TM 5-6635-386-12&P
It is most desirable that the operator maintain a standard
(Moisture and Density Tester (Nuclear Method)
Utilization Log) to record standard counts. DA Form
written down. This is most helpful to the repair shop
5449-R is located at the back of this TM for local
should the tester require repair for some complaint of
reproduction authority.
"drift" or "erratic" counts.
Use DA Form 5449-R
Figure 1-3. Field Data Worksheet
Note that both standard count series produced a normal split of 3 out of 7 inside the limits of + square root of the average.
A split of 2 out/8 in or 4 out/6 in is normal occasionally, provided the usual split is a 3/7 and provided the average standard
count remains within approximately 1/3 square root of the prior series' average.
It is perfectly proper to use the Automatic Standard count
and the manual method trends more towards 4 and 5 out
for daily routine, but it is very desirable that the full
instead of 2 out, the tester is indicating a tendency
evaluation be run periodically to ascertain that your tester
towards erratic counts beyond the normal projected
is running properly, regardless of make or model.
deviation to be expected.
This erratic tendency is likely to come from a dirty high
1-12. WHAT DO POOR RESULTS MEAN?
voltage supply, dirty detector connectors, or a failing
component in the high voltage supply. Simply dusting off
If the tester consistently exhibits a tendency towards a
the supply may eliminate the problems. If this does not
high deviation, that is, the calculator method trends more
work the tester may require repair.
towards the 1.25 end of the spread than the 0.75 end,
1-11