1-1. GENERAL OPERATION

TM 5-6635-386-12&P Unpacking Damage upon receipt is the responsibility of the freight company. A claim should be filed with the freight company for damage. If the radioactive source may have been damaged, see Para 4-31. 1-1. GENERAL OPERATION The tester is ready for use after unpacking. There are no adjustments in the tester. All settings are factory set and sealed. Batteries will be removed from tester and placed in the shipping case, whenever the tester is not in operation or is being shipped overseas. BATTERIES WILL NOT BE LEFT OR STORED IN THE TESTER. Refer to Section III for instructions. If the batteries are low, a letter "L" will appear in the display. If the batteries are very low, the tester will "cutout". The "L" will appear, but the gauge will not operate. Recharge or replace the batteries (NICAD batteries only-NSN 6140-00-497-0490). Charge the tester overnight when the batteries indicate "L" or low. The battery charger will not damage the batteries by overcharging. A satisfactory program would be to charge the tester over a weekend once or twice a month depending upon use. CAUTION Due to excessive damage caused by battery leakage, only NICAD batteries, NSN 6140-00-4970490, will be used as battery replacement. Quantity of eight (8) each should be ordered. WARNING * Do not attempt charging alkaline batteries. Alkaline batteries are not to be used in the tester. * Do not attempt charging zinc-carbon batteries. zinc-carbon batteries are not to be used in the tester. Shipping Case The shipping case is a fiberglass case with integral, molded foam padding (see Para 3-7 for shipping case maintenance). Reference Standard The reference standard is a separate standard with the fiberglass case. Reference standards are serialized for each tester, however, they are interchangeable between testers. Guideplate The guideplate is cast aluminum. It is entirely adequate for all surfacing and for support of the drill pin during transmission hole preparation. Do not use the plate to remove the drill pin. Drill Pin The standard drill pin is 3/4 inch diameter with a forged head. 1-2. MODES OF OPERATION BACKSCATTER is the technique of placing source on the surface of a flat material. This technique measures only the top 2-inches of soil and is very sensitive to surface roughness or quality of site preparation. TRANSMISSION is the technique of pre-drilling a small hole in the ground and then inserting the radioactive source in the ground via the movable source rod. This technique permits measurement to specific depths to 12- inches and is insensitive to surface roughness. It is very accurate and is the preferred method of measurement for soils. DENSITY is measured by backscatter or transmission. MOISTURE is measured by backscatter only. It is not a transmission phenomenon. The tester uses a separate source in the bottom casting to insure constant 1-2