NF Evolution Coils Reviews
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You will be finding buckets load of gold now Tathradj 
erfect:
Goody
erfect: Goody
I too have a 17 x13 but not a spoke.
The Tester has done a good job on the write up.
I would like too see one on one of these coils myself as I
only have 1 dd coil myself.
I will be looking very hard at either a 15 or 19 dd.
The Tester has done a good job on the write up.
I would like too see one on one of these coils myself as I
only have 1 dd coil myself.
I will be looking very hard at either a 15 or 19 dd.
Lots of interest on the new X-Search DD coils!
Here's info straight from the horses mouth.
I have started a pre-order list on these.
Here's info straight from the horses mouth.
I have started a pre-order list on these.
Wow, 1650g; need a Sky Hook the balance it on. :Y:
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limpalot said:
Yes, if you're not stuffed pushing it around all day, you certainly will be after digging a target to it's maximum depth :lol:
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I'm looking forward to seeing the specs for the 15" when available.
Hello Nenad
Can you explain in laymans technical terms how these new DD X-Search coils cut through mineralised ground better than say the Evo mono coils?
My understanding is that mono coils, in general over recent years, have become more widely used over DDs because of the advanced signal processing of todays GPX detectors and having a full diameter transmit and receive pattern as opposed to a DD which has half the diameter of the same size mono coil, thus having less depth than the mono.
So Im curious to get a sense of how well the new X-Search DDs will perform in mineralised ground, cutting through the mineralization, and provide more depth even though they have half the transmit pattern of a mono coil.
There seems to be an obvious trade off of ability to cut through mineralization and transmit/receive diameter and Id like to understand the technical theory so I can make an educated buying decision. Im very eager to buy an X-Search coil but dont want to fork out big bucks and be disappointed.
There is a real lack of technical info provided by coil manufacturers.
Thanks so much. Cheers
Can you explain in laymans technical terms how these new DD X-Search coils cut through mineralised ground better than say the Evo mono coils?
My understanding is that mono coils, in general over recent years, have become more widely used over DDs because of the advanced signal processing of todays GPX detectors and having a full diameter transmit and receive pattern as opposed to a DD which has half the diameter of the same size mono coil, thus having less depth than the mono.
So Im curious to get a sense of how well the new X-Search DDs will perform in mineralised ground, cutting through the mineralization, and provide more depth even though they have half the transmit pattern of a mono coil.
There seems to be an obvious trade off of ability to cut through mineralization and transmit/receive diameter and Id like to understand the technical theory so I can make an educated buying decision. Im very eager to buy an X-Search coil but dont want to fork out big bucks and be disappointed.
There is a real lack of technical info provided by coil manufacturers.
Thanks so much. Cheers
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I don't think there's any technical mumbo jumbo involved here.
DD coils by design operate smoother in mineralised ground (sees less ground than a mono) & can also be run in the normal timing over a lot of ground that it wouldn't be possible with a mono.
These 2 points alone can be advantageous over a mono in some mineralised ground.
Also a mono coil with it's cone shaped tx/rx signal can go deeper but does require careful sweep overlap to get the full benefit i.e. a 25" mono will start at 25" transmit but tapers down to a much smaller point at depth. Full ground coverage at depth is difficult.
A 25" DD will transmit at approx. 12" x 25" to it's full depth giving good ground coverage with less careful coil sweep & use of normal over smooth class timings can bring it back to a competitive depth to mono coils (although usually with a larger DD coil over mono).
The main points/claims I see coming from the new DD coils is better sensitivity to small, shallow gold & improved ability to operate in normal timing to add to the other advantages of current DD coils not so much better cutting through mineralised ground?
DD coils by design operate smoother in mineralised ground (sees less ground than a mono) & can also be run in the normal timing over a lot of ground that it wouldn't be possible with a mono.
These 2 points alone can be advantageous over a mono in some mineralised ground.
Also a mono coil with it's cone shaped tx/rx signal can go deeper but does require careful sweep overlap to get the full benefit i.e. a 25" mono will start at 25" transmit but tapers down to a much smaller point at depth. Full ground coverage at depth is difficult.
A 25" DD will transmit at approx. 12" x 25" to it's full depth giving good ground coverage with less careful coil sweep & use of normal over smooth class timings can bring it back to a competitive depth to mono coils (although usually with a larger DD coil over mono).
The main points/claims I see coming from the new DD coils is better sensitivity to small, shallow gold & improved ability to operate in normal timing to add to the other advantages of current DD coils not so much better cutting through mineralised ground?
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Id be happy with that. What a find
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Just to illustrate (& correct :8 ) what I wrote above.
The below picture shows a good representation of DD v mono coil detection fields.
I had written "A 25" DD will transmit at approx. 12" x 25" to it's full depth". As seen from the illustration this would be less than ~30% of the coil diameter depending on how much overlap the manufacturer uses so it would be more like <7" x 25".
Image from: https://www.bigboyshobbies.net/double-d-coil-vs-concentric-coils/
The below picture shows a good representation of DD v mono coil detection fields.
