12x10 DD Bad air test?

[HateTabs]

Hey guys, I finally got the 12x10 coil for the Vaquero and did some air tests, I normally don't care about air tests but they are good to compare coils. I was kinda shocked that it did no better than my 5.75 concentric, I got it mainly for the coverage but I figured at least 1-2 inches more. They both hit a nickle at 10" and quarter at 9", that was at max sens and normal thresh. Is this normal or could I have one that is not so hot?
There is a wealth of knowledge on here and I appreciate everyone that takes the time to read and answer questions! Thank You

 

[MarkCZ]

My testing with different size coils on the Tejon didn't show enough difference in depth to even try and figure.
That's an odd thing about some of the Tesoro's as compared to other brands of detectors.
For this coming season I'm planning on staying with the 5"X 10" WS.

Mark

 

[Mega]

Sometimes bigger is not always better,i had one for a very short time duration but sold it on quickly as i found it was not only heavy but as you have found out not all that much better depth,of course on larger artifacts then you will find some improvement but on coin size items not a great amount but you will gain extra ground coverage.Its on larger targets that you will get much greater depth over a smaller coil.

 

[kaolinwasher]

Yep no better depth ,

 

[oneguy]

9"-10" is pretty respectable for any tector and Tesoros seem to air test closer to real world than say a Minelab? You might even do better in the ground? There's a fine line where larger coils fall off as far as depth/performance....depends on the machine/make....most coil manufacturers have all this figured out. 12" also isn't that big when it comes to larger coils but may be the largest your Tesoro is compatable with? You'll also get a little bit more coverage down deeper with the DD.

Go with it and see what it'll do in real world situations......you might like it

 

[BeyWolf]

I air tested the 5.75" concentric and 12x10" DD on my Tejon.
Using a nickel I got 9" on the small coil and 12" on the large coil.
I got a 2 inch difference using a quarter and I got similar results with other coins.

If you know someone else with a Tesoro detector, you could test your coils on that machine and maybe find the answers you're looking for.
Maybe it's not the coils or the detectors but the detector/coil combination.
Maybe some detector frequencies work better with certain coils.

That 12x10" DD weighs almost twice as much as the 5.75" and I'm not very happy that I bought it even with that increase in depth.
I would really like to know how the 10" Elliptical Widescan coil compares to the 5.75" coils for weight, coverage and target sounds.

 

[MarkCZ]

I air tested the 5.75" concentric and 12x10" DD on my Tejon.
Using a nickel I got 9" on the small coil and 12" on the large coil.
I got a 2 inch difference using a quarter and I got similar results with other coins.

If you know someone else with a Tesoro detector, you could test your coils on that machine and maybe find the answers you're looking for.
Maybe it's not the coils or the detectors but the detector/coil combination.
Maybe some detector frequencies work better with certain coils.

That 12x10" DD weighs almost twice as much as the 5.75" and I'm not very happy that I bought it even with that increase in depth.
I would really like to know how the 10" Elliptical Widescan coil compares to the 5.75" coils for weight, coverage and target sounds.

The 5"X 10" LIKES gold! and seeing how I no longer have the little 5.75 WS I can't tell you the weight difference? But, my Tejon really likes the 10" elliptical WS coil. In my earlier post I added that coil test results chart which at the bottom has a score total. My brother Ron (forum member WV62) does these charts.
In the chart you have different coils across the top,
different items down the left side,
Air test in inches out to the right from each item and under each coil.
Across the bottom each column for each coil is totaled, that works out to an overall best average for the coils. The 10"X 5" scored 55.

I had a 10"x 12" for a short time but where I hunt and what I hunt I opted to keep and make the 10"X 5" my main Tejon coil.

Mark

 

[BeyWolf]

Thank you Mark for the information on the 5"x10", I plan on getting one this spring.

I hope HateTabs gets good use from his 12x10.
I don't like using mine for coins and jewelry.

 

[Furious T]

Air testing is good to compare coils, in the air. It is on the ground that you can appreciate the difference between a concentric coil and a DD coil. In moderately mineralised soil, a concentric coil should go deeper than a DD coil of about the same size, on any detector. It is when you get onto highly mineralised soils or saltwater beaches that a DD coil will outshine a concentric coil for depth, ie, it can handle the tougher conditions better, primarily because on a DD coil the "face" of the detecting surface of the coil is more suited to these tougher conditions than that of a concentric coil.

