CoilFisher
Hero Member
- Jul 17, 2011
- 948
- 250
- Primary Interest:
- Metal Detecting
Any opinions on this one? (Constructive ones 
):
):F-75 6.5" concentric vs 5" DD Coil
- Thread starter CoilFisher
- Start date
Charlie P. (NY)
Gold Member
- Feb 3, 2006
- 13,019
- 17,177
- Detector(s) used
- Minelab Musketeer Advantage Pro w/8" & 10" DD coils/Fisher F75se(Upgraded to LTD2) w/11" DD, 6.5" concentric & 9.5" NEL Sharpshooter DD coils/Sunray FX-1 Probe & F-Point/Black Widows/Rattler headphone
- Primary Interest:
- Metal Detecting
Been playing with the 6.5" concentric and it's a great coil. I'm amazed the depth is still good. Haven't tried the 5" DD, but I also haven't taken off the 6.5" oval since I added it.
Last edited:
N2CU
Full Member
- Feb 13, 2011
- 136
- 7
- Detector(s) used
- Minelab Equinox 800, Fisher F70, Pro-Pointer
- Primary Interest:
- All Treasure Hunting
I have a F70 that came with the 10" concentric. Bought a 5" DD and didn't take it off all last year. I traded the 10" for a 11"DD and used it for a while. Put the 5" back on today for a short hunt and was reminded how light it is and so easy to swing. Can't say I've lost any depth vs. the 10" and it sure works great in trashy areas.
pinpointer999
Jr. Member
- Aug 22, 2015
- 30
- 24
- Detector(s) used
- Fisher F75 Ltd.
Fisher CZ21
Fisher CZ6a
Makro CF77
Minelab Musketeer XS
Whites DFX
Whites MX5
Whites IDX Pro (Mr. Bill mod.)
White's 5900/di Pro Plus (Keith Southern mod)
White's 6000/di Pro
- Primary Interest:
- All Treasure Hunting
The main difference I find is that the DD gives false high readings in the 70s and 80s on rusty bottle caps.
The 6.5 concentric will register much lower out of the coin range and makes disc. more effective.
Since switching to the concentric in trashy bottle cap infested areas, i have almost totally eliminated
the bottle cap problem i had when using DD coils. I am looking to add the 10" elliptical concentric to my
gear to get better depth, and at the same time eliminate rusty bottle cap false high VDI readings.
The 6.5 concentric will register much lower out of the coin range and makes disc. more effective.
Since switching to the concentric in trashy bottle cap infested areas, i have almost totally eliminated
the bottle cap problem i had when using DD coils. I am looking to add the 10" elliptical concentric to my
gear to get better depth, and at the same time eliminate rusty bottle cap false high VDI readings.
Last edited:
DeepseekerADS
Gold Member
- Mar 3, 2013
- 14,880
- 21,738
- Detector(s) used
- CTX, Excal II, EQ800, Fisher 1260X, Tesoro Royal Sabre, Tejon, Garrett ADSIII, Carrot, Stealth 920iX, Keene A52
- Primary Interest:
- Other
digger27
Bronze Member
- May 18, 2011
- 1,506
- 3,225
8
I have the 10" standard concentric, the big 11" DD F75 and the 5" DD for my F70 and I use and love all 3 types.
The 11" gets scary deep, the concentric is great under most circumstances and does deal with the bottle cap problem easily, the 5" is surprisingly deep and my choice in heavy trash and iron infested sites.
All 3 have found me mucho coins both old and new and tons of silver plus many gold targets.
I use the DD's more than the concentric and hunt public parks loaded with pop tops and use a technique that makes those pop tops a total non issue.
If you try this you will find you can efficiently and easily eliminate 95% or a bit more of these hated things and make hunting trashy sites with DD's, (if you choose to do this for whatever reason), just as frustration free as when you use concentrics.
This technique is called rimming and trust me it works on most shallower tops at 6" or less in depth.
