Website Last Updated : 22-OCT-2023
|Additional sites added to the EMSS network diagram. New map of Leamington Spa Tier 2 interconnection to its Tier 3 sites. Emergency Manual Switchboard System Page.
|Complete rewrite of the Speech Multiplex page to add additional diagrams and more detail of the technique used in the analogue communications era. It played an important part in 'MOULD', 'All Underground', 'Backbone Microwave' and 'RN1 & RN2' Home Office radio networks, as well a public and private company's communications networks.
|Paul Lawrence has kindly shared 15 detailed photos of his new GZI Instrument, added to a new gallery in Chapter 3 The ROC Monitoring Post Page.
|Added a full technical description of HANDEL written by its BT designer Neil Harding to Chapter 11 Second Generation HANDEL and Carrier Broadcast Part-1 Page.
|Revised Chapter 28, additional detail on the GPO/BT Defence Network topic.
|Top of page Navigation Bar changed to reflect limited choice of Alphabetical Index, Chapter Index or Home Page, introduced on 20/05/2021. Now offers single click access to the indexes.
|Mark P has kindly supplied detailed photographs of the second generation BE525 ROC Post radio, added to gallery on ROC Post radio communications page.
|Wartime Broadcasting Service: Phase 3 and additional information from National Archives declassified files kindly supplied by Dave G1JWG (www.radiohistory.uk) updating a brief outline of WTBS page.
|Added the Carmarthen Carrier Area to the map originally showing Swansea CCA. WB1400 Distribution page.
|No change to website content. Although browsing with mobile phones is not recommended due to the large textual content, changes to Gallery Viewer renders larger buttons, tapping the image cycles through gallery, which should help phone users.
|Replaced WB1400 Carrier Control Area map with a larger example, now showing Swansea with its network of 48 exchanges. WB1400 Part 1 of 2. Updated MOULD with additional channel list PDF files sorted by various headings. Channel allocations for six variants of Pye Pegasus wireless sets added. New listing of Simplex and MIV frequencies added.
|New navigation concept introduced to access a Chapter Index, where each page represents a chapter. The Alphabetical Index now shows the chapter containing the item.
|Split mains powered sirens and their control gear into two shorter pages but no additional material added. Pt.1) Mains Powered Siren photos of sirens, heater elements, weatherproofing, Audible testing. Field trial of pneumatic siren. Pt.2) Siren Installations,Siren Station, Switch Panels, Autowailer.
|Implemented user choice of Dark Mode colour scheme. Added a new page Wartime Broadcasting Service a brief outline of WTBS.
|Added technical details of Switching Capability in a optional openable section including opening dates, circuit quantities and electrical power provision at Birmingham Anchor and London Kingsway exchanges War Resilient Communications page.
|Addition of London Kingsway and Manchester Guardian tunnel layout plans and galleries of photographs held in BT Archives. Underground exchanges are topic 3 of 4 on War Resilient Communications page.
|Minor changes to Speech plus Duplex text, now identifying the units as 'Panel, Telegraph 107A and 108A and replacement diagram. Page Lines carrying both Speech and Telegraph signals. Additional tables, diagram and description of SCVF signalling. 2nd. Generation County Telegraph Network
|Reorganised two pages relating to ROC Posts comms into separate radio and landline pages, removing duplications and adding more detail. Added RN2 details for Cornwall LAEC, connection of F496 and DLM1. Core Network / Second Generation
|Photos added: PDRM82 Gallery includes photo of detector head wired to PDRM Post Instruments page. New section with photo added to Training CCP users to WB1400 page.
|Joachim Schmidt has drawn my attention to a Home Office field trial in 1969/70 of pneumatic sirens, of German design. Details added to Siren Page The Hormann siren features briefly in the video 'Sound an Alarm' at 8:28. Added details from Archives, HO393/63 in a new topic "Audible Testing" on siren page, confirming no testing took place from 1966 to end of Cold War.
|Paul Lawrence has kindly allowed me to photograph the inside of his WB1400 CCP, see CCP Gallery. His siren weatherproof cover assembly New Section. Replacement and improved photographs of a WB1400 era version of a Siren Switch panel. Plus additional photographs of a siren pole cap, WB1400 Signalling Receiver circuit board. Photo from Alistair McCann of spent maroon rockets added to gallery on page Post Instruments.
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