1943 up to July 2012
This new page is an attempt to bring all data and facts together, and easing its access, as far as our commitment is involved
As to make approaching this webpage simpler I have decided to go from the top downwards in time. Thus, the younger the contribution the more it is placed on top of this page
Therefore, please follow the time-line from very down this page upwards
Started on 12 July 2012
After starting this list, I realized that it is becoming a rather comprehensive one. It reflects my activities and commitments rather well.
Status: 28 September 2012
After having tested the proper functioning of this new webpage, it appeared that a faster internet is very recommendable. As the very many flags (Bladwijzers) are opening often quite heavy loaded web pages, which have to open at least as deep as the flag on a page is hosted. When it is very down it, it may take time. Fast ADSL (DSL) and UMTS users will, however, not encounter much delay
Some links have been partly made red, as to distinguish them from the previous one in the same paragraph
For those interested in a slide show, please view also the Nachtfee Progress. A PowerPoint presentation converted into a PDF
2012 September We started with accomplishing matters discussed in our webpage: Things to be done culminating in a new webpage account: Things done. One major concern was, displaying the simulated Nachtfee system better; on the other way giving back for any kind of display its previous space occupied. We found a quite good space for it, partly next to the already existing aircraft wireless system, opposite we placed the simulated Nachtfee ground control, consisting of Nachtfee and a substitute for the Freya-EGON system as well as the ground receiver Gemse (Bladwijzer180). I also commenced a wide series of experiments, suggested in the Things to be done webpage. Some with success, though, others with less success, nevertheless necessary as to be able to determine what may have worked and what should have not likely. As to show what the various CRTs is about, I recorded a series of 15 video films placed onto YouTube. I my perception a unique chance showing what the Nachtfee system implications is about.
2012 23 July: Considerations started on matters which should be done in September or soon thereafter. I would like to measure the parameter R1 of the Nachtfee quartz involved. R1 is the series resistance loss of a quartz operated in series resonance.
2012 16 July: I reconsidered the unique Blohm&Voss P194 document. In which is stated: That the FuG136 aircraft display is remote controlled.
2012 9/10 July: A new consideration came up in my mind. Time has come to leave the Q5 channel at 500 Hz and using a different quartz controlled channel. Can we currently cope with this, YES, we can. The only thing necessary, is to implement an extra signal which is replacing the EGON signal. We have learned, that each successive quartz channel step is having a 2 Hz difference up or down. I have drawn a new hypothetical system concept.
2012 1 July: An annoying and lunatic discussion commenced, in which I had to become rather harsh, as someone is interpreting my current measuring results as: "He is having it right'! He is totally erroneous! It is out of the question, that (quartz stage) frequency is to be fine-tuned by means of overloading a quartz up to a point where it stops oscillating!!!
2012 30 June: For the first time special measurements were taken from a special test facility, in respect to: potentiometer setting versus frequency and its output signal painted on the scope screen.
2012 23 June: It has been noticed, however, that when the feedback was at is lowest level, that the quartz tended to drift its signal phase for a while after it was set.
2012 22 June: I started to interpret the reason for the existence of the control (potentiometer) build-in the quartz modules. I had already observed, that the signal output was at its maximum when the potentiometer is at its open end. Thus having its highest resistance. This already points into the direction of a negative feedback.
2012 21 June: The exact schematic of the quartz stage is drawn for the first time.
2012 20 June: Jaap Keijzer finally installed a kind of CRT window, which's concept is made such that several kinds of dual trace CRT of the HR2.... series can be adapted. We don't know the original one, thus he made a substitute with special adaptations such as for especially centring the various HR.... CRTs; from materials at hand.
2012 19 June: A new page has been established, dedicated to the quartz stages and their performance. Measured is extensively the warming up of Q5 versus time.
2012 9 June: Stressed, due to fears opposition of Hans Jucker as well as Günter König, I have setup a new page called Nachtfee hypotheses. For this I modified the existing Nachtfee block diagram in such a way, that three types of signals is shown. The red line constituting the common signal source. Its line is having in series the curious 'Phase' goniometer. The upper blue line is the data output line in which the 'order' goniometer is causing the phase-shift-vector to be set. The lower blue line section is the deflection system, having in series the "Rang offset" goniometer. Both the upper as well as the lower blue-line system staying in coherence. The yellow lines is the video or feedback system. It is also considered the consequence of dealing with two free running time domain sources. Günter believes that it must be possible, for instance, to adjust the two time bases in exactly equal phase, and then bringing one in the aircraft as to maintain synchronism between both time base systems. I believe that this will never work, especially not with 1940 technologies. Even today it would be hardly possible with normal quartz controlled systems. Leaving out, of course, Rb Cs standards. Two quartz controlled signal sources may theoretically running in equal frequency, though, their phase will most likely differ. Thus one never know whether two of such clocks are running exactly similarly. Also the existence of the Nachtfee 'Phase' control is discussed, as both Hans Jucker and Günter König neglect its existence. But in my system understanding its alignment onto the actual aircraft time base phase is essential. Again our current Nachtfee concept is discussed.
