Airborne Cigar, or ABC for short, was a World War II electronic countermeasure (ECM) system developed by the Telecommunications Research Establishment (TRE) to jam Luftwaffe ground-to-air radios operating in the very high frequency (VHF) band. When used properly, the system made enemy night fighter communications almost impossible. The Germans referred to ABC as "dudelsack", German for bagpipes, in reference to the warbling sound.[1][2]
The system consisted of a wide-band receiver and three tunable transmitters of about 50 W output. The German-speaking Special Duties Operators (SDOs) would listen to signals in the band to determine which frequencies were being used by ground controllers. When one was found, one of the transmitters would be turned to that frequency and begin broadcasting noise. ABC was operated primarily by No. 101 Squadron RAF, part of the specialist No. 100 Group RAF. As the system was only useful over a range of about 50 miles (80 km), their Lancasters were spread out through the bomber stream. Because ABC was used on almost every mission, 101 suffered among the highest losses of the war.
To counteract ABC, the Germans introduced new frequency bands. These were soon discovered and jammed as well. Other attempts, like false ground controllers, using women to send the signals, and other methods, all had little effect, and no effective countermeasure to ABC was found. ABC was later supplanted by Jostle IV, which barraged the entire band beginning on 30 June 1944. The ABC systems moved to No. 462 Squadron RAAF in March 1945. After the war, they were moved to No. 199 Squadron RAF and in 1958 to No. 18 Squadron RAF, ending their long career on the Vickers Valiant.
- ^ Instrell 2008.
- ^ Sugarman 2001, p. 190.