FuBl 2 panel.

FuBl 2

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 to 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 landing aid receiver, 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.

Explaining this blind bombing system Knickebein in an 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 improved version was the “X-Gerat”?  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. Also unfortuniatly not mine.


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.


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. 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. The first dot (Rhine) is a position just close to the target. If the horizontal needle points to that dot, a lamp is lightning just above the centre of the scale. This is the moment, the first hand on the stopwatch is running. After crossing the second beam (Oder), the first hand is stopping, the second hand is starting to run. When after reaching the thirth beam (Elbe), the third hand is running, the second stops. After the third hand is reaching zero, they pushed down a knob on a that stopwatch  and afterwards the bombs are automatically released and went to the target.

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

A nice told story, what realy was happening,  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. 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”. Unfortunatly not in my collection.

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.

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 above for the Knickebein system.

They wanted a system, which could not be disturbed, or at least very less.

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 difficult to disturb. 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 right, of the picture you see the Bernhardine system, with the receivers EBl 3 and EBl 2. This complete system 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. Different 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 represent the normal blind landing system, used at airfields!


FuBl 2 panel.

Picture above: My setup of the FuBl 2.

On the left the EBL 3 F  receiver, a later version,  on the right above,  the EBL2 receiver. Just right below, the U 11, the power supply.  On the left below,  the AFN 1 indicator and the remote control of the EBL 3F, the FBG 2, for  a chosen frequency channel. There were 34 channels, the last two were used for the Bernhardine system.

As a FuBl 2 installation, the EBL 3 beacon receiver is working together with the EBL 2 marker beacon receiver. This is called the LFF , Landes Funk Feuer. 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.

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.

inside the receiver EBl 2.



                Added some new pictures of the inside of the EBL 2.  Beautiful                        construction.

The inside of the EBl 2 receiver.


Above left.


Above right.


Behind the front cover.


Below the chassis.

The EBL2 module from the inside. Watch that typical connectors. Also a lot a  valves for the HF stage of the receiver. The sensitivity of the receiver was increased comparing it with a normal receiver for blind landing. Note the typical connector, ” Kabelschwanze” called in German.

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

Discription of the complete combination of EBL 2 and 3 will follow soon.


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

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  1.  BC 788 C altimeter transmitter/receiver.

 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 obove the ground, can be read on the indicator screen (CRT), 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 feet.

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.

This system is a 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. The reflected signal is shown then on the circular trace of the indicator. When the aircraft is at sufficient height, there is to be seen 2 lobs on the circular trace on the indicators screen. On reference lob at the zero point and one lob somewhere at the trace, corresponding with the height, the aircraft is flying. At the  take off of the aircraft, when getting a height of about just below 50 feet, the reference lob has to be chosen by a knob at the front of the indicator, just at the zero point of the trace. The altimeter is now calibrated.

So there could be chosen 2 ranges on the screen, one till 500 ft and one for 5000 ft height.

The accurancy is 50 feet in de low range and 150 feet in the extended range.

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 each puls transmitted one complete timebase circleat the indicators screen  is effected.

For the transmitter 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. 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.

front BC 788

Here the front of the transmitter receiver. To let it work and having a indication on the screen of the indicator, 2 small whip antennas are used, one for the transmitter and one for the receiver. The connectors in the mid are left for the connection with the indicator and the right one for the power supply of 115 volt – 1500/2400 Hz.

indicator 1

This is the indicator I-152 c. Note the circular trace on the screen. There 2 ranges for reading the altitude. From 0- 500 ft and one for 0 – 5000 ft. ( about 1,5 km and one for 15 km). In this picture, the reflection point near zero is shown on the 500 ft scale.


In this picture, the reflection near zero is shown on the 5000 ft scale. Switch on indicator front at “10 times”.


Here the original antenna, type AT-4, used in my other altimeter equipment, the RT7-APN 1. One used for the transmitter and one used for the receiver. The were mostly mounted just under each wing of the airplane. Sometimes under the fuselage.

Some pictures of the altimeter indicator.

3957-2cmyk (1)

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


Picture if indicator I-152 at the pilot position of a fighter airplane.