2012 8 June: The existing divider stage of 6 July is experimentally using a transistorised RV12P2000 substitute. It works, but not as sound as the RV12P2000 system. Maybe that optimising its circuit will improve its performance. Its experimental aim was only proving that it is possible.
2012 6 June: A frequency 2 : 1 divider is build successfully, using a regular single ended LF transformer ( 5 - 3500 ohm impedance). Its basic schematic is about equally used in the original Nachtfee circuit. It worked instantly. It tracks over a quite wider range.
2012 4 June: I decided that time has come to clean up all the rubbish which has culminated over more than a half year. My practice always is, changing things one by one. All the time checking whether it still works correctly. Including the entire system loop: Nachtfee - simulated EGON - FuG26a _simulated aircraft display system (FuG136) - FuG25a retransmission of the quasi EGON signal as well as the actual time-base-phase visible on the LB2 control screen.
2012 2 June: Tuning fork experiments. Although, I only possess a 1000 Hz device, experiments were carried out with it to investigate whether it could be lowered a bit in frequency. Which didn't worked out to be well reproducible. 1000 Hz is double the frequency where I am looking for, thus a frequency divider is necessary.
2012 16/17/20 May: An e-mail discussion started with Günter König. A quasi never ending discussion enfolded.
2012 12 May: I managed to replace the defect "Isolierwandler" number T3 (thanks to Dick Zijlmans'commitment).
2012 11 May: My friend Phil Judkins dug further in the AIR 20 2877 series at PRO/NA at Kew. They by the way, gave us permission to publish the transcripts on our website. I always wondered what the mystical expression on the Nachtfee 'order' or command scale may mean. Among the papers he send me was A.D.I. (K) 160/44. A most relevant document, which lifts quite some of its secrets. As in military service usually, all sorts of code-name-expressions are around. (Please scroll down on that page). Also very significant, especially in respect to the very little what is operationally known of Nachtfee, is: that Nachtfee was tested in December 1943 at Rechlin and that it later went to Montdidier in France.
2012 9 May: Just after my return from the Dresden meeting, where I met, among many other collectors, Hans Jucker. I started a new page. Hans Jucker is strongly opposing my views and is, on the other hand, boycotting it, as well as to take notice of our progress in understanding Nachtfee. He came up on the last breakfast just before we left, that they have used two signals being the Freya-EGON pulses and the Nachtfee signal pulses. The EGON pulse was synchronising the aircraft time base. A nice idea, but most likely unrealistic. I don't know where he got his ideas from, but it might happen, that when both pulses a having equal PRFs that both pulses are having equal signal phase. What may happen when the Nachtfee order is starting to be changed? In my perception it is likely that the FuG136 aircraft (aircraft display) is following the data signal and the the Nachtfee signal becomes acting like the EGON signal. It is also most unlikely from another point of view: when they used other than Q5 channels both the EGON (500 Hz) and the Nachtfee data signal having + n x 2 Hz frequency shift never can locked upon. A British Y-Station reported that they observed once an in-phase- and at another occasion that the Nachtfee data pulses (they had no idea what it is called) had fast moving signal pulses, thus having a different frequency. Please remember, that each quartz channel step causes two times a second faster moving pulses. This also implies, that Hans Jucker's perception is incorrect, as the FuG136 aircraft time-base should always being in phase with the Nachtfee ground signal.
2012 15/16 April: I continued testing the retransmission of dual signals; one being the simulated aircraft time base, the other one is is the recognition signal. It was also encountered that apparently the special CRT filament transformer (6.3 - 4 - 12 V) is the cause that several times the LB2 brightness potentiometer burned-out, and that it also caused the damage of the 1-2 kV transformer. It ultimately proved that it should be rewound, because above a certain voltage level it causes shortage against ground. Also the HT rectifier RFG5 was implemented in the CRT HT circuit. Was it likely that the Nachtfee data signal was at the same time acting as the Freya-Egon system pulse (PRF)?
2012 13 April: Continuing experiments with the Nachtfee data transmission towards the simulated aircraft display. Also finding a way, with minimal change of the FuG25a construction, by means of a single wire connected onto an empty pin of connector Bu1.
2012 7+9+10+11 April: Experiments done with dual feedback signal convey, as well as investigating some encountered difficulties with the Gemse receiver.
2012 6 April: Some experiments being commenced under different parameters. Especially experimenting how dual signals is displayed on the LB2 CRT screen. Also what their blip vectors are under different time and phase settings.
