Question to Monte

[terry-cola]

Monte, do you think the Omega will reject the tin or iron rounded beer cap as it was shown on the video from the At pro?

 

[Monte]

on beer and soda bottles. I will be working with the AT Pro and Omega and MXT Pro and a couple of other detectors and post the final evaluation results on Saturday, most likely. The first two postings on the ahrps.com Forum were strictly indoor comparisons. I've watched a number of videos attempting to depict what the AT Pro will do with bottle caps, just as I have witnessed and used other detectors with so-called bottle cap identification. Generally, you'll find that some attempts to get better bottle cap ID on direct target sweeps can result in less than wonderful performance on other types of targets.

A couple of examples of detectors that have been a round for a while show some design differences. Take the White's 6000 Di Pro SL or the 6000 Pro XL and renamed XL Pro as well as their XLT. These models, which are basically analog types wand use a four-filter type circuit, do produce a reasonably good "bottle cap reject" response. Naturally, this is usually most effective on bottle caps that are relatively shallow, such as in the upper 3" of the surface, or perhaps to 4" but iffy at that point. Those are typical levels where bottle caps are found.

There are some models which, just by the nature of their design, also handle bottle caps pretty decent, such as the analog-based White's Classic ID or IDX Pro models. They can kick-out or break-up a bit on bottle caps in a somewhat different manner even on a direct sweep.

The Teknetics T2 is another model that features a bottle cap audio circuit in their 3b selection. The main concern I have with iron rejection with the T2 and some other models is that they use a Double-D coil and DD's are generally not that good at discrimination compared with a concentric designed coil. However, and I admit that it took me time to like it, I found the T2 can do a decent job of classifying some bottle caps using the 3b audio. However, it doesn't always get it right, and some desired non-ferrous targets can also produce more inconsistent readouts while being tighter when I use a different audio process choice.

All that said, I will tell you that most of the time, regardless of the make or model detector in hand, I can get the most reliable 'bottle cap' audio and visual classification on the typically shallower caps by employing techniques I have used and taught for about thirty years. depending upon the search coil used and model, and sweep speed I am able to use at a site, I use my "Quick-Out' or "EPR" (Edge Pass Rejection) techniques which will usually produce a low-tone audio if Iron is accepted, or maybe audibly reject the bottle caps if a little iron rejection is used. Also, it will produce an Iron Target ID read-out. Both the rejection or low-Iron tone and visual Iron ID are what we ought to get from those bottle caps.

The AT Pro I was working with the other day did okay in the in-air testing, but I'll do some more in-air and in-ground comparisons this Thursday and Friday.

To conclude I will tell you this. I enjoy using my Omega quite a bit and I don't have any problems classifying or identifying most bottle caps as likely iron targets using the Omega. I won't compare it to any videos because I wasn't present to compare with the same settings and samples, but I can tell you the Omega does quite well.

Oh, if you would like to read and print out a copy of my article on Audio Target Classification, you can view it and download it under Tips & Techniques at the ahrps website. That will explain 'Quick-Out' and 'EPR' techniques.

Monte

 

[TellYaWhut]

Monte have you tried using the 9.75 concentric coil on the T2?? If it works, it might do good with bottle cap rejection. Thanks

 

[terry-cola]

I got what you are saying Monte and I'm going to make sure I visit that page you are telling me for the tips, but on the video, it seems, like a budlight tin or iron bottle cap not alluminum. I guess is more difficult to reject an alluminum bottle cap than an iron or tin coated one. All these with respect to coins. Thank you for your response. By rejecting, I mean, either visually by looking at the screen or by sounding different as in the case with the at pro.

 

[Monte]

I got what you are saying Monte and I'm going to make sure I visit that page you are telling me for the tips, but on the video, it seems, like a budlight tin or iron bottle cap not alluminum.

All of the crimp-on, or modern short-twist on, bottle caps that are of the short, crimp-edge design tend to me ferrous based and are magnetic (they stick to a magnet). It could be iron or the metal nickel or whatever, but they are magnetics-based. The taller caps used on some wine bottle, beer bottles and some other beverage containers are usually made of aluminum. There is a definite difference in how our modern detectors handle them when it comes to discrimination.

I guess is more difficult to reject an alluminum bottle cap than an iron or tin coated one. All these with respect to coins. Thank you for your response. By rejecting, I mean, either visually by looking at the screen or by sounding different as in the case with the at pro.

I think that while there are still some of us "old timers" around who remember the days of TR-Discriminators or the early VLF/TR-Disc. designs, most of the hobbyists today use modern motion-based discriminators. I mean just think of the time lapse. We had TR-Disc. models in the 70's and into the early '80,s, and VLF/TR-Disc. models from the late '70s into the mid-'80s, but motion-based VLF-Discriminate models started in '78, and really flourished by '85.

So, for the past 25 years, a quarter-of-a-century, the predominant detector design offered by every major (or minor) detector manufacturer has brought us a motion-based Discriminate detector. So, what's the difference between a 'traditional' or 'conventional' TR-Discriminator and a Ground Compensating motion Discriminator? The good news is that the motion Discriminators provide us the ability to search without a constant need for a critical coil-to-ground relationship, and they ground mineral signal is ignored or dealt with with ground balance circuitry. Due to the fact that the circuitry is receiving and processing both the ground signal and the target signal, search coil motion is required, but this all provides us with ease of operation and less falsing.

Now, the bad news. While our modern motion Discriminate detectors do give us better ground handling and less falsing from coil-to-ground relationships, and they also usually have audio and/or visual target ID information that the TR-Disc. models didn't, what they do not do well is handle some discrimination when it involves both typical Iron rejection when a targets is man-made with a more conductive shape.

I explain this a bit in the article I mentioned, and I go over it in every seminar I conduct for thirty years now, but a TR-Disc. model has what we can call "true, progressive discrimination." That is, if you were to lay out typical targets encountered when we went coin hunting in order of their conductive properties and in order of rejection from least-conductive and easiest to discriminate up to the highly-conductive big silver dollar, it would look something like this:

Iron Nail .. Bottle Cap .. Small Foil .. Big Foil .. 5

 

[jbow]

Oh, if you would like to read and print out a copy of my article on Audio Target Classification, you can view it and download it under Tips & Techniques at the ahrps website. That will explain 'Quick-Out' and 'EPR' techniques.

Going there now to DL... I wasn't aware of the tips section. I should pay more attention.

edit: Ahh... I had the forum bookmarked instead of the main site.

Julien