else. That was not possible. So I had to make it more smaller than the others. So this is the result in a smaller size, but still very nice. Of course the navigator section just behind the the wooden board of the wireless operator had to be there! And of course the T1154 and R1155 had to be in fully working condition to work other radio amateurs.



A close look of the famous and well known T1154N transmitter. Left the aerial switch type J.




The position of the various electronic equipment inside the AVRO LANCASTER aircraft in the late war years 1944/1945.


This is a view of the radio section of the Lancaster shown at the Imperial War Museum in London. The photograph was taken by myself during a visit of mine. This was the start of the idea making a Lancaster mockup of my own.



The radio operator office. Left the antenna

current meter for the HF bands, also the aerial switch type J.

Note the microphone connector on the front of the transmitter above. This special connector is a very rare one, very difficult to get.



Here a good look on the tubes compartment of the transmitter. Left the VR 105’s of the VFO and modulator. Right the VR 104’s of the power amplifier.



 A fine look of the transmitter from below.


 Side view.



Left the plot for the headphone/microphone for the oxygen mask of the radio operator.





The receiver R 1155 A. Note the centric tuningknob, Later on the 2 knobs were concentric.

Again a good look on the radiotubes of the transmitter.



This is a more closer look of the A1134 intercom amplifier unit and the Plugboard type 192. This plugboard can be used to connect the amplifier to several other equipment in the aircraft like TR1196, TR 1143 or TR9 transmitters and of course to the headgear/micorphones of the crew. At the right the receiver R1155 A.



Another look on the A1134 intercomamplifier. On the left the switch for putting it on the intercomeline to navigator, airgunner, pilot or let it function as a speechamplifier for the radio transmitter T 1154. Right the on/off switch of the unit. A small user manuel for using the amplifier on the forward side of it. The amplifier is fed for the filement from a lead battery and for the HT from a small vibrator psu unit.


nieuw 004

This is the direction finder loop antenna on the roof of the cage. It is a replica of the original one. A big “steering knob” with scale, placed under the skin is for turning the loop antenna .



nieuw 006

This is the navigator office. Above the well known Gee set indicator type 62. On the middle the API (Air Position Indicator)  unit just above the table. Above in the mid the compass corrector.



nieuw 002


A view of the Air positioning Indicator left . On the right side on the front 2 mechanical counters for the longitude and latitude in degrees and minutes. A mileage unit, fitted below the navigator bench, converts the forward air pressure from the pitot tube ( an open ended tube facing forward in the air flow) into a rotary speed such that this speed is proportional to the airspeed of the aircraft. A flexible cable couples this rotary output to the API and together with an electrical signal (compass bearing) from the master  gyro compass, produces an output on the 2 counters on the front, that read directly in degrees and minutes.

On the back panel several instruments. Also the IFF buttons for destruction the inside parts of the indicator and IFF unit in case of a crash behind enemy lines. 

See also right on the panel, a call button switch/lamp for telling the radio operator that the navigator wants access on the intercom. The radio operator also has such a call lamp. He noticed that the lamp is burning, so the he connects the intercom amplifier A1134 , which acted at that time as a speech amplifier for the radio transmitter, to the intercom line. So also the air gunner or the pilot has a call button with lamp.


e 003

On this view the VHF transmitter SCR 522 is shown. Normally it is not placed below the nav. bench, but I did so because of the lac of room. The TR5043 is the Brittish version of the American SCR 522 and in use in the later years of wartime. It is a 4 channel VHF set for “darky “communication, when the aircraft lost the navigation to the airfield. By this communication they could find there way back home when other communication equipment failed. Also visible is the control box withe the 5 red knobs on it. One for putting the set on (upper one) the other 4 for the choice of the 4 channels. Just below the switch for putting on the transmitter.

When nothing is working in the navigation installation, they could use the so called Bubble sextant at the right side of the table for determine the position of the airplane. This by the “old seaman way” by “shooting” stars in the sky and then reading the values on the sextant, then with these values determine you position on a map.

nieuw 001

Left the GEE Indicator type 62 A, right the GPI. at the left upper part of the picture again the compass corrector.

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The homemade tuning scale of the direction finder loop. The wheel is an original one. Above a cockpit lamp for illumination of the navigator office, which is not a replica..


nieuw 003


GEE receiver box with frontend unit ,below the voltage control panel no 3 as a regulator for the 80 volts – 1500 HZ from an alternator. The 80 volts is needed for the receiver box and the indicator unit.



e 002

A front view of the radio compartment, showing also the airplane skin.

GEE 266

Another GEE-indicator type 266. Note the blue switch on the lower right This switch can select more crystals instead of the one of the earlier type indicator no. 62.. The 266 was a later improved version. Main changes was the internal EHT power supply. This power supply was not there in the type 62.

mockup 017

The two dynamotors for the receiver and the transmitter below the table. The upper is the HT dynamotor for the transmitter, supplying 1250 volts DC, that one below the dynamotor for the receiver supplying 6 volts and 220 volt. The power supplies are being fed by a main power supply of 230 volts 50 Hz.

mockup a 002

Picture above shows the 2 HT dynamotor supply units, the above for the transmitter and the below one for the receiver.
On the left a homemade 2 – 100 volt mains supply unit for the A 1134.

mockup 011

The picture above is the crystal calibrator used in the Lancaster for calibrating the frequency of the transmitter T 1154. It is fed by the same 2 volt accumulator and vibrator power supply used by the A 1134 intercommunication amplifier.

Several internal crystals can be used, even a spare one at the front of the calibrator.


 sleepantenne Lanc 001

The pictures above is the trailing aerial of the T 1154 transmitter for especially the medium wave frequencies.


sleepantenne Lanc 002

Note the small balls at the end of the wire. They are lead balls, to let the aerial wire going down easier  because of the weight of it.

The lead to the J-switch has to be very well isolated by isolation standoffs because of the high HF voltage. Because the small length of the aerial wire is too  short for it’s frequency, the HF voltage at the beginning of the aerial is very high.


sleepantenne Lanc 003

sleepantenne Lanc 004

The wounded up aerial just under the radio operator table.

However, now a days, the mockup does not  exist anymore. About 3 months ago, I moved to another pace, a village about 15 km north of my former place. There was not room enough to rebuild it. I made a new setup. I kept all the item of it in my collection.

A picture is shown in the section “about”. But the T1154 and R1155  is still in working order. But as a remembrance, I left the mockup section  pictures and discription on this website.