SCR 274 N

AAF SCR 274 and Navy ARC 5.

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

Here 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.

RU 19 / ZB 3 / GF


RU 19 front

Here an overview of the RU 19 installation. Left the directionfinder loop antenna type DU- 1.


Radio Direction Finding Equipment type DU-1. Made by Bendix.

Suitable for using it with RU-19 series.


Left the receiver and right the transmitter. Above the receiver a homing receiver type ZB 3. The receiver is also suitable for directionfinding.

RU 19 side view

On the rightside of the receiver, inserted  into the receiver,  a tuningbox for a  frequency wave band, this one for the Longwave band.. There were several boxes, for all different wave bands, which could be inserted into the receiver. Some right on the picture some spare tuningboxes.

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.

ART 13 BC 348

AAF Liaison radio

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  1. Aircraft Transmitter T47/ART 13

Aircraft Transmitter T47/ART 13

The Collins’ ART 13 transmitter was used in large aircrafts like the Boeing B 29, mainly in the Pacifi in the second world war.

It was in use for both short-wave and long-wave purposes. The corresponding receiver which was used with the ART 13, was the BC 348.

The transmitter is a autotune transmitter, several pretuned frequencies (channels) could be selected. These setting could also be applied to the longwave channels. To be able to tune the antenna for longwave purposes, a longwave tuner was used.

The powersupply is a large rotary transformer, type DY12/art13 working on 28 volt DC.

The set could also (mostly in aircrafts) be remotely controlled by the type c87/art13 control unit. The pre-tuned channels could be selected by either the control unit or on the transmitter itself. Also at this box, a CW button was placed.

When used on longwave frequencies, a special longwave frequency oscillator unit was to be placed into the front of the transmitter (not seen on the photograph, now a spareplate mounted right of the 2 meters).

My ART13 in combination with my BC 348 is in fully working condition on 80 meters with an output of 120 Watts HF carrier (HF poweramplifier 813) (AM modulated (AG2 modulation with two 811’s in the modulator). Operating on Cw is possible as well. So far, I’ve made a lot of (successful) communications with other radioamateurs.

 mijn art13

Here you can see my ART-13 type T-47 ART-13 with the longwave antenna tuner on it. This is an old picture, taken in my former radio shack.

ART 13 BC 348

This is my ART 13 st this moment, the T47/ART13, which is an entirely new offset. The receiver in use is s a BC 348 Q on mountingbase. The mountingbase is a very scarce item her in The Netherlands. Picture was taken in my new radio shack. It’s doing very fine working in the 80 meter amateurradio band.

        Notice the tuner unit in the midle of the front for transmitting in the LW frequency band. By switching the transmitter to the long wave band, the vfo is directly connected then with the PA stage with 813 valve. The anode of the PA is then connected via a condensor to an oulet at the right of the transmitter. This outlet is then connected by a short wire to the long wave tuner, a CU 32/ART 13. or a CU26/ART13. See the pictures.


powers DY12

The original powersupply, DY12/ART13 for 24 volt DC.  Also the T-50 dynamic microphone. The ART 13 can be switched over from carbin microphone to a dynamic microphone by a switch, behind a panel on the front of it..


A new beautiful item, probably never used. The CU 26/ART13.

It is a tuner for the longwave- and mediumwave frequency band. Suitable for end feeded earial wires from 150 – 200 feet.

inside CU 26

The inside of the CU 26. Only containing a variometer inductance with several connections, a condenser and choke. Left themounting plate   CU 126/ART 13. In perfect new condition.

Another liaison radio is the 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.

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.

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

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  1. American IFF transponder MK 3 g

American IFF transponder MK 3 g

This transponder is for automatic identifying friendley or ennemy aircrafts. The transponder in one aircraft, sends a coded signals to the unknown aircraft, this ones is responding then with another coded signal. If well detected from the first, it is a friendly aircraft.  If not , then…….fire.at once.


Here is my BC966a IFF mk3G transponder. This was an  earlier type.



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 controllunits. Left the type 965, right the type 985.


The IFF set, shown here complete. Note the special coaxial cable from the transmitter- to the receiverpart.

