A
Anonymous
Guest
i read somewhere that most coiltec coils will work on the goldscan. did i read right? if so, which one's? thanks
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A
Anonymous
Guest
While you are answering that Question I add this question...the Coiltek Pro line of coils require additional power by 20%; Would there be any risk to the Goldscan-5 if an 11x17 DD Pro was used on the Gold scan? How about a 12x24 DD PRO?
Thanks
fred
Thanks
fred
Eric Foster
New member
Hi David and Fred,
The coils I have tried are the Minelab 11in mono and DD, and the Coiltek 14in DD. These worked fine, and knowing those coil's parameters, I predict that other coils designed for the SD/ GP will work OK in most cases. The Minelab detectors are quite critical of coil parameters, and deviating too far, they just won't work. The Goldscan, however is very tolerant of coil variations in inductance and resistance ( within certain limits of course), due to its constant current feature in the transmitter. I assume that the Coiltek Pro coils are even lower in resistance than the standard ones at about 0.4 ohms. This does not matter as any coil from 0.1 ohms to 4 ohms will run at the same current on the Goldscan.
Eric.
The coils I have tried are the Minelab 11in mono and DD, and the Coiltek 14in DD. These worked fine, and knowing those coil's parameters, I predict that other coils designed for the SD/ GP will work OK in most cases. The Minelab detectors are quite critical of coil parameters, and deviating too far, they just won't work. The Goldscan, however is very tolerant of coil variations in inductance and resistance ( within certain limits of course), due to its constant current feature in the transmitter. I assume that the Coiltek Pro coils are even lower in resistance than the standard ones at about 0.4 ohms. This does not matter as any coil from 0.1 ohms to 4 ohms will run at the same current on the Goldscan.
Eric.
A
Anonymous
Guest
thanks for the fast reply eric. im wondering if the mothership & the 12-24 ufo would work?
Hi David,
My guess is the large coil would work on the GS 5. However, it might not work at the minimum delay setting of 10 usec Eric has designed into the GS 5. The 10 usec minimum delay is quite a feat for a high powered PI. With this short of a delay, there is a clear increase in the sensitivity to the really small gold as well as all larger gold objects. However, such a short delay now makes coil building very critical. A coil as large as you mentioned may not work at the extremely short delay. It will most likely require a longer delay before sampling to work correctly. The extra time is needed for the decay curve to properly settle down to "0" Volts. Again, this is common on larger coil. The larger the coil, the greater the problem.
So, most likely any ML compatible coil will work just fine, but it will require the delay control be increased a little on the larger ones. My guess is it will not take too much of an increase, maybe somewhere between 12 usec and 15 usec. This is still fast enough for most small gold as well as all larger gold nuggets. At this setting, it will be closer to some of the other PI sampling times.
I have worked with some of Eric's detectors and they are very forgiving as he mentioned. However, because larger coils take longer for the signal to decay to zero volts, the extremely high gain Eric uses causes some things to occur when other coils are used. What basically happens in technical terms is larger coils just take longer to settle down than do smaller coils. So, any 10 usec sampling on a larger coils will occur too early on the decay curve which will result in one of the amplifiers becoming saturated with too strong of a signal. This will result in the detector appearing to lose most of its sensitivity. Is this a dangerous problem, or will it hurt anything? Nope, but the detector will not work correctly either.
So, what is needed to adjust for this situation is to simply advance the delay a little. Once the sample is taken at the proper time on the coil decay curve, then the amplifier is no longer saturated and suddenly, the detector will appear to work just fine.
So, if you try a large ML PI compatible coil on one of Erics detectors (the GS 5 or the GQ V2 with an adapter) and it appears to have very little sensitivity, just turn the delay control up a little while testing over a target. At some point in the adjustment, the sensitivity of the detector should suddenly increase to normal.
When Eric's coils are used, this situation is not something that is encountered. However, since Eric has designed the GS 5 for maximum versatility and allows for different coils to be used, then some trade offs can occur. This is one of them.
Now, Eric could "detune" the GS 5 and eliminate this situation. NA, bad idea.
Reg
My guess is the large coil would work on the GS 5. However, it might not work at the minimum delay setting of 10 usec Eric has designed into the GS 5. The 10 usec minimum delay is quite a feat for a high powered PI. With this short of a delay, there is a clear increase in the sensitivity to the really small gold as well as all larger gold objects. However, such a short delay now makes coil building very critical. A coil as large as you mentioned may not work at the extremely short delay. It will most likely require a longer delay before sampling to work correctly. The extra time is needed for the decay curve to properly settle down to "0" Volts. Again, this is common on larger coil. The larger the coil, the greater the problem.
