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No 3 Telecommunication Unit (3TU)

No 3 Telecommunication Unit (3TU) was a Royal Australian Air Force (RAAF) unit which, in its 45 years of operation, received little publicity or acknowledgement. The unit performed specialist communications tasks in strategic and tactical support to the Australian Defence Force (ADF) both in Australia and overseas.

3TU was formed on 15 October 1946 as a separate unit within the command of Headquarters Western Area and was located at RAAF Station Pearce, just outside Perth, Western Australia. The unit became operational on 6 September 1947 with a complement of less than 20 officers and other ranks.

3TU is regarded as the home of the RAAF Sigsops (Signals Operators) trade, and the staff were revered for their high standard of Morse code skills, along with the unit being a significant training base for junior Sigsops.

The Operations Flight was divided into set room, traffic analysis, reporting, non-Morse search and development and training sections. 3TU was functionally controlled by the Department of Defence (Air Force Office), but operational control was effected by Australian Signals Directorate in Melbourne (variously known throughout the period as Defence Signals Bureau, Defence Signals Branch, Defence Signals Division and then Defence Signals Directorate). The achievements of the unit and the high standards of operational capability were a reflection of the cooperation and goodwill which existed between Air Force Office, DSB/DSD and the station.

3TU has made a significant contribution to the Australian signals intelligence effort, both directly and as a specialist training provider. The unit provided the ADF with communications support 24 hours a day from 1948 to the closure of the unit on 1 December 1991. When operations came to a close, a significant era of Australian defence communications ended.

Photographs and historic signals and correspondence

Collins 51-J4 receiver 3TU machine intercept receivers Operating a 3TU multi-tone position 3TU ELMUX demodulation systems General view of 3TU operations site 3TU operations building Main entrance to the 3TU set room Supervisor in 3TU set room 3TU main set room 3TU aerial amplifiers and splitters 3TU communication section tape factory 3TU hand-speed Morse position 3TU secure communications assembly 3TU KW-26 crypto consoles 3TU incinerator for classified waste

Undated, 3TU advice to DSD re planned date of transfer to new operations building (PDF)

Undated, 3TU advice to DSD re transfer to new operations building (PDF)

Undated, 3TU advice to DSD re number of channels of ELMUX equipment (PDF)

Undated, 3TU to DSD re concerns about staffing (PDF)

13 June 1963, 3TU to DSB, additional set hours for national tasks (PDF)

3 July 1963, 3TU to DSB, developments re staffing and set availability (PDF)

24 July 1963, 3TU to DSB, proposed amended times of operations (PDF)

10 September 1963, Weapons to 3TU, sloping vee aerials (PDF)

8 November 1963, DSB to 3TU, installation of additional ELMUX equipment (PDF)

23 April 1964, Department of Air to DSD, reduction of 3TU personnel due to training (PDF)

1 May 1964, DSD response to Department of Air re reduction of personnel due to training (PDF)

7 July 1964, 3TU to DSD, imminent loss of staff to operation (PDF)

11 July 1964, DSD to 3TU, re staffing and tasking (PDF)

20 August 1964, 3TU to DSD, tasking (PDF)

4 November 1964, DSD to 3TU, tasking (PDF)

11 November 1964, DSD to 3TU, on-call arrangements (PDF)

10 March 1965, 3TU to DSD, thank you from outgoing CO (PDF)

16 March 1965, DSD to 3TU, welcome to new CO (PDF)

30 September 1965, DSD to 3TU, response to proposed amended times of operation (PDF)

3 December 1965, DSD to 3TU, thanks for productivity (PDF)

21 November 1980, DSD on-site establishment review of 3TU (PDF)

30 April 1981, DSD to Defence Air Office, on-site establishment review and projected tasking (PDF)

22 September 1985, DSD request punched card equipment for 3TU (PDF)

29 March 1989, Administrative Order 4/89 to 3TU to deploy and exercise its role in a tactical environment (PDF)

28 November 1991, Air Commander to Defence Air Office, acknowledgement of service of 3TU marking unit closure (PDF)

28 November 1991, Defence Air Office to 3TU, cessation of operations (PDF)

1 December 1991, 3TU to DSD, cessation of operations (PDF)