volpe said:
Is the 7" concentric coil a viable option if one already has the 5" coil that is part of the pro-package? It would seem that as the concentric coil "detects" in a cone shaped pattern under the coil, thus, it seems the area covered is smaller in diameter the deeper the signal reaches.
Yes, I feel the 7" Concentric is a viable option, and is a nice complement to the 5" Double-D coil. The smaller 5" coil is especially useful when hunting a very dense, brushy environment, or for sites with an abundance of potentially masking trash targets in close proximity, especially if the trash is a ferrous-based metal.
As for comparing the functional portion of the EMF, don't be misled that a Concentric coil's effective field is a nice-and-proper 'V' or 'Cone-shape' because it isn't. And also don't be fooled that a Double-D's EMF is like a 'Knife Blade' or 'Wiper' effect to the full extent of the coil's detection depth because that is also not true. If you compare two coils, a Concentric and Double-D, of comparable size, and could see a side view of the functional portion of the EMAF, the Concentric design will taper to more of a 'Cone-shape' whereas the Double-D would taper to more of a Bowl-like shape. That would be a view from the side of the search coil. But the Cone-like shape won't usually be a steep angle from the outer edge to the center-axis point, but usually a bit broader closer to the search coil for two or three inches before it begins to taper.
Also to consider are the typical differences in similar-size coils, and that is that the Concentric designed search coil will usually provide slightly better depth of detection than a DD, and the Target ID will usually be a little tighter. In addition, Concentric coils usually discriminate better when dealing with iron debris than a Double-D design.
volpe said:
OK, but why is it a must have coil, before I invest $150 in the coil and lower rod assembly, I need a good reason to do so, ....I'm married. The link indicates that Kruzer users like the 7" concentric, but no mention of Racer 2 fans. The coils for Racer 2 are compatible with Multi Krusers are they?
1st.. The answer is
NO, the Makro Racer and Racer 2 search coils are
NOT compatible with the Kruzer and Multi-Kruzer. Those models can use the Nokta Impact coil, but the coil cable lengths are usually going to be too short if you stand 6' or taller.
2nd.. Only the original Racer and Racer 2 share the same search coils.
3rd.. If you search a variety of hunt sites with different trash target challenges, you will more than likely notice some of the benefits of using the 7" Concentric search coil. This coil produces much improved audio and especially visual responses when dealing with a dense amount of small rusty tin shards as well as other ferrous and non-ferrous trash.
volpe said:
It seems necessary to overlap multiple times to account for a reduced "detection" area of the cone.
Not really. For hitting on the mid-depth to deeper targets it might help to overlap more, but proper overlapping and coil control are necessary with any type of search coil, including Double-D types. For general-purpose use, I found the 7" Concentric coil for the Racer 2, as well as the one for the Nokta Impact, to provide really comfortable balance and feel and performance to serve as the main-use search coil.
My two must-have favorite search coils for the Racer 2 are the 7" Concentric, and 5" Double-D for trashier and more confined locations.
Monte