Place tester on prepared site so that the source
tube hole is positioned reasonably close to the hole in the
surface to be tested.
Standing slightly behind the tester with your feet
placed comfortably apart, flex your knees and bend your
body slightly forward above the waist.
Brace your right elbow on your right knee,
grasping the cast lip of the tester with the fingers of your
Put your left hand on the source tube handle.
Allowing the left edge of the tester to remain in
contact with the surface, lift the right edge of the tester
two to four inches above the surface.
Release the spring lock on the source tube
handle with your left thumb and push the source tube
down approximately 2 inches.
Peeking over the front edge until you just see the
end of the source tube, lower the right side of the tester
and guide the source tube into the hole in the prepared
Lower the source tube to the desired depth.
1-20. TAKE A NUCLEAR READING ON SITE
Once the site is prepared, a standard count is available,
and the tester seated, a field count can be obtained.
No advantage is gained from repeating a count on
exactly the same site. It is permissible to rotate the
tester 900 or more on a site to obtain two views of the
location, but there is nothing to be gained from taking
more than one count without at least moving the tester.
It would be better to move the tester to another site
nearby for the second count in order to obtain a better
representative sample of the overall project.
Reviewing paragraph 1-9 and applying these statistical
factors to the tester readings, we will observe that:
The tester will not count exactly the same two
times in a row except by coincidence.
This count variation is a function of the random
This will obviously produce a predictable error in
the final result of PCF values.
The error, identified as "Precision" can be
charted as follows: (1 minute counts)
This error is the testers repeatability. The final accuracy
obtained on the site is also a function of how accurately
the factory calibrated the tester and how carefully the
operator chose and prepared his site.
The value of the final result is also a function of how
representative of the overall project the selected site is.
Precision is also influenced by the selection of time
period on the Operations Touchkeys:
Select the time touchkey which will produce the desired
precision versus time available for the test
1-21. FIELD COUNTS AND TRANSMISSION
Site is prepared, standard count recorded
Seat tester firmly.
Release source handle trigger and lower source
to BS or AC position as desired.
Press desired Operations Touchkey.