DD coil verses concentric

[markg]

Exactly what does the following statement from the field test of the lobo mean?

However, the widescan coil does not discriminate as well as the concentric coils do?

Is it because the DD coil detect a larger path than the concentric coil.

 

[rmptr]

I would suspect so... The concentric should be a more defined search pattern less subject to masking.
HH

 

[JB(MS)]

According to George Payne the reason widescan, or DD, coils don't discriminate as well as concentric coils has to do with the coil windings being different, and also that DD coils have a tendency to shift the phase away from the value of the target. On a concentric coils the transmit winding is a lot larger in diameter than the recieve winding, on DD coils they are the same size. It's pretty much over my head, but George invented darn near every feature on modern metal detectors, inlcuding the phase shift principle that allows ground balance and discrimination, so I'll take his word for it.

 

[SNOWY]

Here's an interesting link re- some coil patents...

So many possible configurations.

http://www.deeptech-bg.com/search_coils.pdf

 

[nick hunter]

It is a well-known fact that DD coils are not that good in discriminating, but they are quieter, or less chatty, in trashy areas. A concentric coil would go about 10% deeper (for the same coil size) but only bang under its center, while the same sized DD would go 90% of the depth of the concentric one, but anywhere under the coil. (conic search pattern vs basin search pattern). I personally prefer DD's with extremely powerful MD's, although I've found out small concentric coils to be more subtle. Question of personal choice and hunting conditions/style.

HH

Nick the Belgian

 

[Scully]

n/t

 

[SNOWY]

There's a link for you to download that PDF I was talking about.