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the deepest pi there is
- Thread starter JM
- Start date
Wantmoregold
New member
Have Air-Tested a US nickel with a GP3000 and ML 8" mono coil registering with a High/Low(wee/woo) signal at 14".
Eric posted some Air-Tests using a nickel and his GS5 with a CT 14" mono coil for 16" and with a 6" mono coil for 10".
Brian.
Eric posted some Air-Tests using a nickel and his GS5 with a CT 14" mono coil for 16" and with a 6" mono coil for 10".
Brian.
Wantmoregold
I remember Eric posted those GS5 nickel depths a while back on the original GS5. However they will not be valid on the new upgraded GS5.My upgraded GS5 is in transit from the UK so I can't comment on nickel depths of the new GS5.
According to Eric among other things the new GS5 has a new range control. The new range control doubles the amplification in the receiver. According to Eric the mid range position on the upgraded version corresponds to the maximum range on the old GS5. This should mean more depth.
Perhaps I can post some depth tests on the upgrade in the future. This may not be directly correlative with previous tests as I will be using NF and Coiltex elli coils(better for IDing different metal types).
HH
George
I remember Eric posted those GS5 nickel depths a while back on the original GS5. However they will not be valid on the new upgraded GS5.My upgraded GS5 is in transit from the UK so I can't comment on nickel depths of the new GS5.
According to Eric among other things the new GS5 has a new range control. The new range control doubles the amplification in the receiver. According to Eric the mid range position on the upgraded version corresponds to the maximum range on the old GS5. This should mean more depth.
Perhaps I can post some depth tests on the upgrade in the future. This may not be directly correlative with previous tests as I will be using NF and Coiltex elli coils(better for IDing different metal types).
HH
George
Hi George
Hope your unit arrives soon. Sorry for all the delay.
On the depth thing, I don't remember the range that the other fellow made a post about from Eric. It must have been a while back, plus what one hears at one way, another may or may not hear at all. Eric uses a set of headphones just plugged in, but laying on the bench. Thats certainly good for a few inch's less than having to listen when there on your head.
JM's was about right, there's not much staying up with the Foster units overall.
Hope your unit arrives soon. Sorry for all the delay.
On the depth thing, I don't remember the range that the other fellow made a post about from Eric. It must have been a while back, plus what one hears at one way, another may or may not hear at all. Eric uses a set of headphones just plugged in, but laying on the bench. Thats certainly good for a few inch's less than having to listen when there on your head.
JM's was about right, there's not much staying up with the Foster units overall.
Wantmoregold
New member
Mr.Bill,
The posting of Eric's I am referring too is from this forum under the heading "GOLDSCAN 5 and COILTEK COILS" Dated 18 August 2005 and if it works I have included the link below:
http://www.findmall.com/read.php?34,199432,199432#msg-199432
George,
Look forward to you posting your Test results with your upgrade GS5. Hopefully you can also include an Air-Test with a US Nickel Coin as a bench mark for us all to cross-check against the Minelab PI's. If you may, could you please include the Maximum Air-Depth you can reach registering with a Hi/Lo(Wee/Woo)signal on the nickel. The reason I ask,is you can gain an extra 1 inch or more with a "single type" signal sound "Wee" instead of the "double type" signal sound of Wee/Woo, so by using the Hi/Lo type signal this will allow for a more consistent result for others to reference their own tests too.
It was for this reason that I posted the Hi/Lo(Wee/Woo)Air-Depth at max of 14" on the nickel with the 8" mono the GP3000. BTW this depth was in settings: DD/Sens/Deep.
Cheers,
Brian
P.S. I would agree with Eric in my tests that, if the GB is switched off you can gain an extra 1" Air Depth but not with a small coil.