2012 3 April: Experimental feedback of both the Freya-EGON as well as the aircraft display time-base-phase; using the standard transistor set up but now with an additional signal input. Also the Nachtfee 'Phase' control adjustment on the dual trace CRT screen is being investigated.
2012 2 April: Continuation of simulating the Nachtfee data towards hypothetical aircraft display and feeding the time-base-phase towards the Nachtfee feedback input.
2012 31 March: The implication of the Jones report on my current system understand is reconsidered. Also a Lissajous firgure circle is successfully created. By means of Z-modulation the actual Nachtfee data signal is being made visible by means of a high-lighted spot. A wonderful photo of our experimental setup. Wires running freely from the various units, like power supplies, but also signal and data cables being involved.
2012 28/29 March: First experiments with sending a pulsed signal originating from the Nachtfee data output towards the FuG25a and its receiver output being feedback to the Nachtfee 'Impulsamplitude' input. Signal can be monitored on the LB2 control CRT screen. Also is being considered what British wartime sources knew about Nachtfee, although, they then did not know its code name.
2012 27 March: The FuG25a test rack (table) as well as the Gemse mounting frame were brought to the Klooster premise, where it is being connected such that it becomes an integral part of our Nachtfee-FuG136 experimental setup.
2012 26 March: Considerations on EGON. Freya-EGON. Starting with a series of hypothetical concepts, as to finding out what the most likely system configurations might have been. Up until now technical information is not yet found (may be, perhaps, never found). The only means is to imagine what may have been possible. For this it is my imagination that counts.
2012 21 March: After the experimental modulator worked well, it is time to build it in a proper Al box. Its principle is simple and is directly pulsed from the output of the TTi Pulse generator.
2012 18 March: After FuG25a worked well, my attention is drawn to the Gemse receiver, which not yet responded properly.
2012 16 March: Trials were carried out with several kinds of HF modulators. The normal (regular) modulator stage inside generators, like our R&S SMS is not capable of dealing with short signal pulses of a few µs duration. For this a special pulse-modulator has to be designed. It came out finally that a BD237/BD238 combination worked best, and is being used in several different modules successfully.
2012 12 March: The FuG25a testing rack (table) is wired and becomes under test. The transmitter is responding on to antenna signals. The mode- and key selector unit BG25a is also operational.
2012 9 March: I started with a new project, in which I would like to reconstruct the IFF system based on FuG25a and its ground receiver called Gemse. So that we, in a later stage, can close the entire Nachtfee - FuG25a - FuG136 - Gemse - Nachtfee system loop; and being able to simulate what its implications are.
2012 7 March: It was investigated how most likely the actual phase was adjusted at the dual trace CRT HRP2/100/1,5 A. It is still hypothetical, but nevertheless, the most convenient and likely way.
2012 5 March: I got very interesting papers from Mr. Fastner from Norway, which is about a Blohm & Voss project dedicated to a new fighter type P194 project. A project that however, never matured.
2012 1/3 March: Again attention is drawn towards the LB2 circuit, what may cause so much troubles? Time and again its brightness control is burning out. On 1 March I got a wonderful document send by Jørgen Fastner from Norway, containing a Blohm&Voss series of planning papers for a never built P194 fighter aircraft. First thoughts were given in to the easiest way of obtaining phase shift for the future painting of a Lissajous figure, aiming at a circle by means of the X and Y channels of our oscilloscope. Also the newly made dual Class -C amplifier using historical high-slope valve type EF14.
2012 27 February: Two special switches are build-in as to allow switching off the 450 V HT and the 1 + kV CRT voltage. I had already for safety reasons implemented a series fuse as to prevent damage of the HT transformer. Though, interrupting the 450 HT and switching it on would certainly blow-up the fuse. For this I did not switch directly in the HT line, but the 12.6 V of the two rectifiers is occasionally interrupted. In the beginning, when using the switch nothing happened. I looked closely in the wiring but could not find any trace a fault. It finally was discovered, that the EZ12 cathode is is heated up such that it keeps emitting electrons for more than 1.5 minutes! One may ask why using valve rectifiers and not using semiconductors? This would be most dangerous! Why? We have noticed that the operational HT is 450 V, this voltage or even more will be fed onto all valves as long as they do not themselves emit. The delay caused by heating up the EZ12 is a very necessary system parameter! I also started with the implementation of the FuG25a combined with the Gemse ground receiver. This implies that we have to reconstruct its system on testing tables some or less similar to what was used during wartime days. I made a kind of replica of the FuG25a testing rack. Also was being observed some aspects of phase shift as function of Range offset control and its implication on the 'Phase reference painted at the dual trace CRT HRP2/100/1,5A.
2012 24 Februay: I looked more in details to the implications of the recently (Eureka) discovered purpose of the Range offset control (formerly called 'Number scale).
