nero_design
New member
I started to write this Thread as part of an answer to someone else's question. However, I ended up writing more information than I expected to... and rather than paste this into the reply, I thought it would be better off to place these details in a separate thread.
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As someone who wanted to start out detecting beaches and occasionally go out the the Gold Fields, I seem to find myself doing things the other way around.
Prospecting has become my hobby now and I had to look at buying an additional coil or two on order to have any success.
There's three main coils to be considered in the High Frequency range for the X-Terra 70:
The 10.5" DD HF Coil (Better for beach and field but possibly not so much for Gold Prospecting for smaller nuggets)
The 5x10" DD HF Coil (Elliptical, Shaped to use in Difficult Terrain, Replaceable Skid Plate)
The 6" DD HF Coil (Super Sensitive/Waterproof/ NO replaceable Skid Plate)
It's my understanding that the DD High Frequency Coils are particularly good in the sort of mineralized soils that gold typically is found in.
I have the 5x10" DD HF and the 6" DD HF coils. Both are completely different to one another, even though they are both High Frequency DD coils. I imagine the 10.5 DD is also quite different although it was not recommended to me for Prospecting so I have not yet purchased one.
[size=large]5x10" Elliptical Double D High Frequency (18.75khz) Coil:[/size]
The 5x10" is probably best for exploring areas where gold might be found. Larger signal blade means more area can be covered, especially the sort of iron-filled soils near where I detect. But this blade-like Emission Field is weaker, wider and a little shallower that I would prefer. It has a replaceable skuff cover but it's not water-proofed (for immersion) where the cable meets the coil itself. It has quite a wide field of detection near the coil (see the green Halo in the illustration). The blade area of the coil emission is a little broad compared to the 6" coil. The coil is sensitive to metal but NOT to really small nuggets (eg: smaller than 1/5 of a gram, if it's a few inches under the surface, probably won't register).
[size=large]6" Elliptical Double D High Frequency (18.75khz) Coil:[/size]
The 6" coil is probably best suited to careful scanning of areas where finer specimens might be found. A much smaller coil, this is also MORE sensitive but the user should work slower on the same ground due to the smaller detection field. If you were visiting a known site for gold, this is a pretty handy coil. It is waterproof and can be immersed in streams to search from clumps of smaller gold, small specimens in quartz or even very small nuggets. I tested this coil on a 0.02g 'micro-nugget' and found it responded nicely if the target this small is on the surface. That's a pretty small fleck of gold too! The 5x10" Elliptical Coil could NOT detect a sample this small under any circumstance. The Emission Field is almost like a knife blade on the 6" DD. I believe the Emission Field on the 6" to be sharper in shape and far more sensitive to gold that the Elliptical although the Elliptical is capable of detecting gold that is not near the actual coil or the blade.
I'm fond of both these coils but I'm baffled as to which coil to use myself sometimes.
I like the Elliptical. It even looks good on the detector. But if it misses VERY small gold, then I wonder sometimes if it's strong enough for me to rely on it. It costs me time and money to get to the right place and I have to take into account many other things including weather. I don't want to waste time with the wrong coil. Should I use the Elliptical and then change coils if I find something? I honestly don't know ...but this is what I have done in the past. Like owning a camera with two different lenses: if you take an expensive vacation and one lens is damaged or breaks... you can still complete your trip and take pictures with the remaining lens, regardless of the zoom. Same goes for coils. In some instances, serious prospectors take two detectors with them in case of mishap. So carrying an additional coil with me may have its benefits.
In under a week, I am traveling to a location which was once VERY rich in nuggets in the mid-1800s. I just found the details last night (!) which few people know about since it wasn't considered to be as high profile as other gold fields near here. I stayed up last night till 6am marking the map that my friend will use to navigate us there. But since the area has been dug up and 'thoroughly thrashed' (as they say) by other miners and later... detectorists, I'm going to consider detecting the area with the 6" coil. This is because I believe that any gold remaining would need to be small enough to have been missed by people who got there before me. And any larger nuggets will likewise be visible to this coil as long as the Emission Field passes over them. I believe the 6" coil penetrates deeper than the Elliptical and that may be important. I might be wrong too. But Nuggets on the surface should trigger an immediate response with either coil.
Below is the Business Card-sized manual that I used to keep in my pocket to remind me which settings to start off in.
I've pretty much memorized these details but am posting them here in case others want to print them out for use. Bit of a "Startup For Dummies" which I made after i realized I was neglecting the correct process myself at the beginning. I think I wasted my first three days with the X-Terra 70 by hitting the buttons in the wrong sequence. There's a few experienced detectorists here who wouldn't have use for it but I thought it might come in handy for newbies who don't want to carry their manual around with them on their first few trips.
Cheers,
Marco
[attachment 82999 X_TERRA70_CARD.jpg]
[size=small]Fold Down the Middle. Laminate if desired.[/size]
_____________________________________________________________________
As someone who wanted to start out detecting beaches and occasionally go out the the Gold Fields, I seem to find myself doing things the other way around.
Prospecting has become my hobby now and I had to look at buying an additional coil or two on order to have any success.
