Countermeasures against Allied jamming techniques (W-R)

[beaviso]

With introduction of jamming techniques, incl. chaff (alu-foil stripes), the Germans started to improve their radars by adding-on some "bits and pieces" which helped to distinguish airborne targets despite the difficulties. I came across the following systems:
- GEMA add-on to W-R
- Wuerzlaus
- Nuernburg
- K-Laus

While Wuerzlaus and Nuernburg have both been satisfactorily described, the GEMA-Zusatz and K-Laus are more mysterious to me. Can anybody please give some insight into it?

For example, is this possible, looking at the picture of a W-R, to say what add-on it was equipped with? What was the purpose of small rod-antennas at the top of the W-R reflector?

More on this subject:
http://www.vectorsite.net/ttwiz9.html#m2


Below you can see a picture from "Waffen-Arsenal" showing a small Wuerzburg operator wearing headphones, which were an element of the Nuernburg system.

I also show a piece of a blown-up W-R, found with metal detector at one of the Polish sites. You may note the diagramme includes "Kopfhoerer" - the headphones.
Does this mean that this particular W-R might have been equipped with some additional "de-lousing" system?


brgds / mfG
Michal

[SES (†)]

Hi Michal,
The small antenna seen on top of some W-R was the "Kuh" (IFF) antenna. I'll be back with more comments on the anti-jamming circuits. Please note that the systems you mention were internal "add-ons"/modifications and mainly based on the MTI technique. Leif ought to be able to give a short easily comprehended lecture on the MTI
The system depicted on your diagram was based on the ability to detect the modulation of the reflected radar signal by the propellers of the allied aircraft. If the echo was from chaff there was no modulation. So with this mod. the operator observed the reflected signal and "listened" to it at the same time.
bregds
SES

[beaviso]

The small antenna seen on top of some W-R was the "Kuh" (IFF) antenna. I'll be back with more comments on the anti-jamming circuits.

Thank you

Please note that the systems you mention were internal "add-ons"/modifications and mainly based on the MTI technique. Leif ought to be able to give a short easily comprehended lecture on the MTI

That's right - it was the most straightforward way - to differentiate targets changing their azimuth and distance from somehow "stationary" chaff by implementing ideas of Doppler effect.
You SES probably know - from the cold war era - the manoeuvres to avoid our Floggers' and Fulcrums' Doppler radars

The system depicted on your diagram was based on the ability to detect the modulation of the reflected radar signal by the propellers of the allied aircraft. If the echo was from chaff there was no modulation. So with this mod. the operator observed the reflected signal and "listened" to it at the same time.

That's exactly the basis of the Nuernburg system.
What I am wondering is - were the headphones a standard equipment of every W-R cabin (for communication purpose), or did their presence was straightly conjuncted only to the Nuernburg add-on?


best regards
Michal

[SES (†)]

Hi,
Yes I do remember
Since the W-R operators in the cabin were in constant telephone contact with the Seeburg Tisch operators, I think that they wore headphones before the advent of Nüremberg.
Attached is a little additional info on anti-window circuits; F-Trenkle "Funkstör".
bregds
SES

[SES (†)]

For those of you who really want to get into technicalities I can highly recommend this excellent site:
http://cdv-and-t.org/

bregds
SES