2012 22 February: Eureka I finally have deduced where the strange number scale is being meant for! I mentioned on the web, maybe due a lack of adequate new information, that 500 Hz is having a wavelengths of 600 km. In radar terms this is 300 km. OH, may the strange scale having a scale from 0 - 300? YES it does! The 0 - 280 is to read as 0 - 300, isn't in a normal compass 0° not equal to 360° as well? Yes of course!
2012 21 February: I continued with hypothetical system reconstruction, based on what my actual system understanding is, combined with my imagination.
2012 20 February: A more historical reminiscence is my today's contribution. Also necessary as to bear always in mind the historical context of Nachtfee.
2012 17 February: I dealt with the problems of understanding the way of 'time keeping' was commenced in the aircraft. Quartz control, as is being used in the Nachtfee ground consol? Or, what I guess is a useable option, controlling it by means of a tuning-fork oscillator, which can be fine adjusted manually by means of a variable d.c. current. I will not, however, say that this had been the case. It is only my hypothetical perception, and may well being incorrect. But no one is actually knowing the eventual truth. I also started with a series of hypothetical system reconstructions. As to figure out which options maybe the most likely ones.
2012 13 February: Special attention was given to the moving door-lock mechanism. Extra attention was given to the way the two traces of the dual beam CRT should be matching together. Quite a breakthrough is the vertically back-to-back adjustment. This will prove that this is the most likely way which also the Germans may have operated it during the war. Continuing phase difference measurements versus the 'order' phase setting
2012 10 February: The adopted electrolytic capacitors were mounted more appropriately as well as extra care was taken to be sure that they were not being operated in at critical voltages. Also the cause of some burned-out resistors were figured out (was partly my own fault). Also direct phase shift was measured between Nachtfee and the external Philips 5190X synthesiser.
2012 9 February: General test were accomplished. Phase shifting is quite simple when we use two first order networks in series. After some simple trials it worked fine. Z-modulation replaced the electrostatic deflection way it may have been done during wartime. Also quartz frequency stability test were undertaken, as to measure time versus quartz frequency response.
2012 1 February: It was discovered, that when the external CRT HT was set > 1 kV that the LB2 brightness control (potentiometer) burned-out. This happened three times, but WHY? It was ultimately discovered that the reason was a shortage against ground in the separate filament transformer for the CRTs as well as the CRT HT rectifier. This was also the cause why the HT transformer was blown up. Dick Zijlmans had bought for me a Philips LF synthesiser which allows steps of 0.001 Hz. As so often on Marktplaats, one doesn't know whether the object is faultless, which wasn't the case. It has a minor but annoying defect, when it is cold started, its sine wave signal is having quite some distortion. After heating up this reduces to a more acceptable level, but never vanishes (my guess, an electrolytic capacitor). For the time being I am very pleased with it. Although, I soon encountered serious downsides. Have you ever adjusted upon an unknown frequency by means of a synthesiser? Programming demands: setting the sort of signal - entering the exact frequency up to 0.001 Hz accurately - then entering it; shit too fast or low - try it again. When doing this all the time is really making you mad.
2012 30 January: Time has come to investigate whether it is possible to simulate the Nachtfee display in the wartime pathfinder aircraft. The most simple means is to paint a Lissajous figure, when X and Y is having a phase shift of 90° it should paint a circle when both scope channels are adjusted appropriately in the mutual amplitudes.
2012 27 January: The complete Nachtfee block diagram is drawn. In the meantime my friend Phil Judkins traced a lot of Felkin reports, of which 357/45 is the most interesting one. Its partly dedicated to aspects of Nachtfee.
2012 25 January: Time has come to get the Nachtfee internal power supply operational again. Following the valve base layout, two kinds of rectifiers may have been used, either an EZ11 or EZ12, the more heavier type. The latter is the most likely one. More powerful, and just right. The two valves are wired as to act each as a single phase rectifier (both anodes pparallel). All experiments have been accomplished by using a variac so that the 220 V mains is variable. Starting up from say 110 V onwards. I was rather shocked after discovering that at about 220 V mains, the HT was about 450 V dc!! It was necessary changing some of the smoothing electrolytic capacitors. It ultimately worked well. It was also discovered, that formerly inappropriately working stages do respond now rather stable. A second move was taking the apparently defect HT transformer for the CRTs out off the frame. The cause of its defect will be discovered later, but gave me quite some headaches!
2012 21 January: After having had some unpleasant discussions, I decided to explain Nachtfee's working principle differently. Please view also the following drawings and text lines. For better understanding also the block schematic of the quartz stage is drawn.
2012 20 January: Michael Svejgaard supplied some section of an A.D.I report, which number I still don't know, but definitely is from Jones' Office (Sc). It for the first time states: that British Y-stations monitored Freya-EGON signals.
