Coil questions and information

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BigWave said:
There's a twist though, pick your coil for the likely ground depth. In shallow ground, a 14*9" will find the small nuggets plus the shot (if that's all there is), whereas in slightly deeper ground (say to 12") the 11" mono will miss much of he shot (at not more than 2"), but will find the loot. In deeper ground, we need to use a 15" plus. What a lot of detectorists fail to realise is ground depth. Match your coil to ground depth.
BW, what do you do to ascertain your ground depth in the area that you're about to detect, do you get the pick out first and dig around to check for ?.....just a learners' query.
 
Hi OzzieAu. I'm no expert here, but there's quite a few simple pointers, including: inspecting previous (and newer) diggings, surface iron (rounded blobs of laterite), rust coloured ground, surface gravels/rock/reef (even clays), slope of the ground, salt and pepper around tree trunks, changes in vegetation can indicate changing ground depth (or mineralisation or both), the condition of whipsticks (dead and bent over because they couldn't penetrate), the depth of old buckshot etc. I'm sure there's many more that I've missed and that others could add. Then there's your pick.
 
A great coil is the one that matches up perfectly to the detector you are using, that suits the ground conditions you are working, and is optimised for the gold that is still sitting in the ground. So, I know a 5000 and the 12" Evo is a great combo a lot of the time, but isn't going to be great everywhere. Very deep ground you want something bigger, and if there's HV power lines or electric fences about, you'll need a DD coil or you simply leave that area.

I guess when it comes to coils for the GPX's, you can put them in 3 groups:

1. Early pre-gpx coils.
These are traditional wound coils, some using Litz wire, others not, that were optimised for the detectors that were out at the time. Examples are Minelab Super Gold Search coils, Coiltek terracotta monos & DDs, and some early Nugget Finder fiberglass coils. A lot of these would be hit and miss as to how compatible they are with GPX detectors, especially the 5000 which is a little more fussy on coil specs with its 8 timings.

2. Post-gpx traditional wound coils.
These are all the coils that were wound to be compatible with the GPX series, particularly once the 5000 came out. Minelab Commander, Minelab GP series DD's, Nugget Finder Advantage series, Coiltek Goldstalker (in particular the Blitz as it used Litz wire), and all Detech coils. These coils were basically wound to a tight specification to ensure they work well with the GPX5000, so you'll find very little performance difference between similar sizes - apart from mechanical build and quality differences.

3. Flat/spiral wound coils.
These are the new generation of coils, which Dave NT has covered pretty thoroughly. The performance differences between the Elites, Evos, and Detech Ultra Sensing are hair splitting, that I think it's almost not worth worrying about. The main differences are weight, build quality and of course price. Evo's being most expensive, then Elites then the Detech's are just under. Size for size, Evo's are the lightest, especially the spoked versions, then the Elites and Detechs are neck n neck.

Hope that helps clear up a few things Daz.
 
Asking the question has given me the info i needed to except that probably the coils I have will do the job. I hope asking the question will make this post a reference point for anyone else too.
 
What about bumping up to a Nugget Finder 17x13 Evo for more depth on larger gold? I know from my own testing the new tech coils go up to 2-3 inches deeper than stock coils. I just couldn't give that depth advantage up myself. I run a 14x9 Evolution and a 14" round Elite mono. Seems to cover all the bases for me, I do prefer the elliptical since it pinpoints much faster. If I didn't already have the Elite 14" round I would buy the NF Evo 17x13.
 
Gday all.

Reading a thread in the for sale and swap section today. I noticed there were members wishing to swap similar sized NF coils, some were round and others elliptical.
I am aware of the advantages from both shapes and what they can provide.
For the GPX series If you could have any 5 coils (size & shape) for general everyday detecting, what would they be?
This may help others in the future decide their arsenal.
 
19" evo, 12"evo, 18"nfa, 16"nfa, all mono, all spoked. all round. 12x7 nfa mono, elliptical, 8"ml commander mono, i9"z. 12" ml dd.
I feel that round gives a bit more depth than elliptical, and spoked are easier to swing over long periods of detecting,lighter. They're all excellent coils, which have different advantages for different conditions. wiley coyote.
 
Hmmm, this is a tuff one

1. 19" Evo - gotta have a big round coil, and I like that the Evo doesn't give up too much sensitivity

2. 17x13" Evo - would have to be the best patch hunter at the moment, very sensitive, good coverage and nice and light

3. 15" DD Detech Ultimate - utility coil, gotta have a DD coil in the arsenal

4. 11" Detech Ultra (can't fit both the 12" & 14x9" Evos into the list, so the 11" Detech is a nice go between)

5. 12x7" Advantage - need to have a non spiral coil in the kit, something that will handle the hot clays and surfaced areas, and allow me to work thick scrub

Funny though, if the list said I can only take 2 coils with me, it would be 15" Evo and 14x9" Evo :cool:
 
Actually that was quite fun, got me thinking what about a top 5 for other detectors.
Seems quite a few 3500's are still kicking around, so here are my picks.

1. Detech 8" DD - solid, quiet and sensitive

2. 12x7" NFA - in quieter ground, these are just awesome on the 3500 in Sensitive.

3. 15x12" Commander Mono - as above, but will handle mild/warm ground okay, and very good depth

4. Detech 15" DD Ultimate - a perfect match to the 3500, can use it in Normal DD for depth, or Sens/Mono for the smaller stuff

5. This needs to be a big deep coil. Depends where you are, but would be a toss up between the 18" GP extreme coil, or the 18" Super Goldsearch (fiberglass/kevlar).
 

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