can this be done

[strike it rich]

Hi first things first I have a limited and I do mean limited knowledge of metal detectors. But could this be done a cover for the coil that channels the waves into a narrow passage of ever drecreasing tubes ending with a very small concise point. I think this would have the effect of amifying the waves in to a very small but powerful point what do you think

[khouse]

I think in theory it could work slightly. But I think there would be no usefull velocity through the tubes or venturi. Are you trying to use the energy to blow around the sand to recover finds?

[gallileo60]

Seems like you could make a sheild for the top and make the coils directional..On radio there are directional antennas..On a detector you can detect off the top of the coil just as easy as the bottom, if you could somehow direct ALL the energy down instead of letting some of it go up, you could in theory increase dectecting depth......Wonder if any research has been done in this area?

[khouse]

I see what you were saying now. I was on another "wave length"

[Carl-NC]

Can't do any of this with a metal detector. A detector coil is not an antenna, it is a transformer. Frequencies are way too low to use directional techniques.

- Carl

[gallileo60]

Can't do any of this with a metal detector. A detector coil is not an antenna, it is a transformer. Frequencies are way too low to use directional techniques.

- Carl

Hi Carl, im not so sure about what you wrote...You can have directional arrays with almost any freq, the question is, is it worth the trouble...I was under the impression that you had a transmit coil, and a recieve coil..Now I have made many loop (coil) antennas over the years for my ham radios, and shortwave, longwave setups...Even if it is a transformer as you are saying, it is still radiating RF energy in a up, down pattern, seems like you could reduce the amount of radiation from the top of the coil, and make it push down harder so to speak.....Anyway interesting subject, but im sure the smart guys have thought of all this long ago, and I guess it is impractical..Look forward to hearing from you, Tom