2012 18 January: My attention is drawn towards the circuit of the oscillator module, and why these respond so differently. Also the reason of implementing a potentiometer is considered. Although, it was not before the end of June 2012 before the oscillator circuit was made public as well as appreciated. It has to be noticed though, that still some are refusing to accept my measurements actually. Dick Zijlmans joined the first attempts finding out whether it is possible to operate the thermostatic oven again. It commenced all well, after having re-adjusted the two relay contacts as to cope optimally with the different demand (by adjusting the two relay contacts accordingly)
2012 16 January: It was now finally found that the signal output of the formerly called 'double size module' actually is dividing the oscillator signal by a factor: 1 : 15. Hence, 15000 Hz is becoming 1000 Hz. Clearly is also visible, that each quartz channel step generate 4 Hz steps up or down. Now the drawn schematic of what I earned is called: Regenerative divider is better understood. It is basically an oscillator, which grid current is synchronising its free running signal (locking upon its signal phase when crossing 0°). Following the 1000 Hz line and its successive stage, a third divider-stage is found, providing 500 Hz. We have altogether three divider stages first 1 : 5 followed by 1 : 3 finally, inside the Nachtfee main frame division 1 : 2 providing a 500 Hz. This frequency is equal to the Freya-EGON station PRF. It may thus have been possible, that the Nachtfee data signal is being used a Freya-EGON data signal as well. This will be kept so during our first series of trials.
2012 13 January: It was investigated more closely what the interactions between the small and big plexiglas pointers are against the click-stop attached onto the 'order' or command servo- goniometer. It is definitely found, that the big pointer is having no mechanical interaction onto the servo- goniometer. All the click stops, however, are in concert with the 'orders' printed at the paper scale. I suppose therefore its function only is acting as a mechanical memory. The small pointer is directly (1 : 1) coupled onto the goniometer axis. It only has a click stop pointing at North. We will later learn, that North has a function indeed, but only from where the 'order' or command pointer has to be moved from. It is also investigated what the interaction of using the 'Frequenzkontrolle' push-button and the signal on the CRT screens are.
2012 12 January: My first attention focussed onto the shape of the painted blip at the LB2 screen. It proved that first order signal differentiation does make sense. No provisions were in this stage undertaken as to block the negative edge of the signal slope, but the EF14 is not responding onto it too much, so it is being left this way for the time being. It was also watched what the effect of using the Freya-Polwender switch is. We knew already from simply tracing its wiring, that its only means is inter-changing the two output wires. Viewing its response made it clear that we are dealing with coherent signals, as this is the only conclusion possible. Its blip jumped from North to South, thus changed 180°! Without coherence this could never happen. My next move was looking what the purpose of the dual trace CRT might have been. This was then without doubt a rather expensive device, why should they have implemented it? It was found that the vector of the 'order' pointer is having an effect onto the time base line and the position of the feedback signal. But why, and how, should it be aligned and maybe adjusted against each other?
2012 8 January: 2012 8/9 January: Time has come to investigate whether the CRTs will respond on its internal circuitry. The CRT HT is delivered by means of an external HT power supply as well is the regular HT of about 250 V. This latter voltage will cause me a lot of problems, but who knew in advance how it otherwise should have been? From experience I expected correctly that like was done in the old days, the CRT + HT was connected straight onto ground and the negative line was connected onto a wire of which I guess correctly may be be used for it. The EL11 was starting to respond, but not yet fully as some blocking capacitors had to be bridged. It was also discovered that some kind of sabotage was encountered. This finding will be for us crucial, as it will lead soon to a real discovery! Also, we took time to replace the Freya-Polwender swith which has a broken handle, as well as looking how the brightness control of the dual trace scope is functioning. As is visible, it is done by means of three gear-wheels in which the middle one has to act as to keep the two outside ones in concert. I also tried successfully to spray contact oil inside the quite difficult to access 'Frequenzkontrolle' push-button. On this very day a new page Nachtfee-Inbetriebnahme is initiated. Which will finally leading to a great, even fundamental, discovery. Together with Dick Zijlmans on 4 January, I searched the entire afternoon where to what I designate pin ''b' of the three phase servo- or goniometer is going from on being connected onto. As usually, during being in bed half asleep, I found the solution; which may also for you very helpful! Take your dual channel oscilloscope and set it on: chopper and triggering at channel A. Connect one probe onto one end of a cable and search with the second probe all contacts until you find an equal signal with equal amplitude - signal shape or curves. When these are moved vertically over-eachother a single signal becomes visible; this definitely is the same signal line. Only by this means I found that a line was interrupted or being sabotaged. After having restored the interconnection between servo- goniometer point 'b' and its counter-point, I could for the first time watching on the dual trace scope that the 'order' pointer indeed is moving its signal phase against a signal reference of a previous stage. What an amassing day, feeling when you are about reaching new findings! What a Day! Having still in my mind that in some way sabotage could preventing the appearance of signals on LB2 screen, I connected the input of Rö7 (EF14) a capacitor and connected it onto various points inside the Nachtfee frame. At a certain point it was discovered that a signal blip appeared on the LB2 screen, which also could be rotated by means of the 'order' pointer!! It is now understood that the separate interface line is to close a signal feedback loop!
