FuBl 3F


Page initiated on 5 May 2017

Although, this project started on already January 2017


On 19/20 October 2017


+ C +D + K + L + M

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This project should be regarded Hans’ project



Hans Goulooze was concentrating first on making the remote control to the Ebl 3F operational

This didn't commenced well in first instance, because the parts obtained via Ebay weren't of sound quality.



It soon proved that quite some was lacking, such a the driving motor within the right-hand section of our Ebl 3F


On the right-hand side the FBG2 rmote control unit, which includes an indication that inside the Ebl 3F the correct setting being accomplished.



On 20 April 2017

Hans Goulooze was busy with getting sufficient sensitive reception.


With some care the EBL 3F started to operate, albeit, in the beginning quite some work laid ahead

YouTube films demonstrating the FBG 2 remote control interacting with the Ebl 3F mechanism

Film 0233

Film 0234

Film 0235

Film 0236

Film 0237   

Film 0238



On 8/10 June 2017


Hans Goulooze has made good progress in getting the combined EBL3F and EBL2 operational again.

The previous week he encountered all sorts of nuisances, but didn't yet grasped what the faults caused.



On the left-hand side the EBL 3F receiver, next to it the EBL 2 module, with removed screening plates. In the centre Hans Goulooze holds an open AFN 1 indicator in his hands

For this occasion we operate an AFN1 because this sample is at hand including cable connector as well as neon indicator lamp.



Getting a better vision on what Hans is actually doing

Please notice the device with connecting-pin-holes. It is a very versatile device by which means one can measure signals inside a cable interconnection.

Its type is P Mst1 (Prüfmeßstecker Typ 1)



The centre connector-section is feeding the connector pins 1 : 1 onto the according test (Büchsen) connections of the remote P Mst 1 module

The pin and cable numbers are maintained equal. Albeit, that in one occasion a resistor being implemented; its purpose is to allow measuring across the resistor as to get the actual current flowing.



For this occasion the SMS signal generator being used as to supply the modulated carrier at 32.0000 MHz, which equals EBL 3F channel number 21

As to get 1150 Hz necessary for simulating the long-distance landing-beacon-signal an external tone generator being used.



It finally was discovered that an incorrect contact number inside the EBL 2 connector had been once made

This easily can happen as all cables are of equal yellow colour.



However, the fault was determined and it all started to operate as may be expected in this experimental stage

The small circuit between the coaxial antenna input and the coaxial cable interconnecting the SMS has been implemented as to prevent damaging of the SMS signal-attenuator.


YouTube films:

Film 0244

Film 0245

Film 0246




To be continued on 15/22+26 June 2017


Hans Goulooze continued with considering the means with which the EBL2 module can be interconnected onto the dipole matching box DAG1* ; the way this once had been done was accomplished by means of so-called twin-ax of bi-ax cable.

* DAG 1 stood for: Dipolanschlussgerät (type number) 1. It has to be noticed, that we have to make a - replica like - DAG device, albeit electrically of equal properties.

The EBL2 and DAG 1 combination being meant for receiving the 38 MHz landing beacon signals (700 Hz and 1700? Hz). Please consider in the next drawing the VEZ and HEZ signals. Such kind of beacon signals crossed the virtual landing path, informing the pilot that first he is 1000 m ahead of the the landing strip and with HEZ that only 300 m being left.



This drawing originates from my CHiDE presentation on Navigational Aids, of, when I remember well, 1997

It shows what the "Funk-Blind-Landefunkfeur" is about.

Before the war the so-called Lorenz Blind-Landing-System was used nearly everywhere in the civilised world. 

Please notice, that when the pilot reaches the main warning signal 300 m in front of the landing strip his altitude (h) should have been reduced to 30 m above ground level.



Although, not yet dealt with in great detail, it is worth noticing what the system was about; because sooner or later we have to deal with its aspects


An aircraft approaching from distance will likely receive the airport beacon signal (some even from > 100 km), telling the pilot that he is whether, just on the exact approaching path - hearing in his earphones an uninterrupted tone of 1150 Hz; or right of the virtual path receiving dashes and left of it getting 1150 Hz dots in his earphones.

The trick was - that when both alternating antenna patterns coincide in its virtual centre, that the pilot receives both complementary signals which is then recognised as a constant tone. The course meter (AFN 1 or AFN 2) pointing  (staying) in the centre between L and R.  In case the aircraft tends to become off the virtual navigational track the signal is becoming modulated with dots or dashes; the way it sounds telling him whether being off to the left or right hand path side.



I bore in mind that about thirty years ago I obtained a bunch of German antenna cables. In our cable storage we indeed found where looking for, a special brown cable type. Its brown colour indicated that its application once was designated for the purposes where frequent cable-bending occurs.

For example, the early Würzburg type fit with its strange, soon obsolete, IFF facility. The two antenna-dipoles were mounted inside the parabolic mirror; left and right of the antenna arrangement. When the Würzburg antenna-mirror changed elevation  cables need to cope with (some) bending.  



