White’s Electronics Spectra VX3 - Manual (Page 59)

Page 5-6
Spectra VX 3 User’s Guide
Now the signal response starts at zero and still reaches approxi-
mately the same peak point (perhaps resulting in the same final
VDI), but shows some curvature on the way up and on the way
back. Because the SpectraGraph response is taken from the
whole of the signal response and not just the peak, this can
result in a “smearing” effect in the bars, as shown here:
Pay attention to the amount of smearing compared to the depth
and the composite VDI number. If it seems like it might be a
good target that’s just deep, then that is exactly the sort of target
you want to dig.
Trash targets, especially iron, can exhibit significant smear-
ing. To illustrate why, let’s look at the vector response of a bot-
tle cap:
Quarter
-95 +95
0
+83
Bottle
cap
-95 +95
0
+24