2012 3/4 January: My attention is drawn towards the circuitry inside the moving door; giving access to the 'order' or command servo or goniometer, as well as to the hidden components of the LB2 circuit. Following the various wires, it was already quite from the beginning that a coaxial line running from the 'List interface connector' towards the 'Impulsamplitude' potentiometer further to Rö7 (EF14) and then to the rear components of the upper deflection chassis on top. From there towards two high voltage and capacitive trimmer near to the LB2 section. What is more likely than feeding a signal onto the interface List-Stecker at pin 1? It was found out, that a single pulse was painted at about 260. .. Hz. Rather instable still. We know now that the deflection signal was not yet locked upon the quartz time base; but originates from the unlocked regenerative dividers. Nevertheless, we got a signal! Please watch a quite nice screen shot of such a signal. I searched the entire afternoon together with Dick Zijlmans for a missing wire-connection. Please notice what was done on 8 January.
2012 2 January: That we saw an ellipsoid partially was due to my own fault, as I read 6000 pF instead of 60.000 pF. Party understandable because the capacitor is mounted deep inside the quite inaccessible moving door. After having corrected my fault, a circle is painted on the LB2 screen. Maybe not yet correctly adjusted, but it works. My aim always is, to get things working first, albeit not correctly; it however gives a point from which one can watch what the interactions are. Also via a bridging wire the oscillator signal is shown on the LB2 screen. What we regarded being the oscillator signal will prove later to be of a different origin. On this very day I also started a discussion page after discussions with Helwig Schmied. Our disagreements lasting up to today. This will be, very sadly, not the only disagreements with others, which basically is owing to the fact that they have a concept perception but lacking the understanding of that Nachtfee really is about. All lacking the will going into it deeper or simply due to reluctance.
2011 27-30 December: My attention is now focussed getting the two CRTs running again. The small CRT is of type LB2, normally used in Liechtenstein b/c like airborne radar systems. Being of the magnetic circular deflection type. We only possess an LB2 without its Al head which is also aligning the CRT envelope against the socket pins. Very delicate, one mistake and the CRT is broken. For this I phone my friend Günter Hütter and ask him whether he can send me one from his stock. Within a few days it arrived and the LB2 was fit into its socket. What I never had realised before, I guess hardly anyone else, that the upper section of the Al head is having a slit, which can be illuminated by means of two miniature bulbs. On 27 December: My attention as dedicated to the deflection section of the dual trace CRT HRP2/100/1,5A. It was also figured out what the valve numbers were and recording them. The EL11 stage is showing saw tooth like deflection pulses (Please notice also the next screen shot) which will proof to be different, owing to insufficient HT and likely not yet properly functioning of the time base chain. For the first time a sign of life is becoming visible on the LB2 screen, although an ellipsoid is partly visible.
2011 26 December: The integral 'order' module have been replaced inside the Nachtfee chassis. Due to lacking assistance, a delicate job, a one is having only two hands, but we often need three or four of them. However, I managed without damage successfully.
2011 25 December: On Christmas day, I started with trying to refit the paper scale together with the plexiglas discs. It was also discovered what has caused the oxide as well as the 'water-shade' like deterioration on the paper scale. The paper scale had been in its lower section a bit too wide, thus reaching a few mm outside of the top plexiglas disc. It actually was being pressed by the metal ring. We know that paper is rather hygroscopic and when being stored improperly it easily can become humid to a certain degree. The Fe ring was over a long period pressed onto it and have started building up Fe oxide. This is the reason why the paper is showing brown sections, which are just opposite the ring oxidation sections. I cured it with cutting the paper just a bit such that it will not touch the metal ring any longer. After re-mounting it I turned the ring such that the oxide is facing towards the front panel. Luckily the German technicians had made the ring sufficient symmetrical. It was also considered whether it does make sense to produce a new scale, but the original scale is still worth being used as the original wartime witness. When we compare both the 2005 and the 2011 photos, it may show that the last owner may have stored it very improperly! I might have been stored in an quasi open shed, not well fit for historical electronics. But, nobody knew what it was, and that we could ultimately have made it working again is to be regarded a miracle!
2011 21 December: Dick assisted with dismantling the order module as to get assess to the paper scale itself. The paper scale was quite difficult to access , (please notice also the following up photos) as we needed special tools. Dick came up with the bright idea buying a "Syphontang" which is particularly fit for getting grip onto circular surfaces, like pipes and that like; as the black circular . It proved to be the solution. As the plexiglas (perspex) pointers are very brittle and should be handled very carefully. Maybe a few days later, but its exact date isn't recorded, the paper scale was cleaned from all sorts of dirt, such as oxides and other rubbish.
