Lorenz 1m double frame coil - how does it work?

[bernte_one]

Hello,

i just want to know how such a double frame coil work
http://www.metaldetectors.de/uk/accessories.htm

i suppose that it are two identical coils
wired parallel, in same direction- means not one transmit and one receive part
the coils have one y splitter which goes to the e-box


or is it wired in serie?

kind regards and thanks for reading and thinking about it

[Ferric Toes]

Hello,

i just want to know how such a double frame coil work
http://www.metaldetectors.de/uk/accessories.htm

i suppose that it are two identical coils
wired parallel, in same direction- means not one transmit and one receive part
the coils have one y splitter which goes to the e-box


or is it wired in serie?

kind regards and thanks for reading and thinking about it

I have used this type of coil to cancel power line noise, which it does very effectively. The lower coil is both transmit and receive just like a standard mono coil. The upper coil is a secondary receiver coil identical to the lower. In the front end amplifier the two receive signals are subtracted, but as metal targets are always closer to the bottom coil there is a good differential signal between the two coils, depending on the spacing. Power line noise gives almost equal pickup in both coils which then subtracts out very effectively. Movement of the coil array in the earth's field also generates equal signals which subtract to zero.

Eric.

[bernte_one]

hello eric,

did you still have this special y connecter

how is it made that the upper coil gets no transmit pulse

seems that the upper coil is only connected to the receive pins from the connector of the e-box

so the lower coil uses only the normal connection for a mono coil

step for step there comes some light into the darkness

thanks till here

[Ferric Toes]

hello eric,

did you still have this special y connecter

how is it made that the upper coil gets no transmit pulse

seems that the upper coil is only connected to the receive pins from the connector of the e-box

so the lower coil uses only the normal connection for a mono coil

step for step there comes some light into the darkness

thanks till here

Hi Bernte,

I don't have a Lorenz coil, but assume that the principle is the same as I used in 1980's for a vehicle mounted detector. I would think that the two cables go into a multi-pin connector where two of the pins are dedicated to the subtracting receiver coil. I used a separate connector for each coil.

Eric.