Introduction

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One of my first pieces of research was into an agent-dropping operation by I./KG 200. Years later I learned that the pilot concerned had served with 6.(F)/123, which had absorbed aircraft and personnel from 4./FAGr. 5 which had in turn been formed from Horch- und Störstaffel 2, itself the successor to Sonderkommando Rastedter which was a descendant of Kommando Koch. So in effect this has all been a matter of following a trail back to what (I think at the moment) may be its starting point.

As early as February 1942, the Luftwaffe had employed jamming aircraft in support of Cerberus the move of two battleships and a heavy cruiser from Brest, up the English Channel to home waters. According to postwar interrogation of Dr. Ing. Werner Scholz, a civilian scientist with the German postal service, the first Luftwaffe airborne jammer, Caruso, was deployed to the Mediterranean in 1943 to block communication between RAF night fighters and their controllers. This device dated back to 1941 and initially proved underpowered but once boosted it was used for barrage jamming. It was however so cumbersome that only one could be carried per aircraft so no single machine could cover the whole of the relevant waveband. In addition, efforts had been made to jam height-finding sets on Malta, and tests undertaken at the Köthen research establishment with captured British ASV (Air to Surface Vessel) radars. Scholz related that a Sonderkommando Koch had been formed in the summer of 1942 and based at Athens-Kalamaki, aiming to jam ASV with the Kobold (goblin) transmitter, on the 160–200 mHz (1.5–1.9 metres) waveband. The unit was led by Hptm. (later Maj.) Adolf Koch of Köthen.

NOTES: (1) Koch had come to British attention as early as October 1940 (in connection with the subordination of 6./Signals Experimental Company to Luftflotte 3) then again in March 1941 (through a message advising that he had resumed command of the II. Abteilung, Signals Experimental Regiment, Köthen).,

(2) The British had been considering jamming air-ground VHF since 1941 as well. In January of that year two medical researchers, Mark Clement and Philip Cleary, approached the Air Ministry offering to demonstrate a “new apparatus (secret weapon) for jamming enemy aircraft radio messages”. They noted that:

At the present time enemy aircraft are able to receive and to give messages in the course of their attacks on this country.The object of this secret weapon is to render such communications impossible in future …

By 21 February however Clement and Cleary had been bombed out of their workshop, losing both the experimental model and their equipment, although they and the blueprint survived. Their request to the Ministry of Aircraft Production for £300 (about £15,000 at 2019 values) to construct a higher-powered prototype was turned down as “the matter is not of sufficient importance to warrant the expenditure of time and material”. Six months later however, the Director of Communications Development was writing to the Telecommunications Research Establishment:

… to confirm that a requirement exists for an airborne transmitter which will provide effective jamming of the VHF fighter band. It is understood that considerable work has already been done in this connection …

(3) A potential source of confusion for researchers is the presence of another and quite distinct Sonderkommando Koch in the North African theatre during the summer of 1942. A detachment of “smoke troops” (apparently a Nebelwerfer mortar unit) led by a Hptm. Koch, it had left Benghazi on 26 June at a strength of three officers and 104 other ranks.

 

Prelude

Aircraft were assigned to Luftwaffe signals units early in the North African campaign. In October 1941, two Fi 156 Trop. (W.Nr. 5372 and 5376) had been assigned to LN-Abteilung (Air Signals Battalion) Afrika but their arrival appears to have been delayed. In March 1942 there was a clear sign that electronic intelligence flights were planned: two more Fi 156, intended to undertake direction-finding, arrived. They were however without their crews who were thought to have been lost when the ammunition ship SS Cuma was bombed in Palermo harbour on 3 March. Back in Europe a heavy telephone construction squad “for continuing experiments with Fieseler Storch” was sent to Köthen. Two months later, the LN-Versuchsregiment (Trials Regiment) was transferring yet another two Storch to the above-mentioned battalion; these machines being fitted with “FuG X” (presumably the FuG 10 transceiver). A total of five Fi 156 was thought to have been on hand by the end of May.

On 23 April the Luftwaffe’s Director of Signals had contacted Ob. Süd about the »WIM« installation planned for Crete. This must be on the highest possible ground, with no rising land behind it; an emergency power supply would be required as no mains current was available. The site would need two duty rooms and an annexe to accommodate 15 men, as well as two tents and a permanent base for a direction-finding mast. On 18 May Fliegerkorps X’s Senior Signals Officer asked the Luftwaffe signals branch what the weight and dimensions of the equipment allotted for this by »RPZ« would be. In time it would become apparent to the Allies that »WIM« denoted signals monitoring and jamming.

Later in the war the German “Rotterdam Working Group” set down what was known at this stage:

By mid-1942 the observations made thus far presented a comprehensive picture of the enemy’s radar systems. At a time when aircraft with radar sets first became dangerous to the German U-boats, both the observation receiver and a directory of the enemy devices in service and their wavelengths were available.

… the technical surveillance service on the Channel coast had been interrupted by the monitoring in the Mediterranean …

continued on next page…

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Kochtag

TIMELINE

 

21 June

Tobruk surrenders to Axis forces, Eighth Army retreats to El Alamein/ Alam Halfa line.

25–29 June

Battle of Mersa Matruh.

30 June

Axis forces reach El Daba.

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