About the Breslau Störsender

a moonshine like jammer

Status: 9 December 2013

Reshuffling my desk I came across of an e-mail conversation between Phil Judkins, John Stubbington and me of Autumn 2010, which reflects a discussion and my response on to it. Rereading brought up the idea that the brief content of this e-mail might be worth to be put on the web. As in literature there is hardly a mention to the device which played a role during the Channel Dash of 11./12.February 1942; the latter carrying the German code-name 'Unternehmen Cerberus' (for the Navy (KM) and Donnerkeil for the GAF). It was a great success and the Germans passed through the straight of Dover and brought their ships Scharnhorst - Gneisenau and Prinz Eugen back home. For Britain this was a very great disaster. The Germans manoeuvred straight under their very nose of both the Royal Navy and the Coastal Command and brought their ships home with relatively little damage. This time 'NIX' Bletchley Park reading everything. It is apparent, that when likely Hitler was involved in some secret actions, like this one but also the 'Ardennes Offensive' from 16 December 1944, that Allied intelligence was completely kept in darkness. The main clue was: absolute radio- and information silence in respect to the coming crucial operations. A downside, being that some were not sufficiently informed what they had to do at crucial moments; for safely reasons the circle of those informed was kept restricted as possible.

This event was the first time in modern military history that at a great scale 'Electronic Warfare' became crucial. Since, it is one of the most important aspects of warfare.

This event has been described extensively, but the application of the spoofing Breslau transmissions is not.

Please read also: Unternehmen Donnerkeil

My explications must be seen in the context of discussions between friends.

Let us therefore follow the line of my e-mail of 16 October 2010

Trenkle passes not too much information on it. We know who manufactured  G-P (Garmisch-Partenkirchen Gerät) and that it was a cooperation between Dr. Scholz’s team and the Hagenuk Company in Kiel. I have to dig into historical sources as to find out where G-P had been employed as well. 

In Trenkle’s booklet on German jamming techniques he mentioned on page 113 that they eventually built 12 G-P systems.

A pro pos, I must say that this volume is chaotic, as on various places he is dealing with the same matter. This is typically an example of a volume that had been rushed through publication. On page 108 Dr. Kroebel and on page 113 it is being spelled Dr. Kröbel, However, both writing is correct though, not uniform. He also deals with it on page 116/117/118

In the late 1980s he severely suffered from Parkinson disease which hampered sometimes his clear thinking. This might likely have been started earlier.

Nevertheless, according Trenkle it was Dr. Straimer of HWA (Heeres Waffenamt) which is the Army procurement organisation who designed some of the Breslau jammers. Why the army became involved I don’t know. The first, I guess, experimental sets were built in the winter of 1940/41.

First radar jammers on the German side, whose signal was also synchronized by means of British radar signals was type Breslau I/II which had been made by Fa (Company). Dr. Ristow, design apparently by DVG (Deutsche Versuchsgesellschaft?) Interesting might be, that the Breslau jammers were not simply a straight forward signal jammer, but also a spoofing system.

When searching in Trenkle’s 1960s publications, I found a photo of an early Jagdschloss antenna, where he has put: “Heidelberg?” He may then not have known much about it (yet).

The DEGON published in 1966 “Deutsche Ortungs- u. Navigationsanlagen (Land und See 1935 – 1945)“ Bestell-Nr. 1038

Not always very accurate as Trenkle once told me, because some information was yet lacking. But it shows sometimes interesting details.

According this publication:  S604/1 was Breslau 1 shared DVG/Ristow design; S604/2 Ristow design.

Breslau 1 for 22-28 MHz power 1 kW; Breslau 2 for 40-50 MHz power 1 kW.

Attached as curiosity, you find a photo of the Breslau 1 installation which you never before might have seen. The module up on the left has some strange distortions, which after consideration is a typical Trenkle made correction (retouch) as is also visible at the line drawn around the crt screen.

The Breslau jammer type I or II installation

Please notice the five units, each one constituting a transmitter which retransmitted the received enemy radar signal in each transmitter module being delayed in time. Causing, a chain of five spoofing radar signals.

We may regard the Garmisch-Partenkirchen airborne transmitter being based on the same system philosophy, like was the British Moonshine jammer.