The posting of Eric's I am referring too is from this forum under the heading "GOLDSCAN 5 and COILTEK COILS" Dated 18 August 2005 and if it works I have included the link below:
http://www.findmall.com/read.php?34,199432,199432#msg-199432
George,
Look forward to you posting your Test results with your upgrade GS5. Hopefully you can also include an Air-Test with a US Nickel Coin as a bench mark for us all to cross-check against the Minelab PI's. If you may, could you please include the Maximum Air-Depth you can reach registering with a Hi/Lo(Wee/Woo)signal on the nickel. The reason I ask,is you can gain an extra 1 inch or more with a "single type" signal sound "Wee" instead of the "double type" signal sound of Wee/Woo, so by using the Hi/Lo type signal this will allow for a more consistent result for others to reference their own tests too.
It was for this reason that I posted the Hi/Lo(Wee/Woo)Air-Depth at max of 14" on the nickel with the 8" mono the GP3000. BTW this depth was in settings: DD/Sens/Deep.
Cheers,
Brian
P.S. I would agree with Eric in my tests that, if the GB is switched off you can gain an extra 1" Air Depth but not with a small coil.
Things have changed a lot since that date. That unit he mentions was a unit right at the end prototype stage.
The gain has been extended a lot more since that unit, now that we discovered that the circuit will allow it's use in tough ground.
16"/17" would be more the norm now, using the supplied 11" mono coil. They would be a small increase using the 11" Minelab Commander coil. I haven't tested it using a nickel with the small coil. I will when I get the chance.
The gain has been extended a lot more since that unit, now that we discovered that the circuit will allow it's use in tough ground.
16"/17" would be more the norm now, using the supplied 11" mono coil. They would be a small increase using the 11" Minelab Commander coil. I haven't tested it using a nickel with the small coil. I will when I get the chance.
caliehunter
New member
Air test are relatively useless in the real world,has anyone buried a nickle to see what the machine can really reach for depth. HH Caliehunter
I'm sorry, but air test are not relatively useless in the real world. One needs to have some kind of standard to see if any repairs, adjustments done on a unit made any difference. There is no way that I know of to duplicate any in ground target response the exactly same each time.
With PI detectors it would not be unusual to have an increase with in the ground targets.
This is not cast in stone, and a lot depends on the soil. On a wet salt sand beach a PI's signal tends to be enhanced a tad.
Bill
With PI detectors it would not be unusual to have an increase with in the ground targets.
This is not cast in stone, and a lot depends on the soil. On a wet salt sand beach a PI's signal tends to be enhanced a tad.
Bill
caliehunter
New member
While it may be true that to duplicate a buried target is not possible due to soil variations I have tested units against each other in the air and found that many times the unit that tested better in the air was not better on targets in the ground. And since people buy detectors to look for targets in the ground , test should be done that way for the REAL WORLD of detecting.If you buried a nickle 16'' deep and left it there you could still use it to check adjustments made to the unit. Many times units that perform well in the air don't in the ground therefore why would you want to adjust a unit to AIR CONDITIONS. HH Caliehunter
Prospector Al
New member
It takes two to tango...
Both in-air and buried-target tests are needed to properly evaluate a detector. The basic sensitivity of a detector with a given search coil can be assessed by determining the distance at which a nickel, e.g., is first detected. If the sensitivity is found to be too low--the detection range less that ten inches--there's no need to perform any other tests...put it back on the rack or sell it on E-Bay, if it's yours...
If a nickel is detected at 15-16 inches, the performance in soil should be evaluated. A standardized test can be performed by using pure magnetite (black sand). A wooden box filled with black sand is placed over the target and the change in detection depth is recorded.
As a general rule, the sensitivity of the detector increases for PI machines and decreases for detectors with sinusoidal coil drive.
Some detectors with an improperly designed input circuits can not tolerate much black sand and emit a high-pitched noise which is intended to signify "coil overload". This euphemism tries to convey the impression that a piece of wire in the coil just can't handle any more signal.
The fact of the matter is that the detector ceases to function, because it has a limited dynamic range. If you have such a detector,
sell it on E-Bay...
With sinusoidal coil drive, the magnetic domains in the magnetite try to orient themselves in the direction of the imposed magnetic field.
