Receive signal on Zed coil

Can anyone explain to me why the outer windings of the receiver coils do not pick up a target?

Decent question, requiring a Minelab answer....

slimpickens wrote: Can anyone explain to me why the outer windings of the receiver coils do not pick up a target?

G'day Harry

They do, it just needs to be bigger, the tiny 0.1 and 0.2 bits need to be at the cross over of the windings of the coil and this is why the double blip on the tiny bits.

Put a multi gram bit on the ground and you will notice the edge does pick it up and if you lift the coil and swing over it at a decent height you get a single target signal as all the receive windings are working together.

cheers dave

davsgold wrote:

slimpickens wrote: Can anyone explain to me why the outer windings of the receiver coils do not pick up a target?

G'day Harry

They do, it just needs to be bigger, the tiny 0.1 and 0.2 bits need to be at the cross over of the windings of the coil and this is why the double blip on the tiny bits.

Put a multi gram bit on the ground and you will notice the edge does pick it up and if you lift the coil and swing over it at a decent height you get a single target signal as all the receive windings are working together.

cheers dave

Well there's me problem Dave, I ain't found a multi grammer yet.
But seriously Dave, are you saying the crossover of the transmit and receive coils, because the 2 receive coils don't crossover each other? I can't see why the edge of the coil can't act like a normal mono and be sensitive around the edge.

Hi Slimpickins
The transmit energy on the sides is less than at the transmit coil itself.So if the target is positioned near the outer edge the generated EMF will be less .This means the signal received at the outer edges will be less.
In a mono the transmit is at the edge so EMF is at max as is the receive signal.
Steve

Thanks Steve, I'm beginning to get it.

Quote Deutran "The transmit energy on the sides is less than at the transmit coil itself"
Steve, there is no transmit on the side coils is there? The outer coils are receive coils only.

Well there's me problem Dave, I ain't found a multi grammer yet.

Now hang on a minute here son, no use reaching up a hogs @rse for a ham sandwich till you kill the pig..

Gime the fokenting here.!!
Now watch and learn tiger!!...turn it on like this.....(sound of 7k turning on)...throw the foken yellow ring at it!!...(sound of ring hitting the coil)...run around like an octopus till lunch....(sound of octopus running round.?)....not sure octopuses make a noise?? ...doesn't matter!!!...just wing it. That'll settle it i sh!t you not!!
Now, bunch up small gold found with SDC and present this to the Super D coil with an angry fist......this will fool 7k into thinking you mean business if its unable to find multi gram nugget by its use by date.
Still nothing.???...right you are!!...kick dirt in direction of the coil....not at the coil, because its made of soft plastic and you may damage the skid plate prematurely....not covered by warranty. Actually, you better get down there and wipe the dust off it....dont wanna make it look like its been abused. Not only that, you know and i know dust will cause the electrons in the field generated by the transmit side of the coil to flow in the opposing direction should they be intimidated by incorrectly, or interfered with dust direction flow. Ok, still problematic..  ...shooosh!!....no shoosh...your irritating me while im thinking.
Rightyo!!...go and get me that yellow ring thing I tossed at it earlier......yeah i dont give a toss if its broken, grab both bits and listen carefully to me...place one bit on the ground, and wave the other bit above the coil in the opposite direction to that of my swing pattern. This is an old trick i learnerded when i was in the the NASA space program racing electric box carriers up and down the shuttle ramp.
Now, grab me that broken pick handle while i give the control box a touch up ever so gently, this ought-a take out that erratic feken hum you seem to be having trouble with....(sound of control box being beaten with tree branch, while whats he's name...Chumbly i think.?.. waves the bit of yellow stuff above the coil).

BANG!!!. ..ohh sh!t!!...now look wotya did!!.... . ya done gone and let the smoke out of it.... ...best be sending that off to Minelab me thinks.



PS, was that tomato sauce or mustard you wanted on your ham sandwich.?

slimpickens wrote:Thanks Steve, I'm beginning to get it.

Quote Deutran "The transmit energy on the sides is less than at the transmit coil itself"
Steve, there is no transmit on the side coils is there? The outer coils are receive coils only.

Correct

Thanks Narrawa, at last a scientific explanation. I've been saying to me self all day " where's that sage who goes by the nom de plume *Na rra wa*? He will lead us out of the wilderness" and here you are!  I got the gist of most of it, except the little bit after "Now watch and learn tiger!!..."

Ps. Err Sweet Chilly if you don't mind.

Narrawa

Owen, ya made me day.

Btw, that yella thingy is called a "Fear-right"

I hear that Slim has ordered a special ML tree branch for testing and a voodoo doll if all else fails.

Robert

goldnomad wrote:

I hear that Slim has ordered a special ML tree branch for testing and a voodoo doll if all else fails.