So, most likely any ML compatible coil will work just fine, but it will require the delay control be increased a little on the larger ones. My guess is it will not take too much of an increase, maybe somewhere between 12 usec and 15 usec. This is still fast enough for most small gold as well as all larger gold nuggets. At this setting, it will be closer to some of the other PI sampling times.
I have worked with some of Eric's detectors and they are very forgiving as he mentioned. However, because larger coils take longer for the signal to decay to zero volts, the extremely high gain Eric uses causes some things to occur when other coils are used. What basically happens in technical terms is larger coils just take longer to settle down than do smaller coils. So, any 10 usec sampling on a larger coils will occur too early on the decay curve which will result in one of the amplifiers becoming saturated with too strong of a signal. This will result in the detector appearing to lose most of its sensitivity. Is this a dangerous problem, or will it hurt anything? Nope, but the detector will not work correctly either.
So, what is needed to adjust for this situation is to simply advance the delay a little. Once the sample is taken at the proper time on the coil decay curve, then the amplifier is no longer saturated and suddenly, the detector will appear to work just fine.
So, if you try a large ML PI compatible coil on one of Erics detectors (the GS 5 or the GQ V2 with an adapter) and it appears to have very little sensitivity, just turn the delay control up a little while testing over a target. At some point in the adjustment, the sensitivity of the detector should suddenly increase to normal.
When Eric's coils are used, this situation is not something that is encountered. However, since Eric has designed the GS 5 for maximum versatility and allows for different coils to be used, then some trade offs can occur. This is one of them.
Now, Eric could "detune" the GS 5 and eliminate this situation. NA, bad idea.
Reg
A
Anonymous
Guest
n/t
Hi Fred,
I mentioned what might happen with larger coils on the GS 5 in another post in this general thread. About the only negative thing that can happen is one might be required to increase the delay a little to make the coil work properly.
Now, as for your power question, Eric mentioned in some earlier posts that he has a built in current limiter that will limit the current in the coil. So, regardless of the type and brand of coil used, it will only draw 2 amps max.
So, there is no way any special coil will have a negative impact on the detector. Besides, the FET used in the GS 5 can more than handle multiple times the current than can be drawn, so nothing negative can happen there.
Like Eric's other machines, this one is about bullet proof also. They are designed to last a very long time.
Reg
I mentioned what might happen with larger coils on the GS 5 in another post in this general thread. About the only negative thing that can happen is one might be required to increase the delay a little to make the coil work properly.
Now, as for your power question, Eric mentioned in some earlier posts that he has a built in current limiter that will limit the current in the coil. So, regardless of the type and brand of coil used, it will only draw 2 amps max.
So, there is no way any special coil will have a negative impact on the detector. Besides, the FET used in the GS 5 can more than handle multiple times the current than can be drawn, so nothing negative can happen there.
Like Eric's other machines, this one is about bullet proof also. They are designed to last a very long time.
Reg
Eric Foster
New member
Hi Reg,
Many thanks for the "in depth" explanation. The full range of the delay control on the GS5 is 10uS - 25uS. Other PI's I make, have a wider range e.g. 10uS - 40uS on the Goldquest, but the reasons for reducing it are these.
1) The ground cancelling circuit imposes limits on the maximum delay that can be used.
2) The reduced range makes it easier to fine tune the detector to other coils.
3) There is no reason to have a wider range for nugget and ring hunting. The wider range on other machines is so that one can do "reverse discrimination", if needed. On the GS5 it is easier to identify iron by means of the two tone audio.
Eric.
Many thanks for the "in depth" explanation. The full range of the delay control on the GS5 is 10uS - 25uS. Other PI's I make, have a wider range e.g. 10uS - 40uS on the Goldquest, but the reasons for reducing it are these.
1) The ground cancelling circuit imposes limits on the maximum delay that can be used.
2) The reduced range makes it easier to fine tune the detector to other coils.
3) There is no reason to have a wider range for nugget and ring hunting. The wider range on other machines is so that one can do "reverse discrimination", if needed. On the GS5 it is easier to identify iron by means of the two tone audio.
Eric.
When I was in the Arizona desert in April testing the Goldscan 5, I had a chance to test it with the large coils. My host Bill Southern, brought along a few Nugget Shooter coils, and his GP 3500. This gave me a half a dozen Minelab compatible coils to try on the Goldscan 5.
I had been testing with little tiny bits of gold nuggets. They were small enough that I didn
I had been testing with little tiny bits of gold nuggets. They were small enough that I didn