page_title: Operational instruments of the Royal Observer Corps
section_title: Portable measurement of radiation during Mobile Monitoring missions
hierarchical_section_title: Operational instruments of the Royal Observer Corps / Portable measurement of radiation during Mobile Monitoring missions
caption_attribution_description: Photo showing the PDRM82 used by the Royal Observer Corps.
context_page_description: The Royal Observer Corps was a civil defence organisation operating in the United Kingdom between October 1925 and 31 December 1995, when the Corps' civilian volunteers were stood down. Composed mainly of civilian spare-time volunteers, ROC personnel wore a Royal Air Force style uniform and latterly came under the administrative control of RAF Strike Command and the operational control of the Home Office. Civilian volunteers were trained and administered by a small cadre of professional full-time officers under the command of the Commandant Royal Observer Corps; a serving RAF Air Commodore.
  This sub article lists and describes the instruments used by the ROC in their nuclear detection and reporting role during the Cold War period.
context_section_description: The Radiac Survey Meter No 2 or RSM was a 1955-meter which measured gamma and beta radiation. Having been superseded within the ROC by the Fixed Survey Meter the RSM remained in use only for post attack mobile monitoring missions in a post attack period. Image can be seen in ‘Static measurement of ionising radiation’ section. 
  
  The Radiac Survey Meter, Lightweight, MkVI, produced by the AVO company (The MkIII and MkIV were also available) were issued to the ROC in the mid-late 1960s, but were not regarded favourable due to using almost obsolete Mallory batteries and were ionisation type meters that measured gamma radiation.
  
  The PDRM82 or Portable Dose Rate Meter was the standard portable version of the new meters, that were manufactured by Plessey and introduced during the 1980s, giving more accurate readings and using standard 'C' cell torch batteries that lasted many times longer, up to 400 hours of operation. The compact and robust instruments were housed in sturdy orange coloured polycarbonate cases and had clear liquid crystal displays. The Radiac sensor was self-contained within the casing.
caption: Plessey PDRM82.
exif: {"Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "90", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "274", "Thumbnail JPEGInterchangeFormatLength": "5881", "EXIF ExifVersion": "0221", "EXIF ComponentsConfiguration": "YCbCr", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1600", "EXIF ExifImageLength": "900", "EXIF SceneCaptureType": "Standard"}