I have dug hundreds and hundreds of pop tops experimenting to make sure it works and now I confidently dig very few.
When you come across a high tone, high number coin like signal that is actually a pop top just make some quick side to side movements over the target as you pull back the coil.
When the front rim gets over the target and moves just a hair past the numbers will drop.
They might drop to the 40's or 30's, sometimes they will drop all the way down to iron but there will be a drop.
Coins never do this, most pop tops will.
Very flat, rusted older style caps laying flat in the soil will still act like coins and won't usually drop and there are some of these out there but really not all that many, most others will drop to lower areas.
Using low disc you can see this drops easily, using high disc, I have done a few hunts recently with disc set at 50, I have found I still get high tones and high numbers and can't see the drop but they don't repeat so I can still tell but I usually prefer using lower disc to see the drop.
Using this technique has turned hunting in my trashed out public parks using DD coils from a nightmare into a pleasure.
Try it.
I have the 10" standard concentric, the big 11" DD F75 and the 5" DD for my F70 and I use and love all 3 types.
The 11" gets scary deep, the concentric is great under most circumstances and does deal with the bottle cap problem easily, the 5" is surprisingly deep and my choice in heavy trash and iron infested sites.
All 3 have found me mucho coins both old and new and tons of silver plus many gold targets.
I use the DD's more than the concentric and hunt public parks loaded with pop tops and use a technique that makes those pop tops a total non issue.
If you try this you will find you can efficiently and easily eliminate 95% or a bit more of these hated things and make hunting trashy sites with DD's, (if you choose to do this for whatever reason), just as frustration free as when you use concentrics.
This technique is called rimming and trust me it works on most shallower tops at 6" or less in depth.
I have dug hundreds and hundreds of pop tops experimenting to make sure it works and now I confidently dig very few.
When you come across a high tone, high number coin like signal that is actually a pop top just make some quick side to side movements over the target as you pull back the coil.
When the front rim gets over the target and moves just a hair past the numbers will drop.
They might drop to the 40's or 30's, sometimes they will drop all the way down to iron but there will be a drop.
Coins never do this, most pop tops will.
Very flat, rusted older style caps laying flat in the soil will still act like coins and won't usually drop and there are some of these out there but really not all that many, most others will drop to lower areas.
Using low disc you can see this drops easily, using high disc, I have done a few hunts recently with disc set at 50, I have found I still get high tones and high numbers and can't see the drop but they don't repeat so I can still tell but I usually prefer using lower disc to see the drop.
Using this technique has turned hunting in my trashed out public parks using DD coils from a nightmare into a pleasure.
Try it.
Last edited:
- Jun 16, 2014
- 11,876
- 17,930
- 🥇 Banner finds
- 1
- Detector(s) used
- F75 LTD, 1280X Aquanaut, & a Patriot (back-up/loaner)
- Primary Interest:
- Metal Detecting
Thanks for the advice digger 27, I will try this the next time I go to one of my public sites.
pinpointer999
Jr. Member
- Aug 22, 2015
- 30
- 24
- Detector(s) used
- Fisher F75 Ltd.
Fisher CZ21
Fisher CZ6a
Makro CF77
Minelab Musketeer XS
Whites DFX
Whites MX5
Whites IDX Pro (Mr. Bill mod.)
White's 5900/di Pro Plus (Keith Southern mod)
White's 6000/di Pro
- Primary Interest:
- All Treasure Hunting
Awesome advice digger27... you have just given me the most helpful advice i have ever gotten for my F75.
You may have just saved my sanity.
HH
You may have just saved my sanity.
HH
Last edited:
digger27
Bronze Member
- May 18, 2011
- 1,506
- 3,225
Awesome advice digger27... you have just given me the most helpful advice i have ever gotten for my F75.
You may have just saved my sanity.
HH
Too late for me I am afraid, that ship sailed long ago, but I am happy to help someone else.
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