Will a Larger Coil Cover MORE Area?

[Capt. Morgan]

I just always looked as it like this:
DD": an open book
Concentric: a cone

Now if you compare an 11" DD that only goes 10" deep because of the "missing tip"
vs. a 10" concentric. I would still say that a DD scans more ground.

 

[Wot305]

I just always looked as it like this:
DD": an open book
Concentric: a cone

Now if you compare an 11" DD that only goes 10" deep because of the "missing tip"
vs. a 10" concentric. I would still say that a DD scans more ground.

Then you may have to change you're look to this:

Concentric: a cone
DD: a cone without It's tip.

Assuming a coin sized signal was in quiet non junky ground at 10", and your F2 managed a hit on it with the 11"DD elliptical, a 10"round concentric would hit better, and see more ground.
If it was an 11" DD round coil on another unit, and that unit could also run an 10" concentric, the concentric would still "see" more ground.
The only extra ground either an 11"DD elliptical or round would see, compared to a 10" concentric, would be in the extra inch in length, and then only near the surface.

 

[TN_INDIAN]

interesting i just got the 10in round coil and was thinking bout getten the 12in tornado dd coil next yr for the f2 but idk now.....I assumed that the DD coils was like a open book as well.

 

[gameoftag]

no expert, as I have only had a DD coil for a couple months now, but the u shaped diagram seems to be accurate. The DD does not appear to detect in a cone shape at all. In fact, you can find a deep coin with a DD without pinpointing by simply wiggling the coil back until the signal disappears. I dig where the tip was and can locate the coin right there no matter how deep. If it were a cone shape, wouldn't the deep coin signals die off before they reach the edge of the coil? Goes4ever has a great video on this here:
http://goes4ever.mymdforum.com/videos/

This works on deep coins too, so the cone theory doesn't make sense to me.

All I know is since I changed from concentric to DD, I have revisited a couple spots I have been over many times with the concentric and every one of those places, I have found coins at every single spot that I missed with the concentric. I have found coins deeper than I ever got with my concentric, and I have found coins among trashy areas that I was unable to find anything before.

I will never go back to concentric and my experience says a DD coil covers way more ground more thoroughly, gets better depth (even on the edge of the coil), and the target separation is amazing. I'm finally at one with my machine.

 

[itsaring!]

99% of my sites are pulltab & iron infested & I find quarters just fine with the big coil... Maybe its just your machine...

No,it's why they invented sniper coils

 

[Terry Soloman]

Then you may have to change you're look to this:

Concentric: a cone
DD: a cone without It's tip.

Assuming a coin sized signal was in quiet non junky ground at 10", and your F2 managed a hit on it with the 11"DD elliptical, a 10"round concentric would hit better, and see more ground.
If it was an 11" DD round coil on another unit, and that unit could also run an 10" concentric, the concentric would still "see" more ground.
The only extra ground either an 11"DD elliptical or round would see, compared to a 10" concentric, would be in the extra inch in length, and then only near the surface.

Pretty good discussion so far! A couple of illustrations to add.

 

[TN_INDIAN]

so the double d has like a laser reading and not the cone shaped???

 

[Finnerman]

From personal observation, I think the front view of a DD might look more like this. just a thought.

 

[Burbank Bob]

I've got a 13 inch DeTech Pro Coil that works very well even in trash with great target separation and a lot of depth, but I think it suffers in extreme trash. GStout76 can pipe in if he reads this as it was his coil.

Got a NEL Sharpshooter coil in the mail now. Supposed to have nearly the same depth as the big one with better trash separation.

I'll give you the report soon, but honestly, the differences in coils may very well be the people swinging them. Greg may can hear something in that ETrac and big DeTech coil that I have not learned to listen for and glean silver from the trash.

I think practice does make perfect.

 

[Wot305]

no expert, as I have only had a DD coil for a couple months now, but the u shaped diagram seems to be accurate. The DD does not appear to detect in a cone shape at all. In fact, you can find a deep coin with a DD without pinpointing by simply wiggling the coil back until the signal disappears. I dig where the tip was and can locate the coin right there no matter how deep. If it were a cone shape, wouldn't the deep coin signals die off before they reach the edge of the coil? Goes4ever has a great video on this here:
http://goes4ever.mymdforum.com/videos/

This works on deep coins too, so the cone theory doesn't make sense to me.

All I know is since I changed from concentric to DD, I have revisited a couple spots I have been over many times with the concentric and every one of those places, I have found coins at every single spot that I missed with the concentric. I have found coins deeper than I ever got with my concentric, and I have found coins among trashy areas that I was unable to find anything before.

I will never go back to concentric and my experience says a DD coil covers way more ground more thoroughly, gets better depth (even on the edge of the coil), and the target separation is amazing. I'm finally at one with my machine.

