[Shielding: Radar] [Shielding: Clay] Making wet saline clay. Add clay to sea water
Though the clay packs I have tested are thin, they effectively shield maser and laser attacks. I have purchased more. The clay is immersed in a liquid. I will be experimenting making my own thicker wet saline clay packs using ice bags, recycled water bottles, recycled one gallon milk jugs and 5 gallon gasoline tanks fillled with water, sea salt and clay. See the post on clay packs:
Dense wet clays are the most difficult material to penetrate whereas clean dry sand is the easiest......Radar is the only remote sensing technology that can detect both conductive and non-conductive materials. Although radar can easily see conductive materials such as metal and salt water, it cannot see through them.
http://www.usradar.com/about-ground-penetrating-radar-gpr/faq/
This article was revised in 1997. High tech development of ground penetrating radar (GPR) since then can penetrate wet clay more than a few feet but remains an excellent shielding material.
Absorption of radar signals in the earth is dependent on a soil or rock's moisture content, and especially the salt content of that moisture. Clay soils have by nature very high radar losses because of their molecular ionic structure. In wet clay soils it is often impossible for a GPR to penetrate deeper than a few feet no matter how much transmitter power is available. In dry or otherwise favorable rock types 100 to 300 feet of penetration is often possible. Volcanic soils (characteristic of the Philippines) are variable in their conductivity but often reasonably favorable for radar propagation.
http://www.ldolphin.org/GPRbkgnd.html
Electrical Conductivity Effects on Penetration
The ability of a material to conduct electric current. The value is primarily controlled by water content and/or clay content. Higher conductivity make radar signal penetration difficult:
Low Conductivity Excellent Radar Conditions 3 4 meters deep
Air, concrete, asphalt, dry limestone and granite
Medium Conductivity Average Radar Conditions 2 meters deep
Freshwater, ice, snow, sand, silt, dry clay, seawater ice
High Conductivity Poor Radar Conditions about 1 1.5 meters
Wet clay, wet shale, seawater
Materials Dielectric Constant Radar Propagation velocity
Water (Fresh) 81 0.033
(Sea water is not listed.)
Dry sand 4-6 0.15 - 0.12
Wet sand 30 0.05
Dry clay 8 .11
Wet clay 33 0.05
From Table 1, page 3 of
Huge difference between wet soil and dry soil. Wet sand almost attenuates radar as much as wet clay. Table 2 on page 12 contradicted Table 1 by claiming wet sand is not as attenuating as wet clay:
Table 2
Good radar media: dry salt snow ice and fresh water peat wet or dry sand dry rocks
Poor radar media: salt water metals clay clay-rich soils conductive minerals
Peat was listed as good radar media. Danny Hunt purchased peat based on "wet foliage" attenuating radar. Wet foliage isn't even discussed in these articles. Peat would need to be and stay wet and isn't as effective as wet saline clay.
To summarize, the deepest penetration will occur in dry, nonclayey soils, and in dry rocks with no clay cementation. Snow and ice cover (and permafrost) will not adversely affect GPR data. When the soils or rocks are saturated, the conductive nature of the filling liquid becomes important. Fresh water is the most favorable for radar penetration.
From page 10:
Because an increase in moisture content dramatically reduces radar propagation velocity (increases
dielectric constant), the average dielectric constant is often proportional to the water saturation of the soils/rock in the subsurface.
From page 14:
Clay minerals
When clay minerals are present in the rocks and soils, dissolution will create ionic solutes. These ions become mobilized in saturated pore space, and conductivity increases. The presence of clay minerals will tend to increase conductivity and thus increase the amount of conductive attenuation. It is hard for radar to
"see through" clayey soils.
To increase minerals in clay, add sea salt. Saline wet clay's attenuation may be higher than seawater.
Posted Apr 4, 2017, 11:42 PM UTC · edited