Robert

 I'll try anything Robert. Minelab sent my request form back, asking whose likeness do I want on the ML voodoo doll........ can't make up my mind.

Love it Narrawa!

Narrawa wrote:

Well there's me problem Dave, I ain't found a multi grammer yet.

Now hang on a minute here son, no use reaching up a hogs @rse for a ham sandwich till you kill the pig..

Gime the fokenting here.!!
Now watch and learn tiger!!...turn it on like this.....(sound of 7k turning on)...throw the foken yellow ring at it!!...(sound of ring hitting the coil)...run around like an octopus till lunch....(sound of octopus running round.?)....not sure octopuses make a noise?? ...doesn't matter!!!...just wing it. That'll settle it i sh!t you not!!
Now, bunch up small gold found with SDC and present this to the Super D coil with an angry fist......this will fool 7k into thinking you mean business if its unable to find multi gram nugget by its use by date.
Still nothing.???...right you are!!...kick dirt in direction of the coil....not at the coil, because its made of soft plastic and you may damage the skid plate prematurely....not covered by warranty. Actually, you better get down there and wipe the dust off it....dont wanna make it look like its been abused. Not only that, you know and i know dust will cause the electrons in the field generated by the transmit side of the coil to flow in the opposing direction should they be intimidated by incorrectly, or interfered with dust direction flow. Ok, still problematic..  ...shooosh!!....no shoosh...your irritating me while im thinking.
Rightyo!!...go and get me that yellow ring thing I tossed at it earlier......yeah i dont give a toss if its broken, grab both bits and listen carefully to me...place one bit on the ground, and wave the other bit above the coil in the opposite direction to that of my swing pattern. This is an old trick i learnerded when i was in the the NASA space program racing electric box carriers up and down the shuttle ramp.
Now, grab me that broken pick handle while i give the control box a touch up ever so gently, this ought-a take out that erratic feken hum you seem to be having trouble with....(sound of control box being beaten with tree branch, while whats he's name...Chumbly i think.?.. waves the bit of yellow stuff above the coil).

BANG!!!. ..ohh sh!t!!...now look wotya did!!.... . ya done gone and let the smoke out of it.... ...best be sending that off to Minelab me thinks.



PS, was that tomato sauce or mustard you wanted on your ham sandwich.?

SPOT ON!

A PI mono coil is only sensitive to small bits at the circumference where the field is strongest. This is also where the distance to and from the nugget is shortest, it obviously can't transmit to a small nugget from one side of a mono and receive from the other side because the distance to and from the nugget would be too large, ie, at least the coil diameter, which would be very large for a 20" mono!!!  

A DD transmits from one coil and receives from the other and the only point equivalent to the mono example is at the so-called "blade" where the two coils overlap, ie, the shortest distance to and from a small nugget is from the inner edge of the transmit coil to the nugget and back to the inner edge of the receive coil. The distance from the outer edge of the TX coil to the nugget and back to the outer or inner edge of the RX coil is obviously much greater. From this it should be rather easy to picture what happens with a DOD coil.

Although I think Narrower's Nararah Old S's Owen's description is probably better.

Thanks Robby, it's all starting to make sense now.
Professor Narawa's "White paper" on this subject should be put on Minelab's Official Web site so it can benefit all mankind. (Or at least make their day.)

slimpickens wrote:Thanks Robby, it's all starting to make sense now.
Professor Narawa's  "White paper" on this subject should be put on Minelab's Official Web site so it can benefit all mankind. (Or at least make their day.)    

I have already forwarded it to Minelab and they have a team of translators working on it as we speak.
They believe there is a hidden message in: "dust will cause the electrons in the field generated by the transmit side of the coil to flow in the opposing direction should they be intimidated by incorrectly, or interfered with dust direction flow".
 

Let these electromechanical implements know who's boss right from the get go i tell ya!!. Got a mate who held his 4500 under water till it said uncle...ay?....he rung its neck good and proper on their first date. That b@stard of a detector thought it was going to a good home.     Like a wayward child who has never felt the slapping from a stern hand, the want to stray of the strait and narrow will never be processed by its CPU ever again....it simply does not compute. However, it shy's a tad when its raining im told.  

I used mine to fell a tree in the GT due to its audio going all crackly like not long after its birth.....it dare not stutter now when pronunciation is required to be nothing short of perfection. In fact, its become a master in auditory. Any imperfection in the quality delivered from the processing stage of the electronics is recalculated, re-calibrated, regurgitated, reorganized and delivered to my ears in the same way as God himself calls upon me for guidance.  
However, i noticed a tree up-root its self once when a leant the detector upon it, while i prepared to take a scheisse.

No point wrapping them in cotton wool folks, beat the BS clean out of them while their young or you'll be sorry i sh!t you not!!.

I vote Narrawa for the new CEO of minelab......

That was bloody hilarious. I'm going to try all the suggestions and perhaps she'll yield to our demands.