Bob Sickler..a Guest Post

You’ve heard me talk about Bob Sickler quite often here, and I am proud to say I conned him into writing a guest post. Bob is the author of “The Detectorist” and was responsible for many articles and fields tests over the years for Western & Eastern Treasures.   Hopefully he will consider doing more writing. His insight and technical knowledge about all things treasure hunting has been sorely missed.  Thanks Bob!

Bob Sickler

Bob Sickler




Robert H. Sickler

OK, the title is obviously a deliberate play on the accompanying photo, but it’s there to later drive home a point. As a premise, I’d like to acknowledge that  there has been some general sentiment lately that current metal detectors are just a rehash of older technology. I think a second look is in order.

Yes, metal detection is still based on the original principle of induction balance, but metal detector circuits today are engaging the digital age with some  subtle muscle. Ever since ground rejecting motion technology endeared itself to metal detector discrimination, there has been one little problem… The speed at  which the detector recovers from a target rejection to avail itself to another desirable target in close proximity. The earliest motion discriminators required a very fast searchcoil sweep speed to initiate the ground filtration process.  This caused a misrepresentation in operator perceived response location.  As analog circuits progressed, the sweep speed has come down to what could be called normal or reasonable… A speed which is more conducive to careful searching and pinpointing, amen.

Having started metal detecting 45 years ago, my transition into the digital world has been slow because my musician’s ears are still more at home with the tone of analog signal amplification. I’ve tried a few new digital based metal detectors only to be turned off by the character of the target audio and the annoying crispy rapid recovery staccato response.

I hunt mostly private yards and abandoned cellar holes from the 18th and 19th centuries. These locations by default are always littered with nails from the once standing structure. Many of these old homes became flat after a devastating fire and were abandoned thereafter. If you have ever burned a  pile of lumber with nails still in it, you’ll know exactly what hunting around one of these old cellar holes is like. I got to thinking about the rapid annoying response of the digital detectors again and the fact these circuits recover way quicker than the old analog detectors did.  Fact is the older metal  detectors operated with a threshold audio, and you could actually hear how many nails were present at any given site by the duration of the rejection “null” in threshold. Too many nails and the detector stays in the null so strong you could pass over a desirable target and hear only a “click” of an audio indication and possibly walk on by!

I’ll make no secret of my history with Garrett detectors.  I used the “Groundhog” for many years in my early days and it still holds the unbroken record of  my best silver coin found.  When Garrett first came out with the AT-Pro, I still wasn’t sold on digital detectors yet, but my loyalty to the brand and the features of the detector coaxed me into making a purchase.  Here’s a few things that I found immediately attractive about this detector…

Personally I like the idea of being able to read the conductive properties of any metal target in a numerical format.  I also like an active indicator of where those numbers fall in the ascending  target conductive spectrum. The AT-Pro goes a step further and offers the operator the ability to fine tune what level of ferrous rejection is possible, thus preventing larger ferrous targets from totally masking out smaller, higher conductive targets.  I like a synchronous depth reading scale that operates full time, even in the discriminate mode. I also like target ID tones and pinpointing audio that are modulated in terms of target depth and size as well. STOP!  Without turning  this into a full Garrett review, I’d just like to conclude by saying there are a lot of excellent features in an intuitive, lightweight interface that fits my style of hunting for a reasonable price tag.

As for this story, the biggest attribute is the detector’s ability to hunt concentrated ferrous and recover itself quickly to uncover items other detectors sometimes mask out.  It’s also comforting to know you can still keep hunting in drenching rain on a promising location and not have to  run for cover in fear of destroying your investment. Just coming home from a muddy day and taking a hose to the entire detector without that same fear is truly icing on the cake. Ironically, the digital audio on this detector is very close to my old “Groundhog” which is a major comfort for me.  Nothing better than proof in the field though…

Last weekend I contacted a neighbor about getting permission to hunt his mid 1800’s property.  His answer was a welcomed “yes”. Coincidentally, he was about  to contact me with a request to find a gold ring he lost in his garden 6 months ago. The ring had huge sentimental value because it was made from gold in his  father’s ring. I called my hunting partner to share in the hunt and it was a good opportunity to test out the AT-Pro at target separation. Ironically, I had hunted  the front lawn of my neighbor’s home using my old “Groundhog” when my previous neighbor owned it back in the 1970’s. A few “Wheat” pennies and a silver dime were  found at moderate depths, but my guess is the oldest coins are still a lot deeper. Why is another dissertation unto itself!

