Turning to live operations, two Wildschwein He 111 were assigned to the convoy, taking off at 1915 and 2215. They jammed four frequencies between 2018 and 0115 and two from 0055–0307 and both aircraft had landed by 0407 hours. A very fragmentary intercept of the 6th refers to two jamming aircraft, one apparently operating along a defined line and transmitting from 1800–2300 hours but it is not clear if results or intentions are being reported but the Kommando’s He 111 GJ+JH made a flight from Kalamaki to Heraklion that day. To help ensure the convoy’s safe passage on the night of the 7/8th, a Kdo. Koch He 111 was up at 1610 while an hour later 13 Ju 88 of KG 77 took off for an attack on RAF Shallufa near Suez, intended to cripple the ASV and anti-shipping Wellingtons thought (correctly) to be based there. Next day the Zentrale asked Derna if “the Nachtfalter sets” or »WIM-Maschine« were being heard, on which frequencies and at what strength. An intercept from Derna that day may have been the response to this inquiry:
Nachtfalter has not been heard. A fresh apparatus is urgently required. No longer ready for operation as from 0015 hours
Over Egypt late on the 6th, P/O J.A. White and Sgt. K.F.G. Inskip (Beaufighter 7708 of No. 46 Squadron) reported obtaining a poor contact which was then lost in interference. Early on 7 September, RAF Middle East had advised No. 201 (Naval Co-operation) Group that jamming was a possibility and to have an alternative frequency ready for use if it was encountered. In addition a direction-finding watch had been instituted so that spoof messages could be identified.
WIM 1 at Noto gave warning that it would be out of action between 1230 and 1430 on the 8th “because of a change of position” (perhaps due to the works underway at the site, see below). Meanwhile, further instances of jamming had been reported at 1110 on 6 September, 2140 on the 7th, 0100 on the 8th and 0130 on the 9th. Radar stations in Egypt were logging numerous cases every day in early September, most some form of continuous wave transmission, but one in the Alexandria area on the night of the 7th is notable in that: “Bearings from Burg-el-Arab varied between 125º and 281º, following approximately a hostile RDF track approaching from the west”. Summing up on 15 September the RAF stated that:
[In Egypt and the Western Desert] The jamming of AI is the worst aspect … A very small amount of ASV jamming has been reported. This appears to originate from ground or possibly ship borne sources.
Malta is experiencing the most intense form of jamming the enemy has so far shown himself capable of. He has a suitable site on high ground in Sicily from which a ground station is easily able to flood Malta with interference.
No. 13 Sector Operations Room had this to say about interference with their VHF frequencies on the night of the 7th:
… associating itself with Raid 9, [it] commenced in the neighbourhood of El Daba and took a generally South Easterly course towards Cairo, returning towards enemy occupied territory, at first on a Westerly course changing to North West.
As on previous occasions the interference took the form of a low hum, similar to ignition noise but seemed to have a musical note of about 400 cycles imposed on it.
In a cypher message of 11 September, S/L Scott Farnie was able to tell his chiefs in London, of preliminary evidence from shot down KG 77 crewmen that Caruso had been in use for three or four months, fitted to perhaps one machine per Staffel. The device was turned on in the air, taking around five minutes to warm up, and was activated in earnest by the air gunner, on orders from his pilot; while transmitting, it rendered the carrier aircraft’s radios and intercom unusable. The equipment was installed in the rear fuselage and had four horizontal antennae mounted near the tail. The prisoners’ aircraft was thought to be in Lake Faiyum, 75 km SW Cairo, and arrangements had been made for divers to make “strenuous efforts to salvage [it]”. According to a report dated 19 September, prisoners from the same Geschwader had described Caruso as a device for jamming RAF night fighter radars. It was said to operate in the VHF waveband and to be housed in a casing 30 x 15 x 15 cm. These men claimed that it was switched on prior to take-off and continued transmitting throughout the flight but was not thought very effective and was not in general use.
A Wildschwein He 111 “carried out a raid” (in G/C Cadell’s words) from 0700 on 10 September. Its transmitters were tuned to 173, 180, 190 and 200 mHz and WIM 7 (Derna), 9 (El Daba) and 1 (Noto) were to report the results to the Zentrale. Since this took place in daylight, it seems more likely that the Heinkel was making another test flight. Fliegerkorps X broke a habit on the 11th; normally when it reported the strength of its constituent units it named them only as “(a), (b), (c)” etc. but today’s return was explicit and included:
Sonderkommando Koch, Kalamaki: 3 (2) He 111 H-6, 1 (1) Ju 88 D-5 and 4 (3) crews.
The lone Ju 88 would appear to be the Lichtenstein-equipped machine mentioned earlier but it is unclear what had happened to Ju 52 NR+AE (see below however).
The Kriegsmarine’s dismal conclusion on 8 September was that: "we are not equipped at present to deal with the highly superior skill of the RAF in night operations at sea". Three days later however there was a hopeful note: "The newly developed radar set … (‘Hohentwiel’) has a range of 15 km at an altitude of 50 m and … 400 km at …1000 m. It thus approximates the performance of British equipment." Conversely, the RAF's Middle East Operational Research Section summed up the position with jamming thus: "The trouble became more and more serious during September and October."
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