Zero Voltage Transmission (ZVT)

[Reg]

Hotrock,

 

Please learn the difference between a coil of wire used as a transmit or a receive winding and an antenna.  The windings in a coil act much like a transformer, which can have different polarities on the secondary.  In the case of a metal detector coil, the tx winding is the primary and the receive winding(s) are the secondary. 

 

This idea is not the same as a set of bunny floppers you used to use on TV's. 

 

Changing the output polarity of any receive winding on a DD coil or the DOD design can be reversed by simply flipping the secondary winding.  It works no matter how hard you try to convince the unknowing it doesn't. 

 

Now, I have wasted enough time on this trivial issue.

 

Reg

[Hotrock]

  Ok, then let us agree to disagree because of our understanding of the science and physics behind it is different. Since you can not explain how a coil wound on the base or in the middle of a TV rabbit ear antenna works, we are wasting time discussing how a metal detector's antenna coil works. Another example is a center load COIL on a CB antenna.

 

  "The windings in a coil act much like a transformer, which can have different polarities on the secondary." TRUE

  "In the case of a metal detector coil, the tx winding is the primary and the reiceive winding(s) are the secondary." FALSE. Can't be a transformer unless the coils are coupled. Primary and secondary is meaningless unless they are coupled.

 

If you are determine to argue that the TX coil and the RX coil forms a transformer, then what is the coupling coefficient value?

 

To understand how antennas coils work, one needs to take an electro magnetic course that discusses antenna configuration application.

[Steve Herschbach]

Come on guys, we are here:

A. To have fun

B. To educate others in language understandable to the layman

Hotrock, Reg Sniff makes his own metal detectors, he winds his own coils. He is well respected by many in the industry. I would hate to have him leave the forum.

[Hotrock]

 Your right Steve. I would like to thank Reg and commend him for helping others in our hobby.  

[El Dorado]

I have a headache now

[Reg]

Eldorado,

 

A metal detector coil isn't an "antenna" even though many people refer to it as such.  Here is an interesting link to the basics of a detector coil in simple terms. 

 

http://www.geotech1.com/pages/metdet/info/coils.pdf

 

Here is an interesting bit of history. 

 

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

 

As for the rest of the rest, well, Mrs. Brown has a perfect response she learned in elocution lessons and that is, "That's Nice".

 

Reg

[Hotrock]

Great article Reg.  The term I was using, TX antenna coil and RX antenna coil was applied to incorrectly as far as metal detectors are concerned. The article expained that very well. The correct term used should be transmit coil or receive coil, and leave the antenna part out of it, which you did state. In this case, they do act like transformers, and I was wrong.