After you let the instrument warm up, you can check to see if your survey wear is metal free by running the Grad 601-2 in SCAN mode and moving your body around the sensors paying particular attention to your shoes, waistline, wrists and headgear. It is important that the user be absolutely metal free for the survey.
For more detail on this and other aspects of instrument or survey methods, see the Bartington Grad601-2 survey manual. To achieve this density of readings, the surveyor will need to plot a survey strategy that has overlapping coverage under the span of the trapeze.
The Grad601-2 has two gradiometers mounted on a trapeze that is one meter long, but archaeological surveys are often conducted at 50cm resolution. Surveys are most often conducted by methodically covering 20 x 20 meter squares set in a grid. These instructions assume that you have a survey area selected and gridded for survey. The following is a simplified version of the concepts and steps described in the Bartington Grad601-2 manual colored with some of the practices and preferences of the author. Written for the geophysical field school at Tell el-Amarna, January, 2011 Using the Bartington Grad 601 with Two Sensors in the Field Using the Bartington Grad 601 with Two Sensors in the Field This will result in a hard shut down of the system. In this case, press down the power button and wait for three beeps (beep. *If the fan has not turned off after several minutes, and it is not excessively hot outside, the scanner may not have shutdown properly. NEVER take the scanner off the tripod until it has completely shut down and the FAN HAS TURNED OFF*.Select Sc+Img or Scan button depending on whether you want to collect color or not.Set the image exposure in the ImgCtr window.Set desired resolution in Resolution window.Set desired scan field in Fld of View window.DO NOT click ‘Cont’ as this will add more data into STN1. Fine tune using digital level in the Level and Laser Plummet menu.Level tribrach before turning scanner on.Do not let go of the top handle until the scanner is fully secured on the tripod. Always pick up scanner with two hands – one ALWAYS on the top handle.Photograph scanner location if desired.Check to ensure glass window and lens are free of dust, smudges and fogging.
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