Starnberg

The »Starnberg« W/T jammer

Late in February 1944, the French-based II./Luftnachrichten Funkhorch-Regiment West reported to a visiting delegation from the RLM on comparative trials of two W/T jammers, Starnberg II and Nervtöter (“annoyance”). The latter had been judged a failure with experienced Telefunken engineers unable to keep it set to the required frequency, even when they knew in advance which one they were to jam. Nervtöter needed constant attention while in the air and sufficiently accurate tuning was impossible. In December the set was being developed further ‘along Chef TLR’s guidelines” but no date could be given fro the completion of this work. Starnberg by contrast was producing good jamming effects over a range of 30–50 km while flying at 2000 m and was effective out to 40 km when at an altitude of 150 m. Some 25 Starnberg II sets had been produced by 21 February; now they only awaited tuning-in, and two engineers from Köthen were requested for this task. A production set was currently being installed in a Ju 188 by the Villacoublay workshops and should be ready by the end of the month.

Given the planned operating altitude of 7000 m, the antennae were being installed in the wings, pointing downward but could easily be changed to radiate upward. The jammer had an output power of 30–50 Watts. Three, aircraft, each with two transmitters, their frequencies set narrowly apart, could cover the 100–124 MHz waveband and effectiveness would be increased if there was multiple coverage of the band. It was envisaged that machines carrying jammers would be deployed in the van, middle and rear of the bomber stream. Further conversions could be carried out using about 50 French-built “replica” Starnberg I and the necessary parts for the installation would be indented for shortly from the RLM’s Chief of Signals. If the transmitters were required in greater numbers, orders must be placed as quickly as possible but none of the components was in short supply. The plan was that II./KG 6 should receive the first Starnberg while II./KG 2 would get Kettenhund.

NOTE:

Within three months of the RLM party reporting, much of what it learned about Starnberg also became known to the Allies through the capture of members of the trials Ju 188’s crew. Ltn. Gerhard Wenz (pilot), Uffz. Karl Fritsch (observer) and Uffz. Karl Hoyer (flight mechanic), all of 2./KG 6), bailed out over Somerset in the early hours of 15 May after their plane was hit by a night fighter. They told interrogators that they had been selected to take part in Starnberg trials and had flown a Ju 188 to Villacoublay to be fitted out, a job not completed for three weeks. After that aerodrome was bombed, testing was transferred to Orly from where he Ju 188 would take off and fly at 8,000 m to Bourges. Then the Starnberg was activated and the aircraft turned back for Paris where a radio salvaged from an RAF bomber had been installed atop the Eiffel Tower. The prisoners were told that their jamming could be detected at 200 km, becoming “extremely effective” at 20 km.

Starnberg had been installed in the Ju 188’s rear fuselage with 50 cm dipole antennae under each wing. The jammer was set to the required frequency before take-off and the Bordfunker’s only controls were two switches, one to heat the set and the other for its transformer. The trials were considered successful, the gear was dismantled and taken back to Germany. The civilian engineer in charge, Herr Böhmlein, saying that the system would now go into production and be delivered to the Gruppe by the end of May.

A memo to the Luftwaffe’s Head of Signals dated 4 July 1944 reported on progress in fulfilling an order for Starnberg transmitters placed on 17 May, “In addition to the 24 completed so far and the 50 under construction [covering] the 98–120 MHz waveband, [the following] have been ordered: another 50 on the same waveband and 125 in the waveband 120–156 MHz.” The fighter force meanwhile was asking for two batches each of 100 sets covering 98–156 MHz. A paper apparently from December 1944 (the date is partly obscured) gives Köthen’s verdict as “jamming effect insufficient”.

»Düppel« radar reflector strips

At the end of February, IX. Fliegerkorps had reported good results with 80 cm Düppel strips in its most recent raids on London. Radio monitoring had revealed confusion within the British reporting organisation, night fighters had chased one another on several occasions and searchlight beams had been lowered. Anti-aircraft fire however had been well-aimed. From 50 km off the enemy coast each heavy bomber’s Bordmechaniker dispensed 1,000 Düppel strips every 30 seconds, intensify to 1,000 strips every 5 seconds over the target. A heavy bomber could carry two packets of Düppel. (In this context, "heavy bomber" probably covers all except the Me 410s and Fw 190s operating in support of the main force). Oberleutnants Albert Frankford and Peter Berresheim of the IX. Fl.Kps. Signals Staff told their visitors that on raids their aircraft flew in “the greatest possible concentration”: bomber stream 80 km in length by 10 km wide, duration of attack 15 minutes. This seems highly optimistic in view of the often haphazard, even shambolic, incursions reported by the RAF during the “Baby Blitz”.

In November 1944 guidelines were issued for the operational deployment of Düppel; there were standard sizes:

Dimensions	Against wavelengths	Weight
250 x 5 cm	2.5–6.0 m	20–25 g
80 x 2 cm	1–2.5 m	2–3 g
4.5 cm	9 cm	500 g (per packet)

Ten of the long strips or 50 of the medium ones were said to give a reflection equivalent to an He 111; falling from 6000 m the long strips remained effective for about 30 minutes and was best from somewhat above the operating altitude of the main force.

Sources

The National Archives, Kew, London:

AIR 14/2898: Enemy Radar Jammers “Airborne” (May 1944)

AIR 20/8964: Enemy Countermeasures to RDF, Jamming Reports (J. Watch) Western Europe: Sep 43–July 44

AIR 40/2417: Interrogation of German and Italian Prisoners of War, Vol. 22, Reports 153–322 (1 April–30 June 1944)

AVIA 6/14410: Royal Aircraft Establishment Farnborough, Technical Note No. Rad. 170, “Anti-Jamming Measures for A.S.V. Mark II” (November 1943)

Canadian Department of National Defence:

Directorate of History and Heritage, Kardex system (Reel T-2422): http://heritage.canadiana.ca/view/oocihm.lac_reel_t2422/1?r=0&s=1

USAF Historical Research Agency, Maxwell AFB, AL:

Chef NVW 4. Abt. (III): Aktenvermerk über die Dientstreise des Gruppenleiters III in den Bereich der Luftflotte 3 vom. 18.2. – 28.2.44 (dated 11 March 1944)

Bundesarchiv-Militärarchiv, Feiburg-im-Breisgau:

RL 2-V/30: Generalnachrichtenführer, Anlagenband A 3 (Stördienst) (Juni 1944–März 1945)

RL 2-V/57: Einsatzrichtlinien für den Düppel-Abwurf (Nov. 1944)

RL 2-V/61: Funkmeßgeräte.- Stand der Erfüllung der taktisch-technischen Forderungen (Jan.–Mai 1944)

RL 2-V/209: Brandt, Leo: Deutsche Gegenmaßnahmen gegen feindliche Funk-Navigation 1942-1945

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