In Bounty Hunter and Garrett's defence, we were in a drought and the ground was hard packed until three days before I Got my Cibola. It started raining and I didn't go MDing until I got my Cibola and now I'm not as interested in using the other two metal detectors.... Yes, there can be some pronounced differences between very dry ground and very wet ground. Usually ground that is only wet to a portion of a target's depth might not be enough to make a difference, and sometimes can have a negative effect. Once a person realizes some of the weakness of some TID models, and the pleasure of working a good-performing lightweight detector it's tough to go back.
If I took the Bounty Hunter and the Garrett out with the moist ground we have now I would probably get better results.... Possibly. maybe better than they had done before, but I doubt that they would do as well as the Cibola.
The soil conditions around here are very good in most areas. The biggest problem, as I see it, that we have around here is dryness in the summer time. I believe that does effect the depth at which most detectors will go.... Yes, but in addition to the 'dryness/wetness' issue is the matter of how the turn-on-and-go models Ground Balance is set. I haven't checked a Cibola for that in a while, but I know the Garrett's have all had too negative a GB for many of the more mineralized sites I hunt. If you're in mellower ground they might do better.
It is very interesting about how Motion Desc developed, but I was not able to find information about it til now. I did read some info on the engineers who developed it but I was never able to determine what dates were associated with different developments and so on.... George Payne is the guy who made the first good advances in motion discrimination when with Bounty Hunter, and White's was licensed to use their concept until most manufactures started to have their own engineers work up new circuitry.
Those early SPD Red Barron's required a very deliberate whipping speed, and the early White's and Teknetic