[ Pobierz całość w formacie PDF ]
.Photographic recording equipment,code-named Willie and Oswald , would allow post-event analysis of firings to improveintelligence about V-2 performance and to refine site location.Installation of thisequipment was complete at all five stations by the end of October.126By this time, however, further intelligence indicated that the V-2 might be launchedfrom ranges as great as 200 miles, and that it might present a weaker radar signature thanpreviously anticipated.The greater demands this placed on radar meant that the twintasks of early warning and site location were now considered incompatible.In view of thescale of the photo-reconnaissance efforts being devoted to V-weapon sites, it was decidedin March 1944 to concentrate the radars on the early warning task.It was also decided notto extend the rocket warning chain further along the south coast, facing the Cherbourgpeninsula, in view of the approach of D-Day, which would forestall rocket launches fromthat area.Additional radar sites were added to the system further east instead.Two special high-looking radars (Air Ministry Experimental Station [AMES] 9) were installed at Martin sHill and Snap Hill,127 and additional CRDF sets at Ramsgate and Dymchurch on thesouth coast and Bawdsey, Bromley and High Street on the east coast,128 the latter threelooking east towards the Low Countries rather than south and south-east towards France.These radars would provide early warning as the rockets climbed.To provide terminal-phase detection, 11 Army GL Mark II radars were deployed, 20 30 miles apart, betweenNorth Foreland and Portsmouth.All were in place by late August 1944.A Big Ben reporting exercise conducted by the headquarters of ADGB on 26 Augustproved satisfactory.Warning times of up to 205 seconds were expected from the longer-range radars and 90 seconds from the army sets.129 The point of strike was predicted bythe Army s existing AA Command Prediction System,130 though as this could beachieved only 70 seconds before impact it was of limited utility.On 6 September, however, in view of the advance of Allied armies in France, the ViceCoS agreed that V-2 attacks on London were no longer expected.The official history The wartime V-2 Experience 19states that the first opportunity was taken for discounting a threat which had always beenan irritating diversion from the last great offensive.131 This did not tally with theintelligence about the V-2 held by Hill s staff at ADGB, and radar watch was maintainedin case rockets were fired at targets other than London.132The radar watch for rockets was supplemented by Royal Artillery counter-batteryflash-spotting and sound-ranging techniques.As early as April 1943 General Nye s reporton the long-range rocket133 recommended the use of flash spotting to detect expected V-2 ranging-shots (following the artillery analogy).By August 1944 11th Survey Regiment,based at Canterbury, was integrated with the various radar stations in providing rocketdata to Stanmore.Sound-ranging employed a chain of microphones whilst flash-spottingsought to detect the exhaust plume of rocket launches, employing three balloons to raisethe observers aloft.134 Both had some early success in detecting actual V-2 launches.135Flash-spotting was effective at ranges of up to 150 km in good weather.136The tasking of Bawdsey on the east coast for rocket-watching was fortuitous, for thefirst two V-2s launched on 8 September were fired, not from northern France aspreviously anticipated, but from the Netherlands.Although the rockets were not detectedby radar at the time, subsequent examination of the photographic records showed thetrack of a projectile at a range of 135 miles.137 Of the first 25 V-2s, only 28 per cent weredetected by radar operators at the time, most of the remainder being found on subsequentexamination of the film records.138 By the end of October, 49 out of 50 incidents hadbeen caught on the cameras, and by triangulation of these records launch site positionscould be established with an accuracy of a few kilometres [ Pobierz całość w formacie PDF ]