I had written "A 25" DD will transmit at approx. 12" x 25" to it's full depth". As seen from the illustration this would be less than ~30% of the coil diameter depending on how much overlap the manufacturer uses so it would be more like <7" x 25".
Image from: https://www.bigboyshobbies.net/double-d-coil-vs-concentric-coils/
mbasko
I understand the diagram but it may not be 100% correct, because from what I understand and you alluded to a DD does not punch as deep because the transmit coil is half the size of the same diameter mono. The diagram I believe should show the DD depth being less than the same size mono. I am I correct with this thinking?
Cheers
I understand the diagram but it may not be 100% correct, because from what I understand and you alluded to a DD does not punch as deep because the transmit coil is half the size of the same diameter mono. The diagram I believe should show the DD depth being less than the same size mono. I am I correct with this thinking?
Cheers
With the dd running in normal and not special or enhanced on a 4500 or 5000 that makes a big difference ,most spots trying to run a mono in normal is near imposable regards john :Y:
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The diagram would be more about illustrating the detection fields not being depth comparison correct.
There are many factors that will affect depth like salt/mineralisation, conductivity, EMI, etc.
In theory:
Using the same sized coils in moderate/less mineralised ground the mono should punch deeper & be more sensitive.
In more mineralised ground where using a DD allows use of normal timing then the same size DD could potentially go as deep or deeper than the mono but with a loss of sensitivity.
In ground or conditions i.e. salt, EMI where it's very difficult to run a mono at all then the advantages of a DD coil can come into it's own.
Extra sensitivity & an improved ability to operate using normal timing are the real improvements with these new DD's IMO if they live up to that.
Detech pretty much kick started it with their 15" DD Ultimate spiral coil so it will be interesting to see how people compare them.
There are many factors that will affect depth like salt/mineralisation, conductivity, EMI, etc.
In theory:
Using the same sized coils in moderate/less mineralised ground the mono should punch deeper & be more sensitive.
In more mineralised ground where using a DD allows use of normal timing then the same size DD could potentially go as deep or deeper than the mono but with a loss of sensitivity.
In ground or conditions i.e. salt, EMI where it's very difficult to run a mono at all then the advantages of a DD coil can come into it's own.
Extra sensitivity & an improved ability to operate using normal timing are the real improvements with these new DD's IMO if they live up to that.
Detech pretty much kick started it with their 15" DD Ultimate spiral coil so it will be interesting to see how people compare them.
I appreciate everyones feedback.
I actually have a Detech 15 flat wind DD Ultimate and cant run it in normal in the Vic GT. The mineralization is still too much for it. And its a heavy beast for no improvement over a much lighter 15 Evo flat wind mono which I also have and love. So Ive probably answered my own question. My experience and deduction is that 15 DD, lets say with effective 8x15 diameter transmit, actually cuts through the mineralization better than the 15 diameter transmit mono, and actually does detect just as deep as a 15 Evo mono, with both running in Enhanced and all other settings the same; but the DD is a lot heavier. So where is the benefit in highly mineralised ground for a flat wound DD? Perhaps there isnt one.
Id appreciate any experience or comment to the contrary. Cheers
I actually have a Detech 15 flat wind DD Ultimate and cant run it in normal in the Vic GT. The mineralization is still too much for it. And its a heavy beast for no improvement over a much lighter 15 Evo flat wind mono which I also have and love. So Ive probably answered my own question. My experience and deduction is that 15 DD, lets say with effective 8x15 diameter transmit, actually cuts through the mineralization better than the 15 diameter transmit mono, and actually does detect just as deep as a 15 Evo mono, with both running in Enhanced and all other settings the same; but the DD is a lot heavier. So where is the benefit in highly mineralised ground for a flat wound DD? Perhaps there isnt one.
Id appreciate any experience or comment to the contrary. Cheers
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Hi Andy, when you have the dd on and flick over to Normal timings are you keeping the setting the same or dropping the RX?
Normal RX 6 would be more powerful than Enhanced RX 12 and that is where you should be able to run the dd coil in Normal and gain the advantage over the mono in Enhanced.
Just my experience on a test patch on hot ground.
Normal RX 6 would be more powerful than Enhanced RX 12 and that is where you should be able to run the dd coil in Normal and gain the advantage over the mono in Enhanced.
Just my experience on a test patch on hot ground.
A friend had a new 25 dd out last week on a new 4500 running it in normal and he was amazed how quiet it run ,he rang me to tell me :Y:
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And that I believe is the point with the new NF DD's - improved ability to operate in normal in very mineralised ground.old hand said:
Be interested to hear his thoughts on the sensitivity also.
Dignit - I had heard that the Detech 15" DD Ultimate spiral coil was an improvement on sensitivity but could still be noisy in high mineralisation. Having not used one I was reluctant to say it so thanks for the feedback on them altbough I'm curious to see how you ran it as per Petes post above.
ProspectorPete said:
PP
Ive tried all sorts of settings, lower Rx etc with the DD in normal, as Ive done with the Evo but didnt see any better performance than doing the same things with the Evo so stick to the Evo as it is so much lighter. I only put the DD on in trashy areas and use discrimination.
However, I may give what youve tested another go. Some buried test nuggets is what I should do.
Cheers