I have compared concentric coils in air tests with each other, and have found the information I obtained to be helpful, but I would not even bother comparing a DD coil and a concentric coil in an air test. But that's just me. HH

 

[MarkCZ]

In my results I've found that air test depth is ALWAYS greater than actual in ground results EXCEPT for items that halo, (rust) like Iron. I've gotten better results with DD coil vs concentric with the exception of rusty crown bottle caps seems fool the detector more.

Mark

 

[HateTabs]

Thanks everyone for the replies. That makes me feel better knowing that it's not a dud. I got the coil used so I am not out that much if I don't like it, it will mainly be used for beach hunting and open fields.

One more thing I am curious about, I read and watch videos of other mfg. detectors getting 12-14 inch air tests on coin size targets, if that is so how does it translate to in ground depth? I know mineralization plays a big role in it but are some detectors better in ground? Say my Vaquero tests a nickle at 10" and brand x tests at 13" does that automatically make brand x the deeper detector in ground? I know a lot of factors are involved there. Has anyone ever had a detector that air tested great but was not as good in ground as say the one that did not test as deep? Sorry for rambling, just things I think about.

 

[oneguy]

just the opposite with Minelab.....they sometimes don't air test well but that all changes when in the field usually. Your 9-10" is plenty and if you hunt in the dirt that's more than enough work when you start chasing any deepies....lol

 

[TallTom]

Exactly how did you do your air test? Indoor or outdoor? In your back yard near your power lines?
Horizontally or vertically? And how did you set your ground balance?

I discovered I got mediocre results with several detectors doing horizontal tests (that is, with the coil
aimed NOT at the ground, but parallel to it) in my back yard. Especially during some times
of the day, there is a lot of EMI to interfere with signals, apparently from my power lines and my
neighbor's, plus various electical appliances, etc. And I ignored the ground balance on my Vaq,
since I didn't know what to set it to when I wasn't pointing at the ground.

After reading some expert advice, I decided to test differently. I went to a large park that seems to
be nowhere near any EMI that would cause problems. I picked an open area and checked
in all metal that no metal was in the ground, and carefully ground balanced. Then I laid out
my test coins, one by one.

I swung my coil above each test coin, trying to carefully measure the distance between
the coin and the coil above it. This would have been easier if I had someone helping me, but
I think I was pretty accurate. (I pounded an all-wood ruler into the ground near the coin
and eyeballed the height while kneeling on the ground and swinging the coil above the coin. It was
awkward, but it seemed to be consistent.)

The results were much better than I got from my air test at home. I assume if the mineralization
was worse in the park's dirt, I might have done worse. I will try to find my results, but as I recall,
the 12x10 DD coil typically got 0.5 to 1.5 inches better "depth" (height) than the stock 9x8 concentric coil
when tested this way in the park. Anyway, it was enough of a difference for me to decide I was
getting better depth with the 12x10.

I'll be curious to hear your results (or anyone's) if you try a similar approach.

 

[MarkCZ]

Exactly how did you do your air test? Indoor or outdoor? In your back yard near your power lines?
Horizontally or vertically? And how did you set your ground balance?

I discovered I got mediocre results with several detectors doing horizontal tests (that is, with the coil
aimed NOT at the ground, but parallel to it) in my back yard. Especially during some times
of the day, there is a lot of EMI to interfere with signals, apparently from my power lines and my
neighbor's, plus various electical appliances, etc. And I ignored the ground balance on my Vaq,
since I didn't know what to set it to when I wasn't pointing at the ground.

After reading some expert advice, I decided to test differently. I went to a large park that seems to
be nowhere near any EMI that would cause problems. I picked an open area and checked
in all metal that no metal was in the ground, and carefully ground balanced. Then I laid out
my test coins, one by one.

I swung my coil above each test coin, trying to carefully measure the distance between
the coin and the coil above it. This would have been easier if I had someone helping me, but
I think I was pretty accurate. (I pounded an all-wood ruler into the ground near the coin
and eyeballed the height while kneeling on the ground and swinging the coil above the coin. It was
awkward, but it seemed to be consistent.)

The results were much better than I got from my air test at home. I assume if the mineralization
was worse in the park's dirt, I might have done worse. I will try to find my results, but as I recall,
the 12x10 DD coil typically got 0.5 to 1.5 inches better "depth" (height) than the stock 9x8 concentric coil
when tested this way in the park. Anyway, it was enough of a difference for me to decide I was
getting better depth with the 12x10.

I'll be curious to hear your results (or anyone's) if you try a similar approach.

