Hardrock65 said:
What would be the advantage more depth? I have an MX5 with the stock 9" plus the 6x9 DD and have not had the stock coil on since I got the DD.
Just curious.
You
might get "more depth" over a smaller-size coil, like the Nokta/Makro 4.[size=small]7[/size]X5.[size=small]2[/size] DD. You
might also get a little more coverage on the left-to-right sweep, if the location conditions are favorable and there are not too many closely-located targets.
For me and my general needs, 'depth' isn't as important as being able to hunt in a densely littered site, especially those that about in iron. For ME, I like the 5½X10 DD over the stock 7X11 DD because it weighs less, balances better, and can provide a little improvement in a more sparse-target location. The small '
OOR' coil [size=small](the little Out-of-Round coil)[/size] is what I keep mounted on my Racer full-time because I use it most of the time.
As for the other brand detector and coil choices you have, my personal preference was to use the 6½" round Concentric most of the time, and in more-open, sparser-target locations, the round 9" spider Concentric coil was the better choice for in-the-field performance as well as coverage and depth. I have used the 6X10 DD coils many times, both in-the-field and in seminars and other demonstrations with people and, time-and-again, it didn't perform as well as people thought and didn't match the overall performance and depth of the round 9" Concentric coil.
The Nokta/Makro folks only make Double-D coils for their FORS and Racer models, at least at this time, but I would like to see/have a good working, smaller-size Concentric coil for them ....
IF they could work well with their detector circuitry design. The important thing to consider is
how the detector itself was designed and if, by design, it functions best with a Concentric or DD coil type.
As it is, I am quite pleased with the performance of the FORS CoRe and Racer with their little '
OOR' coil mounted.

Killers in dense trash.
Monte
[size=small]
PS: I'll add my personal preference is coil descriptions. I will type the smaller measurement first and the larger measurement second. When shopping for lumber to build a wall or a deck or ???, I order a 2X4 or a 2X6, and not the other way around. I note that Nokta/Makro refer to their little '
OOR' coil that way, describing it as a 4.[size=small]7[/size]X5.[size=small]2[/size]. So I call a 6X8 SEF, or 5½X10 Nokta/Makro, or 8X9 Tesoro coil they way I believe they ought to be described.[/size]