3x1 coils

[authere]

Hi Eric,
We are having fun exploring your 3x1 coils Eric, i wonder if you could give us some more history on them as they seem to be a very facinating type of coil,we are getting some very strange outcomes from these coils in that no onehas mentioned their differences before and as you were the one to tell us about them i was wondering if you know of there other qualities.

We are thinking that they are the coil of the future ...would you agree with our findings as i have noticed you were reading about them on Doug's forum, but as yet have not made comment on any of it.

Regards Ron

PS: I think i have sitting at home a coil that no one else in the world has come across at least in it's nature, does that interest you!!

 

[Eric Foster]

Hi Ron,

3 x 1 ratio coils goes back many years and have been used in industrial applications more than hobby ones. This is the minimum size for which the pulsed field falls off less quickly with distance, and also gives more rapid and thorough scanning of a large area. Trade off, of course is less accurate pinpointing. It was proposed originally in the 1960's by Claus Colani, who was a German engineer working for a while in Oxford. One application was to find skiers buried in avalanches and coils of an even larger ratio of sides were proposed. Today there are better methods that can be used.

A figure of 8 rectangular winding is interesting because it is noise cancelling too. Not good for coins and rings that are lying flat, as you get two responses, but for nuggets that have some thickness they should work well in areas that are plagued with em noise.

Was this recently that I was reading about them on Doug's Forum? There is so much to read there, that it is easy to forget.

Coils and their variations are always interesting. What does your "special" do?

Eric.