Interception receiver type b
Serial number 8678/41 (year 1941)
It is rather curious that so far there is no original FuHEb apparatus manual around
Some story is being told that someone has one, but is not cooperative and is rejecting to share his possession with the collector community. Combining the information around, which concerns the simple operational manual D.1053/5 the schematics must be part of manual number D.1053/1. There existed a system in which D. xxx/1 is the main technical manual and D. xxx/5 ( /5 = Merkblatt) is the one that provides operational instruction though, leaving out technical aspects of circuitry.
However, some information was around and we have some in our archives. I think I once got a copy on behalf of late Dr. Heinz Lissok from Brussels. The occasion was that I had to overhaul his malfunctioning FuHEb. The problem was, as far as I can recollect from memory, that the widely employed blocking capacitors were all having intolerable leakage resistances*. As the FuHEb uses rather high impedance circuits, already a small amount of electrical leakage is causing serious problems. In Lissok's case I decided to leave the original ones on their place and used them as stand-off for modern type polyester type capacitors (mostly being 1 µF 150 V types). The reason for doing this is directed from the necessity of keeping historical artefacts in such a condition that after removing the added components that all is re-converted into its original state. Our FuHEb receiver was produced in 1941, thus in a time where quality was written 'in capitals'. Although, I haven't recently checked it - I believe that the receiver is still working fine. As in those days the high quality capacitor blocks where of the highest quality order. * This was due to 1943/44 nuisance, as the Germans left out for rational concerns the more expensive hermetically sealed-off block-capacitor types. They adopted the types usually employed in Allied apparatus instead. However, now facing the same down-side as is occurring so often with Allied wartime components - malfunctioning owing to hygroscopic defects in dielectrics!
I have to apologize for the sometimes poor quality of the hand written technical drawings. Which might be copies of copies, which were actually private sketches. I guess that these have been made about 1962. However, they proof that the one who made them must have very well understood the entire receiver concept. It is clear that the FuHEb most likely was the most advanced type of the range of FuHE a-f - interception receiver. It was equipped with two quartz-filters, of which one was tuneable. It possessed three IF stages and even a separate AVC (AGC) amplifier stage. And a double quartz BFO one for USB and one for LSB.
Please watch for some brief technical details:
Exhibits registration to: FuHE b
FuHEb schematic (I guess derived from the manual)*
FuHEb part schematics (3 x A4) and component list (Stückliste)(some extra information was added by AOB about two decades ago)
FuHEb repair information from I guess about 1962
* Please notice that the schematic is an A1 size object. However, Adobe-Reader has a provision which allows you to print what you see at your screen. Thus, try always to get an entire drawing or illustration complete at your screen. Printing will be accomplished by your actual printer-driver and its settings. Most people will have an A4 or related paper size and Adobe-Reader will cause now printing that size. It may like that all is now becoming rather miniature, but with a good printer it is very well readable. Thus, our A1 sized document is being printed in, say, A4 format or any other format you would like to adopt.
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