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On the 4th, Kesselring had been asked for his decision on a proposal to use a 20 kW transmitter in Athens to broadcast spoof messages over RAF reconnaissance frequencies during major convoy operations. A message the following day however suggested that the object might be to jam rather than mimic British traffic. The same day, Oberst Aschenbrenner had advised Kesselring:

I have received your communication about WIM operations. Apparently a false impression has been created, ground WIM stations are at the moment only in a position to receive and are already working continuously for the WIM in Kunawi [sic]. the first two ground jamming transmitters will not arrive from the factory until next week. They will be brought over by air transport. Preparations are being made to operate in Western Crete and Derna.

Those two locations, a little under 300 km apart, lay at either end of the longest open sea section of Axis convoy routes to Benghazi and Tobruk. The latter was the more important because it was nearest to forward positions and had a rail link with the front. As the RAF’s Operational Research Section appreciated:

… shipping could creep down the Greek Coast, through the Corinth Canal, down the Aegean, and so direct from Crete to Tobruk. The only part of this journey which could be easily reached by our attacks was the last stretch and this was so short that it could be covered in one night and two short daylight periods; during the latter fighter protection could be provided. On the other hand this last section of the route was not unduly far from our forward bases in the Alexandria area …

As later experience would show, the expected transmitters had between them sufficient range to interfere with ASV. over the whole Crete–Libya gap.

On 11 September, Ju 52 KA+SB (W.Nr. 7532 of LN Regt. 2) left Munich laden with additional gear and spares for WIM stations 5, 6, 7 and 9 as well as “domestic equipment of every kind for H[orch] Trupp El Daba”. Some of this material—requiring “the most careful handling”—would be unloaded in Maleme before the Junkers carried on to Derna and El Daba. The final instruction was that, “the setting up of the transmitters is to be done with all speed”, probably referring to the two Karl sets destined for WIM 7 at Derna. Next day saw an order passed to Sonderführer Mahlow, WIM 9 at Derna that Sonderführer Unger was to be sent to Crete-West to set-up a Nachtfalter installation there.

The next known operation by the Kommando came ton the 14th, one of the two aircraft involved taking off at 1545. Jamming took place from 1820–2230 and, after an intermediate landing in Heraklion, from 0100 hours. A second “RDF search and jamming” He 111 was unable to take off thanks to engine trouble. While the effectiveness of the jamming could not be established but monitoring from El Daba picked up five “ASV U-frequencies”. By 2100 four of these aircraft were “about opposite the convoy to Derna” and were heard until 0200 hours. Just before midnight one of the search aircraft, thought to be a Wellington, had reported one unknown ship and two destroyers.

Four stations were told on the 15th to prepare for a jamming operation, FRIDOLIN, within the next few days, for the protection of convoy traffic between the European mainland and Africa. This was to take the form of spoof messages, apparently with the aim of swamping the frequencies used by enemy reconnaissance aircraft and their ground controllers. Two days later, “W Leit Südost” in Athens was told to ready a 20 kW transmitter to jam on 6540 kHz and another to operate on 3460 kHz. A partial intercept on 15 September referred to the Nachtfalter equipment of WIM 1 at Noto. On the morning of the 16th, Fl.Kps. X was told that He 111 CQ+TD was leaving Berlin-Tempelhof for Kalamaki, carrying the requested radar-monitoring supplies. Feldwebel Kaltofen (presumably travelling aboard the Heinkel) would be a radio/radar operator and Fliegeringenieur Herold would repair the monitoring sets. As a WIM operator and engineer, Herold would repair “the remaining WIM apparatus” and was not permitted to go on night flights as he must remain available for work.

Over Malta in the early hours of 15 September, P/O’s Robert “Moose” Fumerton and Pat Bing of the No. 89 Squadron detachment scrambled, encountering jamming but no enemy aircraft. On the 16/17th an He 111, in the air from 2110, jammed three frequencies from 2215–2250 but broke off with technical defects and landed at 0232. The British later inferred from information given by prisoners that this may have been a sortie flown by Obltn. Schwaighart in an He 111 carrying the Protekt system (see below). He had escorted a convoy between Crete and Tobruk, jamming the ASV of approaching British aircraft and had seen their flares drop far away from the five Axis ships (a similar success was thought to have been achieved early on the 15th).

Two Wellingtons of No. 221 Sqn. reported jamming or interference on the night of 15 September. Despite “S.I. interference throughout whole operation”, Sgt. Deschamps’ crew (in BB471) picked up six blips some 60 km NNE Derna and dropped flame floats without making visual contact. Flying Officer Hancock’s aircraft (HX475/Q) found a convoy, consisting of two merchantmen of 3–4000 GRT, four escorts and “two other blips not investigated”. Dropping of flares and flame floats was “exceptionally good” despite interference on ASV. Unfortunately, one flare had hung up on its rack and the Wellington burst into flames on landing. Several of the crew were hurt but the Wireless Operator, Sergeant Ronald Wheale, died of his injuries.

A possibly related event was a “special scramble” by F/L George Coleman and his Observer P/O W.R. Beasley of 46 Sqn. in Beaufighter X7628:

2155–0025 [GMT+2] Special Scramble, Taposiris Area. No contact made, made special runs on various beams. At 10,000 ft for the duration of the flight.

Covering the MV Nerucci on the 17/18th were two Heinkels: the first started at 1615 but its equipment failed and the second machine took off at 1902 hours. From 221 Squadron that night: ”Enemy convoy found by F/O Cochrane [HX381] and Sgt. Cameron [Z8713] and flares dropped. Considerable S.I. jamming experienced”. The next evening one He 111 took off at 1800 and the other 12 minutes later, to protect MV Foscolo. One these jammed four frequencies but the other had receiver problems and could not complete its task; both had landed by 0226 on the 19th and 221’s Lt. Catton (HX471) reported considerable ASV interference when illuminating a convoy 99 km north of Tobruk. This airborne effort had been supplemented by the Nachtfalter (WIM stations) in Derna and Crete-West, “both to their full extent for the first time”, apparently thanks to the recent deliveries of equipment. Two jammers flew on the next night, one from 1800–0615, this exceptionally long endurance made possible by an intermediate landing. The second took off at 1815 but was back after 15 minutes due to engine trouble. During the 19th, the Kommando’s TM+KM flew from Heraklion to Kalamaki, GJ+JH making the same trip next day. “Constant S.I. jamming” was noted again on the 20th but did not prevent 221 Sqn. from finding and illuminating a convoy but a smokesreen hid any results of the ensuing strike.

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