V Geo Radar - GPR (Ground Penetrating Radar)

V Geo Radar - GPR (Ground Penetrating Radar)

vgeordrThis ground penetrating radar (GPR) has been designed specially for treasure hunting. The GPR can find subsurface heterogeneities, such a cavities, tunnels and other objects. All GPR are excellent to survey in rocks and sands, good in rather dry soils without clay, and useless in soil with clay and wet soils . For treasure hunting all GPR are useful to survey in rocks , and usually useless in soils, because of most soils have high conductivity. The obtained information immediately appears on the laptop display. The GPR can find good, subsurface cavities larges than 1metre x 1m x 1m, with an almost flat ceiling. Smaller objects will be found with difficulty and not so deeply.

The laptop can be any , with Windows XP or Vista, and USB port , 1.4GHz or more.The GPR can to be carried by a single operator. In the sounding process, the operator is getting real-time information as a radiolocation profile (radargram) on a display (on a notebook). The GPR draw the radargram for 60 seconds (in this time operator can see the received part of the radargram) , after that operator can record it on a hard disc with any name for further use, or/and start new. The GPR can scanning with the time window(time that gpr receive after transmit pulse) 50nS, 100nS or 200nS.Wen the operator carry the GPR, antennas must be from 5 to 20 centimetres over the ground surface. Distance between antennas can be from 0.5 to 1.5 metеr The antenna system is dipole, unshielded, air coupled.

Antennas :

  • 75MHz - length-1,5m, depth-10m
  • 100MHz - length-1m, depth-8m
  • 150MHz - length-0,75m, depth-6m
  • 250MHz - length-0,5m, depth-4m
  • 350MHz - length-0,3m, depth-3m

Current consumed - 0.4A from 12V battery
Weight - kg 4 with battery

Depth - detection depth - Distance between ceiling of a cave in rock(limestone) and ground surface . If a ceiling is flat or oval and cavity is large. Depth is dependent on the parameters of the rock or soil.

With the GPR you will be able to detect cavities in rock or sands with dimensions width Xm, length Xm, height Xm at a depths 2*Xm. As an example if a cave have width 2m, length 2m, height 2m and flat or oval ceiling, the GPR will can detect the cavities on depth 4m in rock.

The GPR can detect cavities in rather dry soil without clay with dimensions width Xm, length Xm, height Xm on depth Xm. As an example if the cave have width 2m, length 2m, height 2m and flat or oval ceiling, GPR will be able to detect the cave on depth 2m in soil.

m=metrе

If the ceiling is not flat or oval, or is acute, the depth is smaller.
When the soil is wet, the depth is smaller. In practice it is very difficult or impossible to predict how deep GPR can see in soil because it is depend from soils characteristics.

In the "WORLD ATLAS OF GROUND CONDUCTIVITIES" you can to see if your region is suitable for GPR survey, if a GPR will have good depth. If ground conductivity is less than 1mS/m the conditions are perfect. If ground conductivity is more than 10mS/m , GPR will be useless in this region , you can to use a GPR only on rocks in this region.

400MHz shielded antenna

400MHz resistively loaded bowtie antenna
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Example - detecting a cave in rock (limestone) , depth between ceiling of a cave and ground surface is 3m.


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1600 MHz GPR antenna

GPR and antenna 1600 MHz
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Examples:

1. Detecting a cavity in concrete in depth 15cm.Result after crossing 3 times ( slow, fast , slow ) over the cavity:

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2. Detecting a metal plate 10x50mm in concrete in depth 15cm. Result after crossing 2 times over the plate:

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