IB Rx coil at Tx off

[green]

Another try subtracting no target recording from target recording. Nuggets and #8 lead shot.
(nuggets) https://www.geotech1.com/forums/atta...2&d=1547586775

[green]

Some distance measurements. Target distance was adjusted for about 40mV peak(differentiator out)when removing target from coil(#8 shot only 35mV peak, 20mm minimum distance). Threshold could be adjusted for 20mV which would add 10 to 15mm distance(increasing distance about 13mm halves signal for a 133mm coil).

My detector circuit lights a led when signal exceeds threshold. Tried nugget e(led flashed 5 times in row at 35mm) sometimes at 40mm. #8 shot 5 times in row at 30mm. Threshold was adjusted for no noise flashes when no target.

[6666]

Charted nuggets with my TRT tester in previous graph. Log amplifier is a little slow for some of the nuggets. Charted d and e with the detector circuit I've been using with smaller coil(48mm fig8 solenoid wound), subtracting no target recording from target recording. Nuggets in similar location, probably not exact.

Thanks Green thats very interesting with the 48mm coil, you say these nugs are #8 mesh, what size is that measured roughly ?

[green]

Thanks Green thats very interesting with the 48mm coil, you say these nugs are #8 mesh, what size is that measured roughly ?

https://www.geotech1.com/forums/atta...2&d=1547586775 I ordered 1gram of 8mesh nuggets and that is what I received(7nuggets total)picture was taken on paper with 1/4inch squares(little hard for me to see). #8 shot is about .09inches, lot smaller than the nuggets but one of the nuggets is very close with signal and TC.

[green]

Thanks Green thats very interesting with the 48mm coil, you say these nugs are #8 mesh, what size is that measured roughly ?

https://www.detectorprospector.com/f...gget-mesh-size

[green]

Watched a video detecting a can at a couple meters. Looked like a rusty can larger than a coke can. Wondered how steel can compares with aluminum coke can. Charted three different cans. Aluminum can has higher TC. The steel cans had higher start signal(greater distance for same start signal at 5us).

[green]

Charted target distance vs integrator out(LSD=.1mV) for the 133mm fig8 and 300mm fig8 coils I'm trying to finish. Folded a piece of regular strength aluminum foil 4x4inches twice for a target 2x2inches 4layers. Wanted a target that would give a measurable signal at a distance near 3times the Rx coil diameter. Calculated is something I did awhile back with HyperPhysics. Think coil diameter is mean diameter for a mono coil. My coil measurement is ID(133mm coil is 143 mean, 300mm coil is 316mm mean).

[Mr.Jaick]

I really need a drawing to fully understand how things are connected. But a Figure-8 RX needs to have each coil individually dampened because they tend to talk to each other. Here is how I do it in a walk-thru design:

[ATTACH]50367[/ATTACH]

Sounds similar to what you describe except for the damping R's. The Rin's become the feedforward element in an inverting opamp.

Carl can I make Rin's = 0 ohm and connect to the input of a Non-inverting Amp, with a Rd going to ground? or possibly no Rd to the ground at Amp input, of course, keeping the individual Rd's in place for each coil.
just trying to reduce the amplifier's current noise effect.

[Carl-NC]

Maybe something like this:

[Mr.Jaick]

Maybe something like this:

This will 100% work, I was wondering how the coils will react if connecting the coils output together without the Rin's, like paralleling them.

couldn't see your reply's notification on my profile, had to find the thread to check.

[pechkata]

To work very well.
I'm thinking of applying it to Carl's Bipolar.

20 years ago I made this project.

[GeoMax]

To work very well.
I'm thinking of applying it to Carl's Bipolar.

20 years ago I made this project.

Hi Pechkata,
what was the name of the PI detector that you made 20 years ago? Maybe Rado or Viber? Do you have maybe a better picture of the schematic.

Thanks...

[pechkata]

Hello GeoMax
Yes Rado.
All the developments are in the trash - that's all I have.

[pechkata]

It's similar to these schemes.

[GeoMax]

Hi Pechkata,

thanks... that's enough for me. When I looked at your first posted schematic, it looked familiar. But I couldn't figure out which detector it was. Now it's clearer that it's similar to the Garrett detector.