Air testing anywhere there is HIGH EMI is just like hunting an area that's HIGH in EMI. From around 5:00am until around 6:20pm I could hunt my front yard with the Vaquero, at 6:20pm its like the detector just broke! with any setting of any control it would sound off on any piece or spec of metal in the ground!, from a rusty staple from a office stapler to tiny finishing nail!. So, it was impossible to hunt or air test in these conditions.

Ground balance is a BIG deal with air test! seeing how its only used to cancel out ground mineral effects, there isn't anything in the air to cancel out, nor is there anything in the air to effect the target response, as long as EMI isn't an issue.

In almost every case you'll get a little greater depth with air test than actually in the ground (except for halo of rusty iron).

In most air test people seem to set them up with a little bit GB just to not be at an extreme adjustment, but there is nothing to cancel out! so there is nothing in the way.

Mark

 

[HateTabs]

It's funny what you posted TallTom as I have just got back from testing in a different place, it seems that the 12x10 is LOT more sensitive to EMI than my concentrics and I must have more around the house than I realized. I moved as far away as I could from EMI sources, ground balanced and tested horizontally on the ground, I saw about a 2-2 1/2 inch difference with all coins. One more thing I noticed with the 12x10 is it does not work as good around trash as the concentrics, I know part of it is the size but if you lay a coin down with a nail on top it nulls the coin where as the concentrics can hit it. In open areas though the 12x10 is going to be a keeper! Thanks again everyone!

 

[oneguy]

One more thing I noticed with the 12x10 is it does not work as good around trash as the concentrics, I know part of it is the size but if you lay a coin down with a nail on top it nulls the coin where as the concentrics can hit it.

Is this your first experience with a DD coil..???? Just curious. If it is....they are a different beast altogether than a concentric. You really have to work a DD coil....both for PPing and isolating the target. They take a little bit more work but you are also covering a bit more ground on the deeper end of your coverage (the benefit) so isolating and PPing are harder to do especially if trash is involved. So you are back to the ol trade off thingy. Better coverage down deeper but you may also be detecting more possible junk. With a DD coil it's pretty important to do a circle around your target or at least check it from 90 degree angle? As far as your coin nulling with the iron on top goes....usually a 90 degree turn will let you hear the coin depending on the orientation of the coin/nail. I kinda look at it like slicing a pizza....if your machine is worth it's salt it'll give you a decent hint, then it should pick up the coin better with the junk in there also once you find the right angle....try and isolate, then wiggle back and dig. If the area is so junky that isolating and PPing are too hard to do....time to whip out the smaller coil or go back to your concentric?

Get that thing out in the field and see what it'll do? If you are not familiar with DD give it some time to learn what it can and can't do? I'll guarentee that you will find locations where it'll out perform for you and there will be places where you'd prefer the concentric. Just another tool for job that has it's place.......

 

[MarkCZ]

It's funny what you posted TallTom as I have just got back from testing in a different place, it seems that the 12x10 is LOT more sensitive to EMI than my concentrics and I must have more around the house than I realized. I moved as far away as I could from EMI sources, ground balanced and tested horizontally on the ground, I saw about a 2-2 1/2 inch difference with all coins. One more thing I noticed with the 12x10 is it does not work as good around trash as the concentrics, I know part of it is the size but if you lay a coin down with a nail on top it nulls the coin where as the concentrics can hit it. In open areas though the 12x10 is going to be a keeper! Thanks again everyone!

Generally speaking as you increase the size of the coil the more EMI can be a problem. If its real trashy areas or areas with lots of EMI smaller coils tend to lead to more stability with the detector. The 12"X 10" is a LARGE coil, so its a LARGER antenna for EMI, being LARGER means if they're is a lot of trash in the area then that puts MORE items under the coil at one time for the detector's circuits to process.

Mark

 

[HateTabs]

Oneguy it is my first experience with a large DD coil, I had a small 4x6 DD with a previously owned White's M6. Thanks MarkCZ that is what I am finding out, I didn't realize there would be that much difference between a concentric and DD coil as far as EMI is concerned. That is part of the fun I guess, always learning something!

 

[TallTom]

Don't forget you can try the two alternate frequencies on the Vaq when you are getting EMI.
Sometimes they can reduce the problem a little.

 

[oneguy]

Oneguy it is my first experience with a large DD coil, I had a small 4x6 DD with a previously owned White's M6.

Yeah....give that big DD a chance and get to know it, it has it's place! I also prefer the smaller DD's as the big ones can be some work PPing and isolating. With that said....I did go out today with a 15" on and snagged some nice deep oldies in a moderatly trashy area. Like I said...you gotta work em but they can reward you nicely in certain situations. You can check em out if you want on the etrac forum....

good luck with it..........