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Back to Basics.......Coil selection.:biggrin:

BarnacleBill

New member
I've noticed many posts lately concerning coil selection. The responses have been varied as to the "best" or "most used" coil. The variety of opinions is exactly what should be expected based on the purpose of the X-Terra design platform. By it's nature it was was meant to be personalized without being hamstrung by a general purpose single frequency as ALL other mid-range detectors are. I've seen several posts stating that their preference would not be the 7.5khz stock concentric coil. Stop a moment and think about what all the other manufacturers offer in this price range, answer..... a single frequency that you live with.

The stock coil, which many here seem to view as a compromise is very close in frequency to many recent releases by other manufacturers. It may not be a dedicated hobbyist's first choice that concentrate on a particular aspect of this hobby, but it is a good basic coil that will serve one well in a wide variety of tasks. Keep in mind a very small percentage of detectors purchasers are forum hounds or involved in the hobby as many here are. The stock coil provides a good balance of capability.

Now by example I will lay out why I use what coils I do and why. I am primarily a beach/water hunter with most of my time spent on freshwater. My number one target is gold jewelry! Many years ago I was primarily a park/relic hunter, but I caught gold fever! If I was still involved in that type of hunting then the 3kHz & 7.5kHz would be the coils of primary interest for me. But I've evolved(some may say devolved :laugh:) into a wader.

So what is it that the X-Terra offers me a wader? Simple, the higher frequency that is more sensitive to small gold jewelry. And the coils are optimized for that frequency with no compromise, as in non-resonant designs that depend on harmonic response. The second aspect is clean rejection of iron. That is, the ability to set the discrimination to reject iron but still effectively hear small gold.

Are there other detectors operating at a similar high frequency? Yes several, and I did use a Tesoro Tejon for a year because of it's sensitivity to small gold. But in the end the Tejon had an achille's heel, terrible iron rejection. It suffered from such severe iron breakthrough that by the time small rusty nails were effectively rejected, so was all of the small gold. I have very high expectations of discrimination circuits at the iron to foil transition point. If I set a coin detector to reject small iron, I better not hear it, but I do want to hear small bits of foil. I still use a couple of original Fisher detectors which have excellent iron rejection(Excel & Edge) but they can't match the sensitivity of the HF coils with the X-Terra for small gold.

Does any of this mean that I'd not recommend someone else not use the other coils I don't use? Heck no! That's the strength of the platform! It's like ordering food in a Chinese restaurant, one from column A, one from column B, & one from column C.:lol:

Within the above context, think about the X305. What's the price point of the other detectors on the market that offer a dual medium and high frequency like the X-Terras? How would the X305 with the 6 inch DD HF coil fare against those "other" detectors in a trashy park? Garrett, FT, Tesoro, White's, be afraid, be very afraid!

HH
BarnacleBill
 
I agree with what you say BarnacleBill and agree that the stock coil is probably the best compromise coil if you only had one. I have found that I use the 6" DD HF almost exclusively though since the ballpark parking lot I spend most of my time in is so littered with gum foil, bottle & tab tops and god only knows what all the iron is since I don't dig it. I am after coins & jewelry when there and the density of junk is almost too much even for the 6" and if I try to use anything larger I don't find much. I have also used the 6" on the beach and even though I don't cover ground rapidly I have found things as small as a stud earring and tiny bits of copper wire less than 1/2" long so I know if I pass the coil over any jewelry I will find it if its not too deep. The 6" DD HF seems to hit coins just as well as the stock coil. I have other coils and will use them to suit the situation, but so far I keep having the best luck with the 6" DD HF and at age 66 I really like the lite weight and its waterproof and I have done a little wading in salt water when it was smooth enough all I found was junk but it does work in salt water if its smooth enough to keep the coil just off the bottom.

When I bought the X-70 a year ago I knew absolutely nothing about metal detectors and didn't even know there were other coils available or what to do with them. But after reading the forums a lot and planning for a trip to Australia I ordered 3 other coils and through experimentation found that I use the 6" DD HF the most. It would ground balance on the hot Aussie beaches and seemed better in the gold fields (no gold, just bird shot, .177 pellets, 22 slugs etc.) than the 5"X10" when I encountered some hot iron rocks. If I go someplace to hunt relics I will start out with my 10.5" DD MF but it is significantly heavier and slightly unbalances the machine. I am very pleased that we have such a range of coils available with one machine.

If one does know what type of hunting they do, I thing it would be great if they were offered with your coil of choice even though I wouldn't have known enough to make a decision when I bought mine. I am just very glad that the seller recommended the X-70 when I told him I wanted to hunt beaches, parks and occasional gold.
 
