Coordinating with the British ← 07 May 1962: Relocation of HYDRA Telegraph Relay Centre 25 January 1962: HYDRA Wartime Planning → 1961-1966: “In Event of an Emergency”: HYDRA Goes to Ground Coordinating with the British The Many Heads of HYDRA: Canada as Cold War Signals Intelligence Hub Summary 1946-1949: Taking Over, Taking Shape4 April 1946: Memorandum for Mr. Robertson7 May 1946: Letter from Norman Robertson to Sir Edward Travis 7 May 1946: Letter from Norman Robertson to Charles Foulkes5 June 1946: Hydra Communications8 July 1946: HYDRA – notes from DCGS(A) 23 September 1946: HYDRA5 October 1946: Hydra Decision Delay19 October 1946: Wrinch to CGS29 November 1946: Pearson to FoulkesUndated: Hydra Project: Note of Arrangements Between the Directorate, Royal Canadian Corps of Signals, Canadian Army, And the Directorate of Special Communications, Great Britain27 January 1947: Communications - Hydra08 March 1947: SIGINT Communications North America 21 March 1947: HYDRA Arrangements21 March 1947: Transfer of HYDRA and Rockex29 March 1947: Hydra Transfer Confirmed 29 Nov 1949: Rockex Request 1957-1960: Building Links and Maintaining Ties, Alerts, and Tensions in the Line Building Links and Maintaining Ties Undated: Summary of the Development of HYDRA1955-1958: HYDRA Line Diagram 21 June 1957: Bremner to Wethey24 June 1957: Wethey to Bremner 25 November 1957: Report on Bi-conical Sector and Alto Antenna Array28 November 1957: Forwarding Report on Bi-conical Sector and Alto Antenna Array 08 January 1958: Loan of Coquelet Terminal Equipment 12 May 1958: Bremner Visit08 September 1959: Rockex Maintenance Strategic Warning: HYDRA and Tripartite Alerts23 August 1957: Dean to Crean 10 September 1957: Crean to Peck 25 August 1959, 01 September 1959: Mathews and Grant on Power Cut16 February 1960: Emergency Power Supplies Tensions in the Line11 April 1956: Foulkes to Leger February 1958 to March 1958: Teletype Circuit New York Ottawa26 May 1958: Line Circuits – Ottawa Traffic Center 1958-1959: HYDRA Communication System – Estimate of Cost to Department of National Defence (Army) Notes 03 November 1958: HYDRA Communication System 20 February 1959: CSB 24/Item 2(b) Survey of Operation of the HYDRA System25 September 1959: Draft Unsent Letter to Starnes28 September 1959: OTC Circuit Rearrangement 1961-1966: “In Event of an Emergency”: HYDRA Goes to Ground National Defence Landline Restoration Planning 08 July 1960: Note to File: HYDRA Communications 26 August 1960: Leased Landline Circuits Priority of Restoration 12 October 1960: Leased Landline Circuits Priority of Restoration25 July 1961: Leased Landline Circuits Priority of Restoration14 March 1962: Draft D Sigs Technical Bulletin 63/Protected Leased Circuits18 April 1963: Protection of Cable StationsThe Proposal: Moving HYDRA UndergroundUndated: HYDRA Planning28 April 1961: HYDRA Emergency Plan 12 June 1961: Fallout Protection Oshawa Wireless Station12 April 1962: Relocation of HYDRA Telegraph Relay Centre17 April 1962: Expansion of EASE Automatic Telegraph Relay Centre/Relocation of HYDRA Telegraph Relay Centre07 May 1962: Relocation of HYDRA Telegraph Relay CentreCoordinating with the British25 January 1962: HYDRA Wartime PlanningUndated: Diplomatic Wireless Service HYDRA Routing Chart26 April 1962: Tait Visit to UK11 May 1962: HYDRA Roadblock 16 May 1962: HYDRA Roadblock28 May 1962: Hydra Communications System 27 June 1962: HYDRA U.K. Engineer Visit14 August 1962: STRAD and HYDRA13 September 1962: STRAD HYDRA Handling 18 September 1962: STRAD HYDRA Handling02 April 1963: Sharpe Visit 01 May 1963: Summary of Discussion at Meeting Held 18 April 196305 November 1963: STRAD Black Box04 November 1963: STRAD Black Box06 December 1963: STRAD Black Box08 April 1964: EDC, Piccolo22 May 1964: Alerts Black Box30 Jun 1964: Alerts Black BoxCoordinating with the Americans10 January 1963: CAN-UK JCECS - US MCEB Methods and Procedures Panels Directive ACP 121 Communication Instructions - Message Precedence Categories16 October 1963: ACP 121 Communication Instruction General Message Precedence Categories17 October 1963: ACP 121Coordinating with Users24 June 1965: HYDRA Circuits23 June 1965: HYDRA CircuitsUndated: HYDRA Control Position Design and Operating Concepts29 June 1965: Communication Instructions HYDRA Service Procedures (HSP 101) Planning Runs into Difficulties30 April 1965: Relocation of HYDRA to Carp2 Jun 1965: Relocation of HYDRA Relay and Radio Centre Operating Personnel11 May 1965: Relocation of HYDRA11 June 1965: Relocation of HYDRA Relay and Radio Centre Operating Personnel09 September 1965: HYDRA System Problems28 January 1966: HYDRA System Problems18 November 1965: HYDRA Message Length"Record of Meeting": HYDRA Relocation and Forces Integration27 May 1965: Record of Meeting: Relocation of HYDRA Relay and Radio Centre28 June 1965: Record of Meeting: Relocation of HYDRA Relay and Radio Centre30 July 1965: Record of Fourth Meeting Relocation of Hydra Relay and Radio Centre13 October 1965: Record of Fifth Meeting Relocation of HYDRA Relay and Radio Centre17 November 1965: Relocation of HYDRA Working Group- Procedure for Cutover Telegraph Relay Operations1966-1971: Heads and Tails: The End of HYDRA? 17 May 1966: Relocation of HYDRA Relay and Radio Centre31 August 1966: Hydra Working Group – Meeting28 September 1966: Provision of Tripartite Intelligence Conference Network06 January 1967: Delay in retermination of NSA-Leitrim Circuit28 July 1967: Engineering Difficulties, Washington British Embassy Circuit 17 August 1967: Engineering Difficulties, Washington British Embassy Circuit30 January 1968: Closure of Oshawa Transmitting Station30 January 1968: Oshawa Transmitting Station (II) 29 February 1968: Note to File - Closure of Oshawa Transmitting Station23 April 1971: HYDRA Diplomatic CCTs