Preparing the cable is more or less done in the usual manner

The main dielectric is most likely of the low-loss Opanol type, well suitable for its purpose. It isn't really solid but it behaves like foam. Foam implies air-inclusions, which is increasing the so-called velocity-factor of the RF cable parameters; I guess ours ≥ 0.7  and also improving cable flexibility. Regular coaxial cables have a velocities of, say, 0.66

A brief tour through some aspects of speed of light (c) versus the signal velocity in systems consisting of dielectrics

More technical approach: v/c wave velocity through a medium versus speed of light;  and v = 1/ε 

However, copper antenna-wires hanging in free air are still being considered having 5 % velocity loss. An example, designing a dipole antenna for the 20 m amateur band (14 MHz); its λ = 21.428 m.

This antenna should therefore have a mechanical dipole length 21.428 : 2= 10.714 m

Considering 5% wire velocity loss is reducing the antenna wire length to: 10.714 - 0.5357 = 10.178 m (considering that the central feeding points are very near to one another).

Let us now consider we would like to use our brown cable as to constitute a ¼ λ stub. I considered our cable type is having a v = 0.7. The length of our imaginary stub would become then: (21.428 : 4) ∙ 0.7 = 3.749 m.

The consequences of all this, is, that signals travelling in a cable or transmission system is doing so never with the speed of light - but with a considerable lower velocity. The less dielectric constant (ε) involved the more a transmission line reaches the speed of light; but will never attain it. How light behaves in fibre optics I don't know, but it is most likely that these also have to deal with velocity reduction owing to dielectrics.



Maybe recognisable: around the two conductors being wounded a 'silver like' tape (the phenomenon is not well visible on our photos)

This silver-like shining isn't like that but might originate from 'surface light refraction', as this tape proves to be fully transparent.



Maybe this photo helps you to understand what it all is about

It is astonishing that this cable remains over more than 70 rather flexible. German coaxial or related cables where of a rather high quality standard. Maybe, rather expensive too, as, for example, the copper screening breath is rather heavy; hence, production consuming quite some Cu quantities.

It has to be noticed though, that in those days they may not have operated this more expensive (brown) cable type between the EBL 2 and the AAG1, but the less flexible 'blue colour' cable type. However, we only possess of it a short sample of not yet, say, 70 cm length; hence, for our display purpose too short.

I suppose: that the application of tape surrounding both copper conductors is to create flexibility between the foam-like cable dielectric and the (two) cable conductors.



Maybe this presentation is more recognisable



Just before soldering

Time and again it proves, that decisions made some 30 to 40 years ago are later often decisive for (new) projects. Gathering bits and piece, where the direct purpose wasn't always understood, but the 'trust' that it might later fulfils a purpose.



Hans Goulooze has started considering as to how it later can be mounted on display, of course, fitting within the designated display space



Viewing it slightly different


Hans Goulooze's first idea is constructing a light wooden frame so that we can learn how it all fits together well; with the aim later creating metal mountings. 



The space where the FuBL consisting of an EBl3-F and EBl2 + U8 is planned to be positioned is just between the border of the glass-window and the (white) wall below the two blue-window- frames

It is evident that space is quite restricted, but with some care it should be makeable.

The 'Funktisch' has been pulled towards us, as to show what it actually is about; but regularly it is to be noticed through the glass-window.



The FBG2 (the device with the number scale) is to be mounted within the previous shown genuine 'Funktisch' left of the Morse-key; this was its wartime placed within the Siebel type 204 aircraft

This aircraft type was used for carrying passengers on quite long distances (I guess up to 8, excluding the crew); and it flew still in post war days, in several countries; I know in Holland and Switzerland, but likely in more countries.  

The FBG2 is the electrical remote-control of the blind-landing receiver type EBL 3-F.


For those interested in the FuBL system its genuine manual might be helpful. Also increasing understanding of what we actually are doing.  


D.(Luft) T.4058: Funklandegerät Fu Bl 2, Geräte Handbuch Februar 1943 (please notice that its data content surpasses 12 MB)  This data has kindly been made available in digital format with courtesy of Ernst Wagner, Kemnath, Germany.



On 8 September 2017

Summertime has apparently passed, albeit not yet according the regular calendar.


In the meantime Hans Goulooze has done a superb job, he created a wonderful wooden frame which just fits within the board-display-space available.

Please notice first the second foregoing photo.



Our consideration first was how to integrate the FuBl 3F - Ebl2 installation in to the already existing display space

The locks (Schlösser) should arrive, Deo volente, Saturday 16th, this month; Hans is desperately waiting for them.



Invisible on the rear side a common 'ground rail' being implemented (please notice the next photo the Al strip at the rear side of the wooden panel



 Hans has used cable colours as far as possible according the genuine cable data, but where we couldn't match to this, he used other colours but consequently

He also has drawn a wonderful sound cable-plan accompanied with full details.

