AT PRO Coils 9x12 or 8.5x11?

[xmarks73]

I am wondering if anybody has ever revved these two coils against each other. I am not real sure which to go get. Any advise would be appreciated.
Thanks so much.

 

Amazon Forum Fav 👍

A Handbook of Civil War Bullets and Cartridges - Grab it through Amazon!

[GarretDiggingAz]

According to the Garrett site. The 8.5x11 is the DD and the 9x12 is the concentric. It depends on what you're hunting and the soil conditions. The DD works great on mineralized soils, but the concentric one (from Garrett site)
Concentric
The concentric configuration consists of a TX coil and RX coil which are usually circular and arranged as shown at left. The advantage of this configuration is that both the TX and RX coils are wound as large as possible within a given searchcoil diameter. This provides the largest possible detection field and greatest detection depth, making the concentric coil potentially the most sensitive configuration available.

In addition, concentric coils also provide the most symmetrical detection field, allowing ease in pinpointing and consistency in target identification. For these reasons, they are the most commonly used searchcoil and will provide the best overall performance in most environments.

Unfortunately, this configuration is the most susceptible to interference from ground minerals, which results in substantial loss of performance when used over heavily mineralized ground.

Both are good. It just depends on mineralization. If mineralized then DD coil would be best. If soils are neutral then concentric.
Hope this helps.