Answer to Uncle Willy: "Monte, is that what you called "edge pass discrimination" or something similar to that?"

[Monte]

Sorry this was delayed, but I've either been out detecting, doing research, or dealing with some more evaluations. This was your response to my reply about two pages back. The discussion was on dealing with those pesky bottle caps.

The article includes several typical tasks we can use, but Audio Target Classification, which is printable under the Tips & Techniques section of the ahrps.org website. I coined the terms 'Quick-Out' and 'E.P.R.' actually earlier than 1981 but have used them in seminars and other instruction since then. E.P.R. stands for Edge-Pass Rejection and has been very useful for decades with the modern motion discriminators.

We do know that a Double-D coil design is often not as good at discrimination as a Concentric design, but that's partly due to the fact that near-proximity targets to a DD (within maybe 3" or so

 

[Uncle Willy]

Thanks Monte. No sweat, I figured you were busy or out beeping. I couldn't remember that term except that it was "edge pass" something. Wonder when Don designed the DD if he knew he had incorporated these little quirks. Those overlapping spines of the D windings do present a problem at times and you're right, discrimination with a DD ain't all that spiffy some times. Hope you're doing well and finding your share of goodies. Whadda ya think of this new AT PRO.

Bill

 

[metalhead]

That's right! I forgot about that. "Don Dykstra" invented the "DD" or widescan search coil! I'm glad he did! My preferred search coils are all "DD"
Happy Hunting!

 

[Uncle Willy]

Yeah he done the world of detecting a real favor with his idea. I used Compass for many years and they had his coil installed.

Bill

 

[Monte]

Thanks Monte. No sweat, I figured you were busy or out beeping. I couldn't remember that term except that it was "edge pass" something.

It's been a very useful technique to deal with iron junk, especially, and it's all thanks to our "modern" motion-based discrimination. Well, not really so 'modern' since motion-Disc. (VLF-Disc.) has been around now for over 31 years. Working with the first (Bounty Hunter Red Baron in the last '70s) and the White's and on to the quick-response models (Fisher 1260-X and Tesoro Inca in '82 and '83) I found that to be the best way to tackle those blasted bottle caps that were much easier for the old, 'traditional' TR-Disc. models to handle.

Wonder when Don designed the DD if he knew he had incorporated these little quirks. Those overlapping spines of the D windings do present a problem at times and you're right, discrimination with a DD ain't all that spiffy some times.

He had a good concept to work with metal detectors, and when the three guys formed Compass that's what they used in those early TR's. But the TR-s and TR-Disc. models, even though they had the overlapped field present, didn't face the challenges that we do with motion Discriminators. In my seminars I try to have a TR-Disc. model on hand, if there's one around, to demonstrate the strengths and weaknesses we got when the added the ground cancelling and Discrimination components, and the biggest nuisance was them trying to knock out some iron, especially odd-shaped stuff like bottle caps and small rusty tin, etc.

Hope you're doing well and finding your share of goodies. Whadda ya think of this new AT PRO.

I'm mending, but as yo know, this getting older and falling apart stuff sure cuts in on the getting full enjoyment out of detecting. The giddy-down to dig isn't too bad, but the giddy-up part's a different matter. I've been out a bit this month, when we've had some dry spells, but only a few of the large grassy areas are absorbing all that rain water so that they aren't sloppy and soggy. No great finds this month. I only have one silver ring and one gold ear clip, but no silver coins.

I wrote up some AT Pro evaluation on the ahrps.org website, with the early posts on 12/23 & 24, and wrapped up the initial evaluation with a post on 1/14. I have used it a bit more since then, but they were borrowed units. All cars have wheels and tires and engines, and even though somebody came out with it first it's not such a bad thing that it was copied by other auto makers. So goes the world of innovation with metal detectors, too.

I like the fact that Garrett Metal Detectors incorporated a quick auto-balance (Fast-Grab and Ground Grab on competitors units) that works in the Discriminate mode. Also, they added manual GB in the Disc. mode. Something many of us have wanted to see for a long time, and that brings them into competition with the Teknetics, Fisher and White's models that have been providing those features for a while now. They also went with a broad-range Iron adjust Discrimination (rather than notch segment rejection) which they have had on their Scorpion Gold Stinger, but White's and Fisher and Teknetics are three that have offered it all along. Again, they stepped things up a bit in competition.

They now provide a model with a numeric digital number (VDI or Visual Discrimination Indicator) as has been used on other brands for quite some time. Also, while I still usually prefer a good concentric coil, they now have a very functions and light-weight Double-D coil that feels good and works well. The AT Pro has a couple of other nice features, and one I like is the ability to select the STD (standard audio or saturated audio that they have been using) or the PRO (Proportional or modulated audio) audio options which lets someone benefit from both saturated or modulated target responses with a quick function change. There are times when both have their benefits, especially for those who are transitioning from typical Garrett style or other saturated audio detectors to the more versatile modulated response which provide a lot more target signature information.

I also like the 'Zero' setting as I find that it is a true all metal accept type and not just a label with a not quite low-enough discriminate setting. Naturally, there isn't a perfect detector on the market, and after the past week of using a good assortment again, including the AT Pro, I am narrowing down what models I want to have on hand to travel with me on a regular basis. Some just feel better than others. Some work better in iron trash than others. Some get better depth, in clean areas, than others, and some have a nice smaller-size coil that also works well in iron infested sites better than others. It's a challenge to try and limit yourself to 2 or 3 detectors that will ride along on the back seat, with accessory search coils, and be ready for a wide range of hunting environments.

Perhaps, when the GMD folks target a more traditional land-based model and work through some quirks they have now, I might add a new Garrett model to come along on my travels. I don't wade or go out in the water so a submersible unit isn't on my list. I also prefer to stay dry and do research than go hunt in the rain. Aging eyes means dinky numbers are more difficult to see, especially on that grayish background (as you noted elsewhere), and I would like a longer upper 'S' rod for better comfort and control and balance. I prefer my SunRay Pro Gold or Killer B Wasp headphones and need a 'normal' headphone jack without having to pay for modification, and I like to change search coils from time-to-time and having an easily handled, normal connector in a location that doesn't challenge old arthritic fingers would be nice.

I also don't like to stretch my headphone cables a lot, especially off to the right side of the control housing since I am right-handed, and I really like the cable to be more out-of-the-way. That's why I like the rear-jack location on most of the White's models, the Teknetics T2, Fisher F-75 and the GTI, GTP and GTAx series models from Garrett. I hope they address that in some future offerings to step things up for more of us typical land-hunters. Better balance (upper rod length), larger VDI numbers, easier/handier coil connections, better headphone jack location, and maybe for those of us who are more avid, give back a regular All Metal mode with Threshold adjustment. You know, a truly versatile detector. Overall, I like what they have done with the good features added and the performance. The AT Pro isn't the deepest detecting unit, but it's competitive, and just has a few quirks that caused me to line it out from my shopping list.

I hope you're able to get out and do some detecting.

Monte