Keith Southern
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Monte said:It is also true that, generally, a Concentric coil will provide a more consistent, repeatable response, audio and visual display, than will a DD designed coil, and that is also due to the dynamics of the coil design and inconsistent behavior based upon the sweep approach of the DD coils where one direction has the Transmit winding in the lead and the other direction has the Receive winding in a closer relationship with the target on the coil's approach.
Both coil types, Concentric and Double-D might be more responsive out from the edges of the search coil, but that isn't directly associated with the coil design itself, but with the metal detector's circuitry design. I have shown this effect with several low-cost to mid-priced models over the past decade when demonstrating strengths and weaknesses of different search coils and brands of detectors when people have asked how to deal with searching near metal fences and such at sports fields, or metal structures in playgrounds.. It's all a combination of detector circuitry design and search coil design, and not based upon a multi-frequency Vs single-frequency topic.
There are a few very good books out there that help explain more about search coil design and the real EMF that is generated out from a coil. I have seen very good visual descriptions from both Tesoro, in recent years, and Garrett, even back to the early '70s, that displayed how an EMF generally appears. I have also seen and read too many articles and sketches that have shown a 'V' or 'cone-shaped' field being sent out from a search coil and the writer errantly says the detectors send a signal in a 'v' or 'cone' shape. That kind of wrong information gets out there and the average consumer is easily confused or, simply, misguided in how things really work. Worse still, they think that's right because they read it, so they boast the same wrong concept.
I just don't want people to misunderstand a reference to a 'Cone-Shape' EMF or be confused by a size of response based upon multi-frequency vs single-frequency detector design.
What I really would like people to understand is just how well these two brands of detectors work in the real world, and encourage them to get out detecting as often as possible.
Monte
Ringzapper said:You need to be digging all those junk items! I always dig everything these days , i am convinced what i will dig will be a pull tab or other junk item , have a guess what 90% of the time it is junk. The other 10% often surprises me with a good find , like a coin , jewelry , or other good item. I can't do long hunts digging junk though , 1 or 2 hours thats it , day over...
At most of the sites I hunt I dig almost everything I can, if it is not likely-to-be iron junk. I recover pull-tabs, pry-tabs, screw caps, most foil, and a lot of other junk ... if it is a non-ferrous type of trash ... in most applications I hunt in an urban environment. When working the more isolated sites where iron nails are the primary offender, I often hear them but audibly ignore them, unless they are in a very annoying close relationship. Then, after a while, when I am bothered too much and I use only enough Discrimination to just barely reject iron nails. No more than that.Ringzapper said:You need to be digging all those junk items! I always dig everything these days , i am convinced what i will dig will be a pull tab or other junk item , have a guess what 90% of the time it is junk. The other 10% often surprises me with a good find , like a coin , jewelry , or other good item. I can't do long hunts digging junk though , 1 or 2 hours thats it , day over...
And I agree, in some applications, based on the volume of trash or maybe just because you have very limited tome to hunt or limited access to the location, 'Cherry Picking' can still be a rewarding approach. At much older sites, such as railroad depots and sidings, stage stops, and other sites of activity in the 1800's and to about the Depression Era, I use the least Discrimination I can and recover all good and iffy target signals.Flbchbm said:True, however sometimes its nice to just cherry pick. Sometimes, if you dug every signal it would take hours to cover a very small area. Some park areas are so carpeted with signals that you would be better off with a back hoe and a screen.
Huh? I disagree with you on that because the Nokta and Makro detectors are excellent at target separation, with terrific unmasking capabilities. That's why they are my primary-use detectors, because they excel at weeding good targets out of very infested trashy sites.Flbchbm said:The target separation on my Fors CoRe leaves a lot to be desired.
Okay, then I read this part and realized you are not talking about 'Target Separation' in search and response performance, you are making reference to how closely the TID or VDI [size=small](Visual Discrimination Indicator) [/size] numbers are spread-out so s to try and visually classify probable junk targets from possible keepers. Well, it is impossible to be 100% accurate, or sometimes even come close due to the fact that so many unwanted pieces of trash have a VDI numeric read-put that is so close to, or the same as, many of our US coins.Flbchbm said:Nickles and pull tabs are 56-60. Pennies and pop cans or steel bottle caps are 82-84. Hence, the desire to know what the VID is for some common trash items on the Racer. I am sure I am not the only one that is curious. Might be worth upgrading if the Racer 2 has successfully addressed this short-coming.
REPLY:Flbchbm said:You are right, Monte. I mispoke. The Fors CoRe has excellent target separation, probably more limited by the user than the machine. I really appreciate your sharing your knowledge and experience with us.
AN 'ANSWER' THAT IS STILL A 'NON-ANSWER':Flbchbm said:I hope I am not putting you in an awkward spot by asking this question but if you could only have the Fors CoRe or the Racer 2, which would you keep?
Beyonder said:"Can I sweep too slow with the r2 and lose performance or depth?"
If you have to ask this question, then I suggest the Racer 2 isnt for you.
On the Red Racer you can get a signal at a slow sweep speed so I imagine that you'll be fine. If that doesn't work you can switch to all metal and set the isat to a comfortable setting.petew said:And my next question, how slow if a sweep speed is nessesary for deep mode?Can I sweep too slow with the r2 and lose performance or depth?
Beyonder said:"Can I sweep too slow with the r2 and lose performance or depth?"
If you have to ask this question, then I suggest the Racer 2 isnt for you.