In case it is necessary to adopt crude counter measures, bombing the enemy transmitters must be considered one of the best.

Air Scientific Intelligence Report No. 10 (12 January 1941)

An order was circulated among the stations on 30 September 1940 for them to submit reports on the “effects of enemy bombs, artillery etc.” since each installation had been built. In future there were to be daily returns of attacks on transmitters, control posts and crew quarters, giving details such as the number of bombs and how far away they had fallen. So far as I am aware, this was before the British had made any deliberate effort to destroy the installations.

At most of the locations there was nothing to relate but two heavy bombs had fallen 800 m north of ODER at 0200 GMT on 24 September. The hostile aircraft was thought to have been flying at 3000 m and there plenty of reasons for an RAF bomber to have been over the Cap Gris Nez – Boulogne area at the time, not least to attack invasion barges. Later, other stations were able to report hostile aircraft passing overhead and being engaged by the local Flak but without any actual attack.

At 0600 on 12 October, Ltn. Tietze at DONAU advised that the Den Helder area had been repeatedly bombed over the last few nights and that “yesterday” (the time unstated) HE and incendiary bombs had fallen very close to the crew’s living quarters. On the 14th came an incident alarming enough for Tietze to report it to Ambleteuse within 10 minutes and for Stabsing. Dr. Fischer to follow up to Dr. Kühnhold within the hour. At 1130, a single Blenheim had dived to 150 m and released three “heavy bombs” which fell 200 m from DONAU but caused no damage to the installation. The Blenheim seems to have been T1871, XD⦿T of No. 139 Squadron whose pilot, S/L Mertens, reported dropping his bombs on a railway line near De Kooy aerodrome after a shell had damaged his aircraft. (Mertens’ crew was completed by Sgts. Miller and Mansfield; their Blenheim carried 4 x 250 lb delayed action bombs). In the day’s situation report the events were summarised as: “1320–1325 [GMT+2], De Kooy, 4 x HE (1 dud), dropped near a Luftwaffe signals outpost, no damage”

Clearly disconcerted by the incident, Tietze asked if Flak protection could be made available and whether the station should continue operating or be removed to a place of safety, receiving the prompt reply that no operations were expected in the near future so he should indeed take the latter course. By 16 October the “apparatus” had been moved to a safer place and instructions were sought on whether the generators should also taken off-site. Dr. Fischer proposed that “if operations from this station are important”, DONAU should have a new layout, secure against enemy attack. He wanted to put the equipment and personnel in an existing pill box and to operate from there a “simplified turntable” (the antenna array) via a long cable. Anxieties had probably been kept alive by two parachute flares dropped over »Kontrollstrecke« (“control path”, a line of reference points for calibrating the beam) about 350 m from the station, at 0230 that morning. In the event, DONAU was relocated before it began operations. Signals showed that the Germans were very nervous about all the transmitters’ safety, describing them as “enormously important” and “most difficult to replace.” Urgent steps were taken to provide hardened accommodation for personnel, to camouflage the installations and ensure that any threatening enemy action was reported.

Ambleteuse had again been bombed in the meantime, from 2200–2300 hrs. on 12 October: seven bombs had fallen about 150 m from the crew’s quarters. It was reported on 16 October that three light bombs had come down 300 m north of ISAR (Ambleteuse) and another three 200 m from the “company” (the signals unit’s HQ or quarters, perhaps?). Two days later, at 0830 hrs. two artillery shells landed 400 m from ISAR and there was a parachute flare over the station at 0300 on the 26th. Later that morning there were aircraft flying over, engaged by the Flak, and the cross-channel artillery was once again active. Isolated raids and hostile aircraft continued to be reported over the following days but with no indication that the station itself was the target. On 2 November it was ELBE’s turn, a bomb falling 200 m from the control post’s “Stake 6” (i.e. one of the calibration points).

PART TWO OF TWO