2011 14 December: Phil Judkins, had traced in the British Public Record Office, now National Archives, in Kew London, documents on Nachtfee just after Nachtfee was operational over British territories during the Baby Blitz between say January - March 1944. R.V. Jones' Office reported in Nachtfee, although, it was not knowing its operational code-name yet. A.D.I. (Sc) Report 101 In contrast to the Felkin papers, Jones' Reports were distributed first to the Prime Minister Winston Churchill's War Cabinet and his Scientific Advisor Lord Cherwell (formerly Prof. Lindemann). Please read the content of this link carefully, as it is most interesting material! With the help of Dick Zijlmans we could turn the Nachtfee frame on its side as to get access to otherwise 'impossible places'. During the same opportunity Dick supported with removing the 'order' or command scale which showed strong signs of deterioration. This wasn't as simple as expected as some screw nuts were rusty and very difficult to access. But finally we removed the integral 'order' module . Having now separated the 'order' scale from the rest of the Nachtfee apparatus, the degree of deteriorating is clearly visible.
2011 13 December: I took the quartz related modules to our MLK Lab., because we are equipped there for these kinds of investigations and experiments. My aim first was getting the quartz stage operational, be it partially, as my normal approach always is, to get something working, from where it is easier getting grip on the circuit under consideration. The next photo is giving an idea how the various investigations were commenced. When one is investigating something which function as well as interactions is not entirely understood, it does make sense getting in this puzzle as much as possible bit and pieces together. Finally it becomes clear what it all is about. Sometimes not yet even this fully. As we will learn the high voltage I choose, was far too low; but how should I know? In 99% of the electronic circuitries existing a HT of say 275 volt is normal. It should be, however, 450 V. Owing to this huge difference, quite some circuit couldn't operate appropriately. My problem was, that I used for practical reasons the existing voltage dividers, as I fed the entre HT just at the point coming from the normal HT rectifiers. The voltage-dividers lowered the operational voltages fed onto the various stages so that finally much too low voltages remained.
2011 12 December: The schematic is drawn from the the double sized module. Its real purpose was not yet understood, as I was not aware of the implications of the drawn circuits! This was partly due to the fact that the supplied HT (250 V) was too low for its proper operation. Don't worry, we will also clear this mystery!
2011 8 December: The yet called: double sized module is first modified by bridging their capacitors.
2011 7 December: I decided that time has come to connect the Nachtfee system onto the 220 V ac mains (please scroll down this link). The two rectifiers were not yet in place, thus we most likely only have to deal with the filament supply. Which estimation was correct. About the same time, I have started with bridging all the roll-capacitors by good quality Philips types of the 1960s. The only ones kept in operations were the Sikotrop types, which are hermetically sealed-off from environment. Even after 70 years these are according specs!!
2011 30 November: Nachtfee Survey page 3 is setup, which succeeds survey page 2. My first aim was to find out what valve types might fit into the empty valve sockets. It was found that the most likely option is either an EL11 or a EL12. Regarding the size of the transformers as well as the wattage of the resistors, my guess was an EL11. Which choice proved to be correct.
2011 23 November: With the help of a friend I was able to separate a mysterious central module carrying the 10 + double size modules. What is inside? My expectation was some filters or that like. We will face, however, that time and again things are totally different from what they in first instance seemingly look like. My interest was pointing what is inside this black module? For it opening is the only option. It was soon found that no one before me had ever looked inside it, after it had been sealed off in say 1944. After having removed the second plate, which was isolated by means of a bright white glas-fiber-plate, my breathing stopped virtually!! 10 piezo-electric quartz crystals were mounted inside a thermostatic oven. Apparently to be kept at 60 ° C. The centre frequency is around 15000 Hz each one separated from one another by 60 Hz up and down. Why? In my say 50 years of experience with German electronics, I have never seen such a quartz crystal type, never! From our 2000 Kootwijk event I knew already that these are most likely so-called X-plane vibrators, which vibrate in a longitudinal mode. Quite often used in the early days of quartz technology. Their motion can be extremely self-destructing as, when oscillations is not kept under control, being 1 -3 or even more mm!! We will see later, that this aspect is not widely appreciated. But final measurements on the purpose of the potentiometer build-in the quartz modules is just having this purpose.
2011 12 November: Alfred Breur was so kind to remove some of the Nachtfee cover plates, as well as the one carrying the numbers 1 - 10 However still unaware where these ten modules and the double sized are being meant for.
