professor-tones,:
I am about to purchase the 5 Inch Coil monte. I am not an expert on Coils but i wonder why Makro / Nokta did not make the 5 inch a concentric design.
Search coils are an interesting topic all on their own. Size can be very important to accomplish handling different tasks, and the 5" coils from Nokta / Makro work great for getting in and around dense debris, and especially unmasking potentially good 'keepers' that are partially masked, especially by ferrous junk. So the size selection is very useful.
When it comes to the inner search coil configuration, either Concentric or Double-D, then other things come into play. One is the detector manufacturer and the design engineer. Does the manufacturer and/or engineer and/or anyone of importance actually get out metal detecting or are they just detector designers and makers? There's a difference right there regarding the influence behind the detector as a savvy detector operator knows more about the physical design and function of the two types of search coils, and can design a detector that will be able to work well and get the benefits either type might offer. Then you have other people "up-the-line" in some companies who don't look at the actual performance of the detector or even know or understand the differences in design, the EMF's, or the performance the two coil types might offer to know their strengths and weaknesses.
What they do know is numbers, and they look at a bottom line t make $$$ based simply on what they perceive when looking at the competition, and they ask for or instruct a design engineer to actually make a detector with a certain type search coil. Not just the type but also a size or shape coil, and they do it for one reason. They see what the competition is offering and try to match it. Then you can go one step more and actually have not just a sharp engineer who knows how to make stuff that works, but within the brand's system you have some sharp-minded people who actually read Forum discussions or e-mails and conversations and listen to consumers. Knowledgeable people in marketing who don't just look at the other companies, but look and listen to the end-users who have experience and know what they want and, for some applications, what they need. In time, they will hear what it is that the end consumers really want and ask for and do their best, because they are knowledgeable marketing folks, to enhance their product line and provide us, then end-users, with a mor functional array os search coils.
There is one other consideration and that is some makes and models of detectors, by design, just do not work all that well with a Concentric coil or with a Double-D coil from that detector manufacturer. Oh, there is one other thing and that is that in some search coils sizes, such as the very small coils we see in use, On design type can often provide all the functional performance deeded that might not be so different to favor one type over the other. As an example, when you look at the smaller-size coils, Tesoro offered both a 6" DD and Concentric, and with their circuitry design, the Concentric is the clear winner. Garrett offers a small 4½" coil, as did White's for some models, that was also about a 4½" diameter, and they chose a Concentric design, but the folks at FTP made the 5" DD's for most of their detectors for Fisher and Teknetics.
Could there be a major difference in performance between the DD's and Concentrics in that 4½ to 6' diameter size? Possibly, as we can see from the Tesoro detector performance, but for the most part I haven't seen a real pronounced advantage between one type over the other. I have noticed, however, a differences in how they worked based on how the detector's circuitry was designed. From Nokta and Makro products, having used both the 4.7X5.2 DD, which I named an 'OOR' coil for the slightly Out-Of-Round shape, and their round 5" DD to be exceptional in-the-field performers. After over 5 years of enjoying my favorite Nokta / Makro devices, I have been more than just satisfied with the performance from those two DD coils. I wouldn't even be interested in a 5" Concentric, and I happen to be a fan of many Concentric coils, too. But I don't think, in that size range, you would see any real advantage.
rofessor-tones,:
I can honestly say that the 7 inch concentric will "unlock" those nickels AND other jewels that the bigger coils will struggle to give good ID on.[
I am in complete agreement regarding the 7" Concentric. When they worked up a 5" DD or the Impact to improve it's performance in a dense iron nail challenge, the quickly followed up by finishing a 7" Concentra coil which they brought out for the Impact as well as the Racer & Racer 2. They also made a really functional mid-sized Double D elliptical in the open-frame 5X9½, too. For me, depending upon the particular make and model and the sites generally hunted, I think either the round 7" Concentric or elliptical 5X9½ DD make just about excellent choices for a "General-Purpose" search coil. I hardly ever used the 7X11 DD or other coils in their line-up. It's just these two and either the 'OOR' or 5" DD to make a great 2-Coil or 3-Coil outfit.
I do, however, really like the newer round-shaped 11" DD introduced with the Anfibio, and for open-area searches it is the coil I prefer o9n my Simplex+. I just hope they will now make a 5" DD and 7" Concentric for the Simplex to round out a 'perfect' coil-set for it.
Monte
