The survey was undertaken using four Bartington Grad601 sensors mounted at 1m intervals (1m traverse interval) onto a rigid carrying frame. The system was programmed to take readings at a frequency of 10Hz (allowing for a 10-15cm sample interval) on roaming traverses (swaths) 4m apart. These readings were stored on an external weatherproof laptop and later downloaded for processing and interpretation. The system was linked to a Trimble R8s Real Time Kinetic (RTK) differential Global Positioning System (dGPS) outputting in NMEA mode to ensure a high positional accuracy for each data point, in accordance with EAC guidelines (EAC 2016). The survey has not identified any anomalies of definite or possible archaeological origin. A variable magnetic background is caused by a moderate spread of discrete low to high magnitude anomalies likely derived from the spreading of 'green waste' as a soil conditioner. The density and strength of these anomalies however has not prevented the identification of a pattern of field drains and is not deemed to necessarily preclude the identification of magnetically weaker anomalies of possible archaeological origin. Overall, the findings of the survey reflect the limited archaeological potential of the Site which is not recorded as within a RAZ and that was identified in the Historic Environment search conducted for the HS2 Environmental Statement and LiDAR/ Remote sensing survey data which did not identify any features within the Site.
Matt Berry (Sat,) studied this question.