Bill, that is a very good post above. Besides the great X-70(705), 505, or 305 with HF coils, did you ever try the other gold prospecting units, either multi-purpose or dedicated, for finding very small gold jewerly on the vast sandy beach stretches, and at the same time rejecting iron very well, like the MXT(with larger SEF coils), GMT, Gold Bug-2(in the discrimination mode with 14" elliptical coil), Fisher Gold Strike, Tesoro Lobo ST(with the H.O.T. 10x12 DD), Tesoro Tiger Shark, or Eureka Gold(with 15" WOT DD), and you may not agree with this one, I dare say the 5 kHz Musky(15" WOT DD)?
 
BarnacleBill your are a smart man skilled in the arts of detecting. Its good to see people that like this hobby and put the time in it to help others. I have used the 18.75klhz 9inch concentric coil on my xterra 305 wich by the way is a great detector much improved over the 30. But i prefer the stock 7.5klhz to use most of the time because i am a park hunter more than a beach hunter , and hunt mostly coins and jewlry. Now they are both good coils and so is the 3klhz as well. But i figured like you that most manufactures use around 7.5klhz for there stock coils with the exception of a few. So far ive found 3 rings with my stock coil and manny interesting coins.The xterras are good machines and the people on this forum are great because they share information and help others on. Good hunting to all:minelab::pulltab:
 
I also agree with what you say BarnacleBill. Yesterday I waded a fresh water beach for the first time with my 705 and liked it. I found some clad coins and one ring and was amazed at its performance in water. Which of the HF coils do you prefer for fresh water beach wading?
 
David part of my post above was to present my perspective of choosing a detector that meets my needs based on a decision matrix. And based on "my" criteria most of the detectors you mentioned are not even in the ballpark. That doesn't mean they are "bad" detectors or incapable. Therefore I'll be a little more detailed about how I arrive at my current choices.

I spend about 80% of my time in freshwater wading, 10% along the freshwater shoreline, & 10% saltwater hunting. But there is a weighting factor of importance here, and that 10% saltwater hunting is where I hunt in the winter when the lakes I visit are frozen over. And that winter hunting is very important to me, it gets me off the couch out walking and keeps my detecting chops up to speed. Therefore I look at detectors that can handle both areas, with of course the caveat thrown in of some hot ground/hot gravels & sand so black that it sucks sunlight in.

Below is an example of a freshwater beach I visit on a lake that was once considered for mining the bottom for iron ore. The black sand is seen in contrast to a Tesoro Stingray II coil, and the rocks in the water are laced with iron, many of them being magnetic. The Stingray II did not like this beach in the least, which along with not so great iron disc is the reason it went down the road.

[attachment 133476 aggrav.jpg]

Below is a staged photo on a saltwater beach in a damp sand area. I say that because where the sand is wet the beach appears jet black. The photo was staged carefully to provide contrast between dark & light. The visual cues being the white coil rod of the CZ-20 against the sand, the light colored pine of the wooden ruler & shovel handle in the foreground, and lastly how close in color the arm cuffs, hand grips & coils are to the sand.

[attachment 133477 york.jpg]

The above are just some of my mineralization issues along with being able to handle saltwater itself when thrown into the decision tree.

Next is discrimination, the saltwater beaches are best detected after a major storm, but the storms also bring in iron scale that's about the size of many coins and fools many detectors even using concentric coils. You can spend a lot of time thinking you are digging coins but it's just old rust. In the freshwater areas several generations of wooden docks have been built over the same spot. The dock rots, the nails fall, the nails turn into giant rust spots that leach out to a foot in diameter, they sink, more nails fall etc. Ends up like a giant layer cake of nails several feet deep with rust frosting. So why detect around these old dock areas? Well because that's where the people were and they dropped the good stuff there.

In thinking through what I need, though not all inclusive, a detector it would ideally be.

1. Waterproof.
2. Very sensitive to small gold.
3. Perfect iron discrimination with no breakthrough.
4. Lightweight.
5. Immune to saltwater falsing & no loss of depth.
6. Ignore hot rocks.
7. Not affected by black sand, no loss of depth, no instability.
8. A battery that lasts forever.
9. A variety of coil size & types.
10. I like TID/VDI so it should have that also.

Already with my criteria it's obvious that no such detector exists. And looking at your list of detectors the saltwater component throws all of them overboard. People are not exactly tearing it up with the MXT on saltwater beaches.

I have ended up with a compromise which is where most of us end up. I have a couple of CZ-20's I use for under the water or wading up to my shoulders. They are always hip mounted because of their weight. It's a very deep detector for coins, but.......not very sensitive to small gold.....you have to use one a lot to not be fooled by deep iron......and it does suffer from some iron masking. On saltwater beaches, very deep but fooled by iron scale. Oh, and four 9V batteries at a whack, but about 50 hrs use.

