[ARC5] German FuG 10 "Kurz" 3-6 MC Receiver IF

Sat Mar 16 12:22:43 EDT 2024

My German Radio project is a 1944 Torn Fu.d2.  The big hold up is the metal battery pack for the radio. I’m looking for a tin knocker that can reproduce the box out of aluminum ( not using the thin sheet aluminum with the wood core that is original ). As soon as I find a tin knocker who wouldn’t charge me my first born son ( wait a minute, let me think about that for a minute….. nah, mom would be pissed ), we’d really be off the the races on this project. 

73
Mark D. 
WW2RDO

“In matters of style, float with the current. In matters of Principle, stand like a rock. “.   -   Thomas Jefferson 

Sent from my iPhone

On Mar 16, 2024, at 9:40 AM, David Stinson <arc5 at ix.netcom.com> wrote:

Good Morning.
Re: German FuG 10 "EK" (Shortwave) aircraft receiver.

https://photos.app.goo.gl/4Vh84wn7ktNmy2MV8
https://photos.app.goo.gl/4Vh84wn7ktNmy2MV8

I am grateful for the excellent help our excellent
group has provided concerning this radio.
I get 20-30 mins to work with this set every
couple of days, but with the group's help
this time has been productive. That the Germans,
ever thoughtful in their designs, marked most of
the components with their part numbers, has made
trouble-shooting easier.

https://photos.app.goo.gl/nmoyo6m61nHovaua9

It appears that there were several "builds" of this set,
some of them differing significantly from others.
For example- an early set was wired for 12V heaters,
while this one is wired for 24V.
The early model had a two-valve audio output stage,
while this 1941 model has one triode-connected output.
The 10-pin "testing" connector on the front is wired
differently from any of those in the documents.
There are other significant differences among the three
sets of documentation I have gratefully received.

My concern at the moment is the correct IF frequency
for this 1941 model.  Within the documents I have,
it has been variously reported as 1875 KC, 1600 KC|
and, on sweeping to determine IF, I found the BFO
(previously diddled and repaired) at 1495 KC.
I have not touched the IF adjustment.

The BFO would not oscillate at first.  I found the screen
of the valve at 12VDC, and the plate at around 150V.
Examined the screen bypass cap and found it good.
The screen dropping resistor was rated at 1 MegaOhm and
had drifted to 1.5 Meg.  I temporarily paralleled a resistor
to bring the screen to 28V, which restored reliable oscillation.
However, this "fudged" voltage is not likely to be the
"spec" voltage, so it will change the oscillation range
of the BFO.

Does anyone know for sure the IF frequency of this model?