Please notice, just visible the Al guarding (ground) rail.

The switch-handle is for selecting the two possible power modes.



Hans provided, a facility with which we have a choice between operating the alternator U 8 (Umformer type 8) or allowing operating it via regular external power supplies. These supplies are to be interconnected onto the terminals: BA (24 V) and A (260 V)



The coloured wires are well visible

We are happy that we just have enough complete sets of plugs and according cable connectors; as these nowadays are most difficult to find.



These quite odd connector types genuinely originate from pre-war days; but have been used as long as design originated from pre-war or very early war period

It should be noticed that Blind-landing gear existed already since the later 1930s, and accordingly systems were implemented in GAF service.

However, technology improved and systems have been modified step-for-step. Therefore it was quite logic that when implementing single modules into an existing rig that, for simplicity, the original connectors types were still utilised.



On 15 September 2017

Hans Goulooze continued yesterday with 'his' FuBl2 - EBl3F project.



Hans' wooden - combined EBl 2 - EBl3F - being placed, temporarily, where it ultimately should be brought on display

When brought to a conclusion it should: constituting an integral part of our aircraft wireless rig. 



Viewing for a bit different perspective

The remote control at the glass-window is finally to be implemented in the genuine Siebel 204 wireless/navigation table.

However, we encountered a problem concerning the output signal of the EBl.2 module; the signal often drops 10 or more dbs.



For this reason the EBl 2 module had to be taken out-of the wooden frame

Please notice that the so-called locks should, Deo volente, be collected on the 16th in Driebergen.


Hans's first action was to look for supply voltage faults

Knocking at various points on the EBl 2 chassis resulted in a wild response on the oscilloscope. Those familiar with those kinds of annoying faults, will not wonder that after all plates had been removed the failures couldn't be reproduced!


we also know - that this doesn't mean that the faults have been solved!



My proposal: let us wait until the next week

Thinking the encountered effects over again, it might be caused somewhere within the VEZ or HEZ signal filters. The latter consisting of an 1150 Hz modulated tone for this occasion.

Albeit it, that we haven't yet implemented the landing-beacon functions (@ 38 MHz), but instead of modulating the EBl3F signal with 1150 Hz. Because both systems join a common audio channel.



On 21/22 September 2017

We just received another Ebl 2 module: 



After having demounted the front-cover-panel it was discovered that this device is in a rather sound shape and most likely - inside - untouched

We have been informed before we obtained it, that the so-called Kabelschänze being cut off, but  substitutes are accompanied.



Photographed from a different perspective

It is noticed why the cables had been cut, as the cable insulation deteriorated; considering the forgoing photos this module might originate from the end of the 1930s or early 1940s. Whether this is the reason for insulation deterioration I cannot say. My suggestion to Hans Goulooze: let us operate it first in this genuine fashion.



 What might occur is that some capacitors will fail in due course

On the far left-hand side the notice the 38 MHz VHF front-end section.



Schloss type Fl 28251 (Fl was a GAF part designation); 'opened' 




Aren't these wonderful replica's?



He did a really wonderful job!



Preliminary checking how the Schlösser should be mounted



This lock had to turned as to ease lock-access



On 18 October 2017

Some progress has been made with respect to replacing the wiring of the two EBl 2 connection cables; one for the supply the second one for interconnecting signal cabling.



It is well visible that Hans does his work meticulously! 



Viewing it from a slightly different perspective




On 19/20 October 2017


Hans Goulooze has accomplished renewing the so-called Kabelschwänze (the cables between the EBl 2 module onto the connectors.



After some queries, likely caused due to confusion, all started to respond appropriately 



Viewing at it slightly from a different perspective


But Hans has built also a beautiful substitute antenna, which normally was built just inside the belly of the fuselage; as not to much causing drag, but still receiving the two beacon signals at 38 MHz un hampered.

Isn't it really wonderful?


It electrically should be fully operational; as the measures are copied from the genuine manual

Even the height above the metal plain is kept according the data in the manual.


We possess genuine German twinax-cable (bi-ax) and Hans has already calculated the values of the antenna matching substitute module. Both - his calculations - as well as the data given in the manual are about equal.

Our idea is, to build the matching unit into a box that should be mounted near to the antenna feeding point, but at the rear side of his antenna rig. Albeit, such that optimal tuning can be accomplished conveniently.



In my vision this is the optimal place to mount it at the wall (just up of the central heating tubes)

We have also discussed it being mounted on the sealing, but in my perception people have inconveniently looking straight upwards.



Looking again at this beautifully made construction It looks like that this FuBl 2 test set isn't operational, but it fully is.



It has been opened because the antenna current meter isn't responding, but likely the meter or the thermocouple is defect

This test set generates most relevant landing beacon signals including the VEZ and HEZ signals; please notice the yellow text "Modulation".   


To be continued in due course



By Arthur O. Bauer