This phenomenon consumes energy and weakens the field in proportion to the operating frequency of the detector. That's why low frequency detectors were developed. Unfortunately, as the frequency is lowered, so is the voltage induced in the target and a reasonable trade-off has to be made.
In a PI detector, the magnetic pulse generated by the transmitter coil is actually concentrated by magnetite in the ground, much in the same way as a ferrite core in a coil enhances the field strength.
(There are contraptions for sale at most prospecting equipment stores that make it possible to extract magnetite form any kind of soil...)
There are second-order effects, caused by hot-rock-type material which absorbs energy also from a pulsed field, but a basic comparison
between detectors can be made with pure magnetite.
I apologize in advance for these frank opinions--no offense intended...
Prospector Al
Both in-air and buried-target tests are needed to properly evaluate a detector. The basic sensitivity of a detector with a given search coil can be assessed by determining the distance at which a nickel, e.g., is first detected. If the sensitivity is found to be too low--the detection range less that ten inches--there's no need to perform any other tests...put it back on the rack or sell it on E-Bay, if it's yours...
If a nickel is detected at 15-16 inches, the performance in soil should be evaluated. A standardized test can be performed by using pure magnetite (black sand). A wooden box filled with black sand is placed over the target and the change in detection depth is recorded.
As a general rule, the sensitivity of the detector increases for PI machines and decreases for detectors with sinusoidal coil drive.
Some detectors with an improperly designed input circuits can not tolerate much black sand and emit a high-pitched noise which is intended to signify "coil overload". This euphemism tries to convey the impression that a piece of wire in the coil just can't handle any more signal.
The fact of the matter is that the detector ceases to function, because it has a limited dynamic range. If you have such a detector,
sell it on E-Bay...
With sinusoidal coil drive, the magnetic domains in the magnetite try to orient themselves in the direction of the imposed magnetic field.
This phenomenon consumes energy and weakens the field in proportion to the operating frequency of the detector. That's why low frequency detectors were developed. Unfortunately, as the frequency is lowered, so is the voltage induced in the target and a reasonable trade-off has to be made.
In a PI detector, the magnetic pulse generated by the transmitter coil is actually concentrated by magnetite in the ground, much in the same way as a ferrite core in a coil enhances the field strength.
(There are contraptions for sale at most prospecting equipment stores that make it possible to extract magnetite form any kind of soil...)
There are second-order effects, caused by hot-rock-type material which absorbs energy also from a pulsed field, but a basic comparison
between detectors can be made with pure magnetite.
I apologize in advance for these frank opinions--no offense intended...
Prospector Al
, or were you using a VLF discriminating unit ??
If so just what PI units were they ?
I have just about every unit at one time or another, and made such test. With the PI units that tested the same in the shop, did just about the same on the ground between each other. Some units may have been a tad bit more responcive to a particular metal over the other, but overall they came out the same. Case in question; one would be more responsive to gold jewelry over the other, but that one was more responsive to coins. I'm making refference to standard commericial PI detectors.
I was waiting for others to post their results, but I can understand their reluctance to do so.
With my Deepstar using the supplied 11" loop, 15" is not a unreasonable depth on a US nickel at the beach. I have found them many times at that depth. This would also hold true for the Aquastar, and Goldscan 5 id'ing unit.
A little disclaimer; the just released US nickel is not like the past ones, it acts more like iron than a nickel coin, just junk.
If so just what PI units were they ?
I have just about every unit at one time or another, and made such test. With the PI units that tested the same in the shop, did just about the same on the ground between each other. Some units may have been a tad bit more responcive to a particular metal over the other, but overall they came out the same. Case in question; one would be more responsive to gold jewelry over the other, but that one was more responsive to coins. I'm making refference to standard commericial PI detectors.
I was waiting for others to post their results, but I can understand their reluctance to do so.
With my Deepstar using the supplied 11" loop, 15" is not a unreasonable depth on a US nickel at the beach. I have found them many times at that depth. This would also hold true for the Aquastar, and Goldscan 5 id'ing unit.
A little disclaimer; the just released US nickel is not like the past ones, it acts more like iron than a nickel coin, just junk.