One person
claims 7" on a dime in one State and another
person claims 12" on a dime in another State.
One person hunts a particular site with
Brand-X detector, then, the very next day,
he hunts the exact place again with Brand-Y
detector and finds more good targets, then
touts the Brand-X detector as inferior.
These are very common and misleading occurrences.
A head-to-head comparison is VERY difficult
to perform. Absolutely ALL variables must
be removed if any form of validity is to
be ascertained. The slightest changing variable
can completely void the test. ---
Let's get dirty and come away clean.
A textbook perfect test-garden is a good
start, yet it does not represent the real
world dirt conditions. This includes simplex
and complex test-garden scenarios. The preferred
method for head-to-head comparison takes
place at several different sites with varying
mineralization and with several different
undug, undisturbed targets in their natural
settings.
Let's say you have selected a local park.
You have located several 'items of interest'
and marked their exact pinpoint location
with colored plastic poker chips. You turn
off Brand-X detector and swap it out for
Brand-Y detector. Here is where the difficulty
begins. Was Brand-X detector control panel
settings optimized for each individual
target? Was the level & quality of signal
documented (for comparison) on each
individual target..... or are you ONLY
seeking to find 'detectable' or 'not detectable'
(go/no-go) scenarios to each detector being
tested...... regardless of signal strength/quality?
How high was the coil over the target(s)?
How fast was the coil sweep speed? Are you
aware that one detector may like a fast
sweep speed.... and the other unit resolves
better with a slower sweep speed? Were you
facing the exact same direction when sweeping
the coil over subject target? Was Brand-Y
detector coil sweeping the subject target
one inch further forward or aft of the exact
pinpoint location? Was only one of the units
properly ground balanced? Is this type
of information potentially "interpretive"?
Are you slightly biased more favorably towards
Brand-X detector? Does Brand-Ex detector
come standard with a 10.5" coil and Brand-Z
detector is factory 8" coil equipped? What
is categorized as 'fair' or 'unfair'? When
you went back to the car to swap detectors,
did the nearby local radio station switch
from nighttime 10KW to daytime 50KW transmit
power? Or did the A/C compressor and pool
pump cycle 'on' at the nearby building?
Were your steel-toe'd shoes and steel shovel
a bit closer to the coil of Brand-X whilst
comparing detectors? Is Brand-T detector
more resonant on low conductors (nickels)
and Brand-Z detector more resonant on high
conductors (silver dimes)? Does one
brand detector fall flat on its face in
bad ground, yet it will trump all other
detectors in fairly mineral-free dirt
---- and you only gave it one
chance at one location ----
and came to one final conclusion?
Are you trying to compare Brand-T detector
equipped with a extremely tight electromagnetic
footprint bi-axial elliptical DD coil to
Brand-Z detector with a concentric coplanar
coil? Are you seeking to find which detector
is simply the deepest unit --
or which one presents the best enhanced
adjacent target separation characteristics?
Are you aware that one detector may be superior
at finding coins next to pull-tabs (non-ferrous)
trash and another detector may be superior
at finding those same coins next to nails
(ferrous) trash? Is one person operating
Brand-X unit and a different person operating
Brand-Y unit? Can you see where this might
make a difference? Did you know that you
can mark targets today --- and tomorrow
you may or may not be able to detect these
exact same targets? If tomorrow brings different
humidity, temperature, rain or electrical
interference, a whole new set of parameters
exists. Are you aware that one detector
may find one set of targets and another
detector may find a completely different
set of targets in the same field? Does this
make one unit inferior/superior to another
unit?
This brings up another interesting scenario/phenomenon.
Say a [very small nail] is 6" deep --- and
a silver dime is directly beneath the nail,
one inch deeper -- at a total depth of 7".
In your hands, you have one detector and
two coils; a 5" coil and a 10.5" coil. With
the small coil installed, the 6" deep nail
is a moderate signal strength -- and the
(one inch deeper) 7" deep dime is starting
to "push the depth limits" of the small
coil, yet still within detectable range;
HOWEVER, the dimes signal strength to the
small coil is much weaker than the shallower
nail --- so the detector reports "iron".
A one inch deeper depth to the small coil
is a formidable signal strength reduction.
x-x-x-x-x Now you install the large
10.5" coil. A target at 6" and a target
at 7" is hardly even a difference to the
larger coil --- the field intensity
at 6" & 7" are nearly the same;
HOWEVER, the detector reports "coin" because
the dime has a larger mass as compared to
the [very small nail]. Sometimes this phenomenon
is referred to as the "wrap-around" effect.
So, is this apples-to-apples... head-to-head
comparison? Interpretive it is! In
any case, armed with this knowledge can
prove to be VERY fruitful. The same detector
with different coils may 'light up'
completely different targets in the same
area. Keep that in mind.
As you can see, there are many things that
can alter data resultants. One of the more
common mistakes is to be facing, say West
(270 deg.) while sweeping with Brand-X,
then repeat the same process with Brand-Y
detector in almost exactly the same direction,
nearly due West (say 255 deg.). This slightly
different (15 deg. difference) sweep angle,
in many cases, is just enough of a difference
to invalidate the comparison. A tight footprint
DD coil can highly accentuate this common
occurrence as you rotate your body around
the target. This is also to say that you
may have hunted a parcel of land numerous
times, always walking South to North (facing
North), yet you keep finding more targets.
Maybe a particular target could only be
electromagnetically illuminated when the
coil is passed over the target from a Northwest-to-Southeast
approach angle. One day you are facing (and
walking) North again, but, this particular
time the target is on your Right side of
your sweep (vs. directly in front of you
or slightly to the Left side); hence, your
coil approach angle into the target is finally
the correct angle and - "Bam" you get a
good hit. Upon further examination, you
decide to rotate your body around this specific target
while sweeping --- only to discover that
this particular target is detectable in
a certain window-of-opportunity of body
rotation --- and is undetectable from other
approach angles,,,, possibly due to a co-located
trash target in close proximity to the good
target. You may or may not be able to hear
the culprit trash item, because of masking,
silent masking or your level of discrimination
dialed in to your detector. (If you have
tone ID capabilities, use zero discrimination
for the full intelligence package of existing
dirt scenarios). Depending upon how your
coil approaches into the co-located targets,
dictates how the detector will respond.
Find the right tool for the right job. Detectors
are akin to eye-glasses. There are spectacles
for specific tasks such as; near-sightedness,
far-sightedness, high magnification macro
viewing, long-range zoom viewing, reading
glasses, 3-D viewing, Solar eclipse
viewing, low-light/night-vision viewing,
Sun shades and shades that are specifically
designed for nothing ... except to just
simply look "cool". And detectors
with 'flames' to just simply look ******
,,,,, you know the rest of the story!
All of this information sounds like 'data
overload'. There are many additional
scenarios that can void a head-to-head test.
Sounds discouraging and difficult, doesn't
it? The bottom line is; DO YOUR BEST!
Remove as many of the variables as possible.
If you can have your buddy standing behind
you ,,, handing you detectors and equipment,,,,
whilst you have your feet planted in the
exact same unmovable spot........
chances are your head-to-head testing should generate
valid results --- as sweep angle direction,
temperature, ground moisture content, humidity,
local electromagnetic interference, local
ground mineralization content and other
potential "variables" become "constants".
When you become accustomed to this procedure,,,,,
you will learn that it was not that difficult
after all!!! Your conclusive analysis
may very well present a resultant that is
not in accord with your initial expectations.
Keep an open mind and don't be biased
....and enhanced performance will ensue.
Your increased awareness and intelligence
will 'magically' increase your volume
of "keeper" finds!!!
