Call me confused...Coil sizes

[Pete in MI]

Have been detecting off and on since the 70s and I had the concept in mind that the larger the coil the deeper it goes but as it goes deeper it loses the smaller things closer to the surface. That being said, I see many who are using the larger coils such as the WOTs over 12 inches...many in the 16 or larger size range and they are using them on beaches.

Now I can understand a larger coil covers a larger area on the swing and beaches sure are large areas...but here is my confusion. I am used to thinking in terms of large coils for relics and cache hunting (i.e. large objects) and not so much for trying to find coins, rings, etc. (i.e. smaller objects - probably closer to the surface too).

From seeing the pics of the coils I am sure they are much lighter to work with...just still thinking more smaller stuff would be missed on a beach than found.

Can someone end my confusion?

 

[NH Bob]

Over the years I have heard from some users and some manufacturers that once you break the 15" mark in coil size your smaller targets such as even some Dimes can be lost. It is in the amount of soil a given coil is made to process.
Example: An 8" coil processes about a Gallon of dirt, where a 12" coil processes 7 gal. of dirt. (examples) So it would be easier to miss a small target the bigger the coil.
Just my thoughts on the subject.

 

[JW]

do not lose much sensitivity to small objects. Also by turning the sensitivity down a little, the coil does not work as hard "processing" the mineralization.

 

[Pete in MI]

I was thinking in terms of the old BFO units for relics, etc. What I failed to consider was "DD" coils and also the Full Band Spectrum of our Minelabs...I think those 2 things might make a big difference over the logic in my mind.
Just a thought.