We started by taking ID readings from a gold ring very similar in size and gold content. We were shown the general area to search and while I was explaining to my neighbor how the detectors worked, my partner was already hunting the garden. Within minutes he called me over to get a reading and it was very close in conductivity to the reference readings, but the depth was indicating 8″ on both our detectors… He dug carefully while I was still conversing with my neighbor.  My partner walked quickly passed me with a grin on his face toward my neighbor and sure enough he found the ring buried in loose dirt only an inch deep, but on edge! (Be careful about a “deeper is always better” hunting mentality.) The look on my neighbor’s face was priceless. I was envious of my partner’s accomplishment. This is a truly great thing we detectorists do for others. I only wish our detractor’s could know all the great unselfish deeds that go unrecorded.

Our attention then turned to hunting the property front. Wow, the house still stood and there were intense ferrous signals all around us! I wasn’t more than  five minutes in the swing when I got a mixed readout of numbers in the 80’s and 30’s with mixed high and low tones. The AT-Pro processed target audio on both levels with great speed. The pinpointed signal was a little wide compared to other coins found on other outings, but a manual reduction in signal strength on the 11″ 2D coil had me cutting a neat plug. Plug folded back (and a smile on my face) there lay a shining example of the last year for silver quarters.  It was just  under the plug depth of about 4 inches which validated the accurate depth reading I was getting beforehand!  Elated, but not totally satisfied, I interrogated the  hole with my handheld pinpointer and unearthed a rusted utility knife blade not far from where the quarter resided.  Between the two of us, we removed a lot more rusted targets, but no more coins in the front yard. I guess I did a good job with the elder Garrett long ago, but I’m convinced I missed a good-sized, fairly shallow silver coin because of rusted steel in the hole.


In conclusion, If your hunt sites are littered with rusted ferrous targets, re-hunt them with one of the newer high speed digital detectors, you might just find more in your own footsteps!

P.S. You can thank or dislike my dear friend Dick Stout for schmoozing and cajoling me into writing such a lengthy piece from self-imposed exile…



Neil McElroy, my whacked out friend in the great Northwest keeps reminding me to keep an eye out for mismatched dollar bills.  His recent Facebook post…

“You might remember that I found a very rare 2006 $1 star note ERROR a few months back.  Just today one of my friends found a similar note!  Keep an eye out for 2006 series $1.00 with a star at the end of the serial number and the letter “B” at the beginning ~ some were printed in error with mismatched serial numbers ~ the serial number on the left starts with a “O” (zero), and the serial number on the right starts with a “2”.  I sold the one I found for $400.00!!  Not bad for a measly dollar out of my  pocket change!


Hmm. not bad at all!



For all you folks who have a detector, digger, pouch, pinpointer, knee pads, drop cloth, camo outfit, and camera….you overlooked something!  Check THIS out!

I must say it’s one more thing yours truly doesn’t need or want…




Filed under Metal Detecting

5 responses to “Bob Sickler..a Guest Post

  1. I love articles like this! Also, I love the AT-Pro, but the E-trac in two-tone ferrous with a 6″ coil offers brings this to an entirely different level in nail-blankets.. You get informational threshold, independent ferrous non-ferrous tones and conductivity estimates with near instant recovery time. If you’re willing to sweep slowly, you can pull a 5″ silver coin in between two rusted nails on the surface laying 3″ apart because you get a grunt-ping-grunt signal every time. I know other machines can be made to do some of this, but I’ve never seen one perform at that level at a homestead rust / iron scatter.

  2. Now, if that had been a sheep, I’d be seriously worried! Anyway, with Mexican beans who needs a duck call?

  3. Bob Sickler

    Hi Scott… You’ll be pleased to know my other detector is the E-Trac! You are correct about its capability in nails. I normally use Minelab’s stock Coin program which I modify slightly combined with the 11″ Pro loop. Amazingly enough I pull good targets from nails around cellar holes routinely. Some very deep. The trick is how to listen for the mixed high pitch and having the all-metal pinpoint mode set to “Sizing”. One such feat was an enlisted man’s Civil War chinstrap slide from a hole with quite a few small rusted square lath nails… No interface to add a photo here, otherwise I would. My aversion to two-tone audio methods is the racket of noise one gets. Even the AT-Pro can be made to operate with low/high pitches without rejection by using the “Iron Audio” feature, but I’m more comfortable with the speed both detectors recover at from rejection for now. For those who can tolerate the noise, your method is a good one nonetheless.

  4. Cool article, thanks for sharing!

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