Why the Fog Lights Analogy on Detector Sensitivity is Flawed

Why the Fog Lights Analogy on Detector Sensitivity is Flawed

A few years ago, when I first started dissecting my detectors (figuratively speaking) to determine how and why they work in an attempt to take more control and get better results Civil War relic hunting, I struggled to understand how sensitivity affected depth.   Finally, I found an article on a forum on sensitivity that made a lot of sense.  It included an analogy that sounded practical, and that I quickly accepted.  Something like:

“Sensitivity levels on your detector are like fog lights.   At the perfect level, you can “see through” the fog.  Too high sensitivity and the fog is illuminated and you can’t see through it.  Too low and you don’t have enough power to see through it.”

I’ve seen this analogy repeated everywhere in different forms for the last few years.     So I detected at the recommended sensitivity levels, either automatic, or otherwise, with no problems.

When I started hunting heavily hunted Civil War sites, I realized quickly that in order to be successful, I was going to have to learn some new detecting techniques, and continually max out the capabilities of the machines I used.  So I started working in a very complex test garden to completely “rebuild my swing”.

Up until that point, I had believed that the detector was actually “finding” stuff.  I was just digging.  I was following my detector around like a puppy hoping it would “give me a good signal”, make a “cha-ching” noise, and instruct me to dig.  And if it didn’t with enough regularity, like most detectorists out there, I thought I needed a new machine that would, preferably the latest, most expensive thing.

I can remember the moment when I “got it”.  The moment that freed my mind from my machine, and changed everything for me.  Working in the test garden, I quickly realized that I could get more depth by cranking up the sensitivity to the highest level that the machine would remain stable.  And I could change frequencies or channels to crank the sensitivity up even more.

The rub was that target identification suffered tremendously, and most really deep targets that I couldn’t detect with my standard or automatic sensitivity just kind of defaulted to nail-like signals.   Deep silver dimes.  Crazy deep Civil War bullets, etc.   I found this was pretty much the norm across all of my machines.  I could detect it, but it didn’t matter because it was discriminated out as iron.  So what good was detecting a target, if the detector couldn’t tell what it was, and discriminated it out like a nail?

This is when I dropped discrimination to hear and see those deep keeper signals.  I’m in my test garden.  I’ve got a silver dime at like 18 inches, and I can hear it.   It is showing a “12” on the F75 and the depth meter is showing deep.  I’ve got a deep nail about two feet away from it for comparative purposes.

With a little work, I developed a technique.  I’d isolate the dime, and do a little  2 or 3 inch “wrist wiggle” swing over it.  And the number would start to jump up or around. 12-12-12- 22-48-12-12-12.

So I took this knowledge out into the field and started digging some crazy deep good stuff.  But I was also digging a lot of falsing deep nails.  So I worked in the test garden again to reduce the number of falsing nails I dug.   Hitting the deep targets at multiple angles helped tremendously.  If it sounds like a nail initially, but is deep, I’d do my wrist wiggle, and if it jumped around, I’d turn 90 degrees and try again.  If it didn’t jump around, it was probably a falsing nail. Not always – as they say, the best discriminator is your shovel.

And then I worked with my headphones to train my ears over time to recognize “thumps” and “scratches” and other auditory clues.  Over time, with more work on Ground Balance and detector specific settings, I was able to keep my sensitivity cranked up so I could reach the “unreachable”, but dropped my falsing nails down to next to none.  The only time I dig falsing nails now is when the site is so hunted out I suspect I’ve got a deep nail, but dig anyway because so few targets remain.  And very often I am surprised with a great find, as targets that are on the extreme outer range of my detectors range sometimes do not give me enough clues to distinguish good from bad.

So my epiphany was this:   The fog lights analogy is built on the idea that the detector makes your dig decisions for you, and discriminates out everything else to save you the noise.   Optimal sensitivity levels are critical for this process, because if you crank your sensitivity up too high, you lose target ID capability, and then your detector just sounds unstable, like random noise, and good items may be inadvertently discriminated out because they do not read correctly.

But without discrimination, it is a whole different ballgame.   I make my own dig decisions, and just use the auditory and visual cues provided by the detector as information to base my decisions on.  And that coupled with a few other techniques is, in a nutshell, how I’m winning hunted hunted out sites, hitting site after site that once produced a ton of relics, but has been hunted hundreds of times and pull lots of good stuff out of it by simply making my own dig decisions instead of letting my detector do it for me.

In the past, the old fog lights paradigm worked fine, and is still fine for beginning and intermediate detectorists, but in 2016 and beyond we are hunting more and more “hunted out” sites.  The technology gets better, and does help get deeper and work better in iron and trash with discrimination and lower sensitivity levels.  I take advantage of such, but regardless of the technology, I can always get much deeper using the techniques above.

Keep in mind hunting in heavy iron is a completely different animal.  I’m talking about hunting good sites where few or no targets remain using traditional settings and methods.

Adapted from Pixabay

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