There's three main coils to be considered in the High Frequency range for the X-Terra 70:
The 10.5" DD HF Coil (Better for beach and field but possibly not so much for Gold Prospecting for smaller nuggets)
The 5x10" DD HF Coil (Elliptical, Shaped to use in Difficult Terrain, Replaceable Skid Plate)
The 6" DD HF Coil (Super Sensitive/Waterproof/ NO replaceable Skid Plate)
It's my understanding that the DD High Frequency Coils are particularly good in the sort of mineralized soils that gold typically is found in.
I have the 5x10" DD HF and the 6" DD HF coils. Both are completely different to one another, even though they are both High Frequency DD coils. I imagine the 10.5 DD is also quite different although it was not recommended to me for Prospecting so I have not yet purchased one.
[size=large]5x10" Elliptical Double D High Frequency (18.75khz) Coil:[/size]
The 5x10" is probably best for exploring areas where gold might be found. Larger signal blade means more area can be covered, especially the sort of iron-filled soils near where I detect. But this blade-like Emission Field is weaker, wider and a little shallower that I would prefer. It has a replaceable skuff cover but it's not water-proofed (for immersion) where the cable meets the coil itself. It has quite a wide field of detection near the coil (see the green Halo in the illustration). The blade area of the coil emission is a little broad compared to the 6" coil. The coil is sensitive to metal but NOT to really small nuggets (eg: smaller than 1/5 of a gram, if it's a few inches under the surface, probably won't register).
[size=large]6" Elliptical Double D High Frequency (18.75khz) Coil:[/size]
The 6" coil is probably best suited to careful scanning of areas where finer specimens might be found. A much smaller coil, this is also MORE sensitive but the user should work slower on the same ground due to the smaller detection field. If you were visiting a known site for gold, this is a pretty handy coil. It is waterproof and can be immersed in streams to search from clumps of smaller gold, small specimens in quartz or even very small nuggets. I tested this coil on a 0.02g 'micro-nugget' and found it responded nicely if the target this small is on the surface. That's a pretty small fleck of gold too! The 5x10" Elliptical Coil could NOT detect a sample this small under any circumstance. The Emission Field is almost like a knife blade on the 6" DD. I believe the Emission Field on the 6" to be sharper in shape and far more sensitive to gold that the Elliptical although the Elliptical is capable of detecting gold that is not near the actual coil or the blade.
I'm fond of both these coils but I'm baffled as to which coil to use myself sometimes.
I like the Elliptical. It even looks good on the detector. But if it misses VERY small gold, then I wonder sometimes if it's strong enough for me to rely on it. It costs me time and money to get to the right place and I have to take into account many other things including weather. I don't want to waste time with the wrong coil. Should I use the Elliptical and then change coils if I find something? I honestly don't know ...but this is what I have done in the past. Like owning a camera with two different lenses: if you take an expensive vacation and one lens is damaged or breaks... you can still complete your trip and take pictures with the remaining lens, regardless of the zoom. Same goes for coils. In some instances, serious prospectors take two detectors with them in case of mishap. So carrying an additional coil with me may have its benefits.
In under a week, I am traveling to a location which was once VERY rich in nuggets in the mid-1800s. I just found the details last night (!) which few people know about since it wasn't considered to be as high profile as other gold fields near here. I stayed up last night till 6am marking the map that my friend will use to navigate us there. But since the area has been dug up and 'thoroughly thrashed' (as they say) by other miners and later... detectorists, I'm going to consider detecting the area with the 6" coil. This is because I believe that any gold remaining would need to be small enough to have been missed by people who got there before me. And any larger nuggets will likewise be visible to this coil as long as the Emission Field passes over them. I believe the 6" coil penetrates deeper than the Elliptical and that may be important. I might be wrong too. But Nuggets on the surface should trigger an immediate response with either coil.
Below is the Business Card-sized manual that I used to keep in my pocket to remind me which settings to start off in.
I've pretty much memorized these details but am posting them here in case others want to print them out for use. Bit of a "Startup For Dummies" which I made after i realized I was neglecting the correct process myself at the beginning. I think I wasted my first three days with the X-Terra 70 by hitting the buttons in the wrong sequence. There's a few experienced detectorists here who wouldn't have use for it but I thought it might come in handy for newbies who don't want to carry their manual around with them on their first few trips.
Cheers,
Marco
[attachment 82999 X_TERRA70_CARD.jpg]
[size=small]Fold Down the Middle. Laminate if desired.[/size]
I just got my X70 late last Fall so am very anxious to get out this Spring and do some serious detectiong. I hunt about 90% of my time with some real tough competition so the more I can learn the better my edge might be.
I live in an area that has very low mineralizattion so CC coils work rather well here. I have the stock 9" 7.75Khz, 6" 7.75Khz cc, 9" 3khz, and just recently traded my 6" 18.75Khz for a 5X10 Elip 18.75Khz. Reason being the two 6" coils performed very similar in my area, but still wanted a high frq coil. The elip coil I am hoping may give me better ground coverage in the many corn filed we hunt and still have that 18.75Khz for those lost gold coins. Your read gives me confidence I did the right thing for my area of the country as I don't have the opportunity to find any raw gold. 