H2S TR3191 front

RAF H2S radar

H2S radar transmitter.

H2S was the British radar equipment on board of aircrafts of the Bomber and Coastal Command airforces in WW2 . The mainpart 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 H2S systems were also used at a wavelength of 3 cm.
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.



This picture shows the front of one of my  H2S radar transmitters, which is not complete anymore. It is the  type TR-3191.
Several connecters are there. The opening on the left upper of the front is were the short coaxial cable(feeder) to the parabolic earial is put into. A part of this input connector is missing. At the right the input of the local oscillator frequency signal to the crystal mixer inside. At the mid, the input to the detonator explosive and for the tuning of the rhumbatron resonance cavity  chamber.

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.

A funny story about these  little explosives were around in the years 1950.

In these years, a lot of these radar transmitters,  were released and came in the various surplus stores. sometimes they costs only one british pound.  The story was told, also to me,  you had to be very careful with these units, there could be explosives inside. Of course that was not true, The explosive was already  removed from the transmitter, when they entered the surplus stores. So also yet removed from mine.

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 second radar transmitter TR3191. which is complete and all original!  Also the case of it is there.


H2S TR3191 upper vieuw

 The upside 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.

 This is part of the H2S installation. It is the tuningunit type 207 a.

The coaxial connector at the front, is the output of the local oscillator signal, fed to the radar transmitter. It is connected to a little link, inside the cavity chamber of the klystron. The klystron acts like a oscillator.



Upper side of the tuning unit. In the middle of the picture the klystron, as a local oscillator, whose signal is fed to the local oscillator input of the transmitter. At the right a rectifier valve. The knob at the left at the front, is the tuning of the resonance frequency of the cavity of the klystron oscillator, This by  a mechanical way, by  a little gearbox seen on this picture. The klystron contains also a little resonanc chamber. (cavity), which produces the energy.




This is the magnetron tube, type CV 64. The connection below is the output stick connection. The double connection above is the filement connection and cathode. In the middle the resonator cavity with cooling block . Below the output stick, that just will be placed then inside the beginning of the wavequide  feeder. The cathode is fed then with that negative HT puls. The anode is earthed, positive side of the HT puls.



CV64 en part wqavequide

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



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.

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 parts:

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 ofof

the 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  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


A half year ago, 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 my radio amateur colleys. It has to be noted that the whole mockup is still under construction, a lot of work is still to be done, but nevertheless some photograph’s of it.

A close look of the famous and wellknown T1154N transmitter. Left the earialswitch typ 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 Lanc 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 antennacurrent meter for the HF bands, also the earialswitch 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 poweramplifier.



 A fine look of the transmitter from below.





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.


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



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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.



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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 rotatery 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 mastergyrocompass, produces an output on the 2 counters on the front, that read directly in degrees and minutes. Just rught the four channel remote controlbox of the SCR 522.

On the backpanel several instruments. Also the IFF buttons for destruction the insideparts of the indicator and IFF unit in case of a crash behind enemylines. 

See also right on the panel, a callbuttonswitch/lamp for telling the radio operator that the navigator wants access on the intercom. The radio operator also has such a callamp. He noticed that the lamp is burning, so the he connects the intercom amplifier A1134 , which acted at that time as a speechamplifier for the radiotransmitter, to the intercomline. So also the airgunner or the pilot has a callbutton with lamp.


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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 Brittisch 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 controll 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 socalled 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.

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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 tuningscale of the directionfinder loop. The wheel is an original one. Above a cockpitlamp for illumination of the navigatoroffice, which is not a replica..


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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.



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

GEE 266

Another GEE-indicator type 266. Note the blue switch on the lowerright 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 powersupply. This powersupply was not there in the type 62.

mockup 017

The two dynamotors for the reciever 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 powersupplies are being fed by a mainpowersupply of 230 volts 50 Hz.

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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 supplyunit 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 powersupply 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 earial 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 earialwire 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 earialwire is too  short for it’s frequency, the HF voltage at the beginning of the earial is very high.


sleepantenne Lanc 003

sleepantenne Lanc 004

The wounded up earial just under the radio operator table.