Hi Gameoftag.

The link you posted is a perfect example.
Notice the depth the planted coin was at after he dug the plug and used his pinpointer. The coin was around an inch under the ground from before he dug.

It would give a full signal along the centre of a DD coil as it stays within the cone for the entire length. Even the sensitivity of the coil reacts afterwards when the coin is an inch in Front of the coil when on top of the ground.

The pic below is what happened in the video, along with the real scenario on how a DD behaves.

 

[Wot305]

keep photos online

 

[Wot305]

Let's all take a birds eye, or rather a detectorists eye, at the DD pic that Terry supplied. Come on and walk around the other side of it with me.

Let's make it an 8". The nail size does not correspond with the nail size in Terry's pic, as it would be around three inches long in that one, and makes this pic look like It's under a 14.5" coil, but it does not matter.

Sweeping from the left hand side of us - over to the right, our first signal at 1" is the nail, followed by the coin....but only because it is at 6" directly beneath central at depth, then the cap hits at around an inch. All three signals are within the DD's cone, because the nail and coin are shallow, and the coin is at the sweet spot.

The green coins at 6" have not made a sound, not even a threshold murmer, as they are out of the cone.

upload

 

[Wot305]

picture hosting

 

[Wot305]

This scenario on some detectors would not let the users of a sour unit respond with enough information for us to establish the targets with an 8" coil. I hope you aren't using one of those detectors.
Out of my units and coil combos, if I had to use an 8" over this scenario, it would be a concentric! Why? ....because the DD is missing the tip of It's cone, and the concentric would give me a much cleaner hit on the coin, along with less sound on the nail and cap.

 

[Wot305]

From personal observation, I think the front view of a DD might look more like this. just a thought.

Sorry Finnerman. Worth a punt though...

 

[Wot305]

keep photos online

 

[itsaring!]

The post does say allow a newby to cover more ground with a bigger coil.Now that statement is true when you think about it.Most is not gonna run a machine hot and swing too fast.So they are gonna be clearing out all the shallower stuff.Can someone diagram a Whites bigfoot coil comparison

 

[itsaring!]

Read 'em and weep fellas When you switch on all metal the front half of the coil is all that works.Pretty cool!

 

[gameoftag]

Hi Gameoftag.

The link you posted is a perfect example.
Notice the depth the planted coin was at after he dug the plug and used his pinpointer. The coin was around an inch under the ground from before he dug.

It would give a full signal along the centre of a DD coil as it stays within the cone for the entire length. Even the sensitivity of the coil reacts afterwards when the coin is an inch in Front of the coil when on top of the ground.

The pic below is what happened in the video, along with the real scenario on how a DD behaves.

I covered that in my response when I said it works on deep coins too. Dug a merc dime 6" down and pinpointed it the exact same way as G4E in his video. Cut the plug at the end, and it was exactly where I thought it would be. I'm not saying your wrong, I'm just saying that my experience has been the same no matter how deep the coin is, so how does a DD sound off on the edge of the coil on a deep coin if it is detecting a cone shape?

You have made it clear you don't like the DD, but I'm telling you, nothing you have said matches what I have seen in the field. You say you have tested many of these coils and I have only had one for 2 months, so I'm not claiming to know what I'm talking about, but I bought the coil for greater depth and because my research showed it detecting in a U shape along the narrow band in the center of the coil. When I bought it, and tested it, it appeared to do what It claimed to do. Now I don't know, so I'll have to try it with your thoughts in mind.

 

[AIRFORCEMIKE]

no expert, as I have only had a DD coil for a couple months now, but the u shaped diagram seems to be accurate. The DD does not appear to detect in a cone shape at all. In fact, you can find a deep coin with a DD without pinpointing by simply wiggling the coil back until the signal disappears. I dig where the tip was and can locate the coin right there no matter how deep. If it were a cone shape, wouldn't the deep coin signals die off before they reach the edge of the coil? Goes4ever has a great video on this here:
http://goes4ever.mymdforum.com/videos/

This works on deep coins too, so the cone theory doesn't make sense to me.

All I know is since I changed from concentric to DD, I have revisited a couple spots I have been over many times with the concentric and every one of those places, I have found coins at every single spot that I missed with the concentric. I have found coins deeper than I ever got with my concentric, and I have found coins among trashy areas that I was unable to find anything before.

I will never go back to concentric and my experience says a DD coil covers way more ground more thoroughly, gets better depth (even on the edge of the coil), and the target separation is amazing. I'm finally at one with my machine.

Josh, the DD is fit much better for our soil...it really comes down to that. The concentric coils I always have had issues with here. Good thing your went back to your previous areas to re-track your steps..NICE JOB!!