2011 12 November: After extremely tough negotiations and breakdowns arrived finally a crate of just over 95 kg. Which was very kindly collected by Paul and Marc (both Board Members of our Foundation). After having removed the wooden crate-plates the curious apparatus became visible . From now onwards a long survey or project started. It was soon decided to make it workable again, maybe temporarily, but at least for the time being. Although, in such a way that at all times it could be converted again into its original shape.
2009 Early September, Phil Judkins came over to rehears our dual presentation for the DEHS AS09. Among a bunch of NA/PRO copies was a translation of a German wartime radar periodical issued on 25 February 1945, called Radar News 19. Interesting stuff by the way; but the last illustration page gave a tremendous shock. It showed, schematically drawn, the application of the apparatus which was on EBay early 2005. What to do, after four and a half years had been passed? My only thought was adding a separate page called: Wanted with a brief description and photo of the 2005 EBay apparatus (please notice that this page has been changed a bit). Within, say, three weeks I received an e-mail message from the States, with the message: I have it. All sounds simple from now, but it definitely wasn't! I trust, that it is easier obtaining Obama's notebook, than it was getting a deal and its arrival in the Klooster on 12 November 2011. Almost exactly two years had been passed. With a lot of blood sweat and tears I can tell you; only with the great support of my old Hellschreiber-friend Brian it finally was settled.
2005 Willem Klein who is guiding groups around the former airfield Deelen in the Netherlands, sent me an e-mail in which asked me whether I knew what is on the photo? It appeared that this device was currently on sale on EBay. I followed the link he attached onto his e-mail, and found some, for me, entirely strange apparatus. I contacted some fellow collectors and got negative results. The story was almost forgotten, until my friend Phil Judkins came over early September 2009. Please follow from there the story. I the beginning of 2005 it was on sale at an auction in Cleveland. Apparently an auction of all sorts of military stuff, but it wasn't a purely military one. One sale was also military gear from Britain as well as Japan. The buyer was likely not very satisfied with it, as he puts it on EBay where it was Willem Klein who brought it to my attention soon.
1966 Trenkle published for the first time on Nachtfee in a DGON (DEGON) publication: "Die deutschen Funk-Navigations- und Funk-Führungsverfahren bis 1945, He is apparently not well informed. Most what he knew was, I guess, likely supplied onto him by R.V. Jones personally; but he was untitled to share this source of information for quite a while. This restriction may have been lifted after British confidential materials were been made public after the second half of the 1970s. However, he may have quoted T. von Hauteville that 5 Nachtfee (ground?) apparatus may have been hand manufactured. How many aircraft sets have been produced may likely remain open?
1945/46 Our Nachtfee apparatus, maybe V-5 = prototype 5, being shipped to the US. Where it got: CT3379. My guess: Captured Technology together with a running-number. It is likely that it had been brought to the region of Dayton (OH). It is also likely, that they did little investigation as, for instance, the quartz oven was never touched (seals unbroken).
1945 The British translation of a GAF radar magazine: Funkmessnachrichten No. 19 issued on 25 February 1945 saw daylight. It is called: Radar News 19 . Also a series of what became known as Felkin Reports saw daylight (a series of transcripts is accessible on this webpage. Again, kept under British Secret Acts, until this ban was lifted after say 1980. Please notice, that these reports rely mainly on PoW interrogations, with all the second or third hand information, sometimes deliberately faulty. Some of it, can be corrected by our recent findings.
1944 First proof of the tactical application of Nachtfee, where GAF Pathfinder aircraft had been guided over Britain. Reported by R.V. Jones' Office A.D.I. (Sc) Report 101 followed by a Felkin Report. A second Jones report saw daylight on 11 April 1944. In the Blohm & Voss project to P194, they mention: the the Sachbearbeiter (referent) is: Fl.-Obering. Beck Rechlin and that Unterlagen (documentation) is handled by: Fl.-Obering. Bracke.
1943 Nachtfee likely being technically designed at Rechlin (GAF aircraft research and testing centre): Mr. T. von Hauteville is, according Fritz Trenkle, the technical developer or brains, although, a Blohm and Voss project data list on the fighter P194 suggest that someone else is the expert on Nachtfee. Fritz Trenkle also mentioned that Mr T. von Hauteville created the Y-system. Which was first used against Britain late 1940 and 1941; this was after say early 1943 converted into Y-Kampf (pages 12-16). Where distance as well as direction against a known station was measured, without interrupting aircraft-to-ground communications. When the flying altitude was provided the pilot was informed rather accurately what his bearing is. This provided his position against the Y-Station. In the book: Die deutsche Luftfahrt Flugerprobungsstelle bis 1945 is T. von Hauteville for Head of Section E4 (Rechlin) being: Dipl.-ing and on a second occasion Fl.-Oberstabsing. Also is a new finding in a British report, where they refer to a Stabsingenieur (Fl-Stabsing.) Benes (May have been spelled incorrectly).
By: Arthur O. Bauer