And so to meet some of my other criteria what's out there? I considered one of ML's other BBS/FBS detectors but never really pulled the trigger as I liked the interface of the CZ's. Is there realistically any other mid-range detector out there other than an X70/705 that has an effective saltwater mode? Not that I can see. I'm not willing to kill myself digging with a PI, I'm in this hobby for the fun not an endurance test.

Aside from the Cz's, which I have, in the FT line is there a realistic saltwater capable detector? Not really, about the only person I've seen write about using an F75 as a saltwater beach machine is Jerry(Tinfoil).

In the White's line is the DFX, not exactly famous for saltwater prowess or price/ performance ratio. The Vision/Spectra/V3, still in development after release, but exactly how much depth over any CZ on the beach for how much? Once again cost/benefit?

Garrett, well......Infinium....here a hole.....there a hole.....everywhere a hole hole.:) meanwhile 300 bobby pins, 5 nickels, and a Chiropractor bill later.:lol: Tesoro......uh no. And I currently sort of have a Tesoro.....that sounds weird....but I have a Red Heat Tornado with a nine inch DD coil that is my beep dig machine. I have read various places that Vic Fiveash(RIP) sort of used a Tesoro as a starting point when he began making detectors. But on saltwater she dunna-like-it.

Now in the winter when I go to the beach, I go to the beach! Full day.......10 minute break in the AM, 20 minutes for lunch, 15 minute break in the afternoon. Nine to ten hours of detecting till I basically get beat down. What goes with me? Two CZ-20's, one 8 inch coil, one 10.5 inch coil, 2 X-Terras 70/705. I start by casing the beach with the CZ-20 10.5 inch and working the wet/damp till she gets too heavy to swing. Take morning break & switch off to the CZ-20 8 inch coil. Run that till it I get sore from holding the same angle on hand grip. Switch off to a Terra with the 10.5 MF or HF depending on how bad the black sand is. Just the change in weight distribution and hand angle gives me more hours detecting. When I get really tired I switch over to the 5 x 10 HF and head for the dry sand at the end of the day. Easy to swing the coil and digging is much easier. I'm also closer to my car at this point so I can drag my weary carcass to it before going face down in the sand.:laugh:

OK so what did the above detector choices provide me with? The CZ's are deep and handle the salt & black sand very well, but even small gold near the surface is going to be missed. There's more digging because they can be fooled by iron scale. The Terra's are not anywhere as deep in the wet/damp but use-able more than any other mid-range VLF. For the dry sand there's no comparison working the towel line, the HF Terra coils are killer on the gold. You are going to dig more aluminum than Alcoa but that's where the gold is!

On freshwater wading to waist height I'll use one of the Terra HF coils depending on iron density. If I get tired/sore from the hold angle I'll switch over to the Fisher Edge with six inch coil and go back over the trashier areas. Deeper water is CZ-20 territory. I'll also occasionally drag out the Red Heat Tornado for some beep dig just to make sure I'm not allowing my TID/VDI decisions to leave too much in the sand. It's a good cross check that keeps my ears honest.

I've gone into more detail because I believe any relic hunter, prospector, or park pirate, whether consciously or not, goes through a similar decision exercise. BUT....that exercise is based on their needs not mine. The Terras offer me the choice to configure them the way I see fit each application like no other detector I can see in this price range. And the detectors you listed are mostly landlubber prospecting machines.

And here's a little addendum. Sometimes in Winter hunting frozen lakes I end up with a 10ft x 10ft opening in the ice. If I slowly work it in C&T mode and clean it out then it's time to leave. But if I feel like continuing to detect I switch over to Prospecting mode. It's like having a virtual PI in your hands! Essentially you're in a beep dig mode with one hellaciously sensitive detector and can pull more targets to make the trip worthwhile.

And lastly is something I think everyone with a 3kHz coil should try some day, put the X70/705 in Prospecting mode.:surprised:

HH
BarnacleBill
 
I hear the excaliburs are great beach machines.I have a Quattro and havnt used it yet on the beach but hear there good on the beach.A dude i met at the beach a while back had one and he was plucken quarters dimes and nickels out of a beach that was heavaly covered with nails that was impresive. He also found a nice walker silver dollar when i was there.I hear the quattros are silver monsters. The xterras are really nice machines as well and love mine. I must admit ive been contemplaiting on a dfx or mxt they seem to be good machines. New whites looks amazing but pricey. Anyway good hunting to all .
 
A very interesting and colorful story Bill!! Yes CZ is a good machine for that, but yes I agree an Excalibur II is the one to use as the closest criteria to the perfect unit you want. OR a Tesoro Tiger Shark is very good on iron and also has a salt mode. Also if the Whites TDI PulseScan is set up right it can reject trash and pick up silver, but unfortunately not gold.
 
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