X-Terra 6" 18.75 khz DD coil first impressions

atomicscott

Bronze Member
Aug 18, 2011
1,564
1,055
Riverside CA
Detector(s) used
Current: Nokta Makro Simplex+, Teknetics Patriot, Fisher Gold Bug (original), GP Pinpointer (Garrett Clone) Lesche. Owned: Omega 8000, Minelab X-Terra 505, Fisher F2, Tesoro Vaquero, & Compadre, Whit
Primary Interest:
All Treasure Hunting
I know the 3 khz 6" Digger coil is the hot coil to have at the moment, especially when digging for silver coins. I haven't seen a lot of reviews on the 6" 18.75 khz DD coil, that has been available for awhile now. Being interested in prospecting and finding gold jewelry with my XT 505, I was compelled to try this coil. I also was hoping the better separation would be helpful in some of the trashier sites I hunt. I thought about the 10x5" 18.75 DD coil, but I wanted the option of using it at the beach, therefore it must be waterproof, which the 10x5 is not. I've only put about 12 hrs so far on this coil, but have a good sense of how well it works in the conditions in which I hunt.

Separation: There is an old home site that I have dated to the late 1800's that I have been gridding very slowly & methodically, with the 7.5 kHz 6" concentric coil (GB phase 13). The grid I started on, yielded the finds that helped to date the site: A shotgun shell from late 1800's & brass hourglass frame from turn of century era. Using the 18.75 6" khz coil in the same grid, I found a 1919 wheat and another copper penny (1971). Both jumped out of the surrounding trash. I was using all metal multi (99) tones. A couple days later, I tried the 18.75 coil at a local school (good moist ground, GB 25) that I hit a week previously with the 6" 7.5 khz (& many times with the 9" stock) and I found 19 coins with the HF coil, that I missed with the mid frequency coils. I believe the better separation (due to the DD coil) and increased sensitivity to smaller mass items (due to the higher frequency), helped to find these targets that the concentric mid frequency coils missed.
Depth: I was simply amazed at the depth of this small coil! At the old home site, the coins I recovered were about 4-6" deep, nothing unusual. It was at the school that I realized the power of this small coil. I found 2 dimes at 7". Then I had a solid mid-high tone, and ID# was 36. I dug the 7" of the Lesche blade, and figured it must be canslaw or something large, but I still had the same solid signal. I could not get a hit with my trusty (Centech, lol) pinpointer. I finally had dug the length of the entire Lesche other than about maybe an inch of the handle sticking out of the hole. Now I finally got a hit with the pinpointer and it was a 1970 copper penny at an honest 10"! Granted the penny isn't worth anything, but the depth on a conductor of the copper range is quite impressive in my book!

Pinpointing: I was purposely using the common DD 'heel/toe' method at first, then realized that the this coil really seemed to pinpoint in the center of the coil basically the same as the 6" concentric coil does. This made a zero learning curve in the pinpointing department.

Target bin/ID #'s: Ok, this is where you can get a feel of the difference in an MF coil and HF coil! I realized right away, that a dime tone that had an ID# of 36, was now a solid 39 with the 18.75 khz coil and the 36 was now a copper penny. Deeper quarters, instead of jumping from 39-42, were now jumping more from 42-45. I was getting more 48 ID#/tones, and some were dropping to a -9, but there were more solid 48 (that didn't bounce) hits than with the 7.5 coils. I did dig a few of the 48 tones, but they were deeper/larger and/or very rusty iron.

Pros: With the 18.75khz coil, I have dug many more pulltabs, & definitely more nickels than usual. They seem to lock on to the tones/ID#s better as well. I am pleased with this as I know this is a plus when looking for gold. I have found some small copper clothing snaps (approx. 1/4" diameter) that rang up solid copper pennies that I missed with the MF coils. Sensitivity to small objects is intense!

Cons: I need to be aware of the higher target bin/ID#s as the "Boy who cried wolf" always makes me nervous! If I give up on digging most of the highest tone (48) hits, will I eventually miss out on a Morgan silver dollar? For now, I will dig the highest tone/48, signals, at least if it's not big or real deep. Then maybe I can learn to discern the iron from the silver dollars eventually!

Overall, I really like this coil and will be using it exclusively, or at least until I can find a reason that my other coils will be an advantage
My average GB phase# out here is below 14, so I know I have an advantage with the DD coil in my ground. I'm excited to get out to the beach, as well as the goldfields in the desert, to see how well it handles the mineralization.
Hope this helps someone! HH, Scott
 

Last edited:

Bart@Big Boys Hobbies

Supporting Vendor
Supporting Vendor
Jul 24, 2005
4,602
1,226
Moore Oklahoma
Detector(s) used
Call for your Treasurenet special discount! Be sure to mention Tnet when you call!
Primary Interest:
Metal Detecting
I know the 3 khz 6" Digger coil is the hot coil to have at the moment, especially when digging for silver coins. I haven't seen a lot of reviews on the 6" 18.75 khz DD coil, that has been available for awhile now. Being interested in prospecting and finding gold jewelry with my XT 505, I was compelled to try this coil. I also was hoping the better separation would be helpful in some of the trashier sites I hunt. I thought about the 10x5" 18.75 DD coil, but I wanted the option of using it at the beach, therefore it must be waterproof, which the 10x5 is not. I've only put about 12 hrs so far on this coil, but have a good sense of how well it works in the conditions in which I hunt.

Separation: There is an old home site that I have dated to the late 1800's that I have been gridding very slowly & methodically, with the 7.5 kHz 6" concentric coil (GB phase 13). The grid I started on, yielded the finds that helped to date the site: A shotgun shell from late 1800's & brass hourglass frame from turn of century era. Using the 18.75 6" khz coil in the same grid, I found a 1919 wheat and another copper penny (1971). Both jumped out of the surrounding trash. I was using all metal multi (99) tones. A couple days later, I tried the 18.75 coil at a local school (good moist ground, GB 25) that I hit a week previously with the 6" 7.5 khz (& many times with the 9" stock) and I found 19 coins with the HF coil, that I missed with the mid frequency coils. I believe the better separation (due to the DD coil) and increased sensitivity to smaller mass items (due to the higher frequency), helped to find these targets that the concentric mid frequency coils missed.
Depth: I was simply amazed at the depth of this small coil! At the old home site, the coins I recovered were about 4-6" deep, nothing unusual. It was at the school that I realized the power of this small coil. I found 2 dimes at 7". Then I had a solid mid-high tone, and ID# was 36. I dug the 7" of the Lesche blade, and figured it must be canslaw or something large, but I still had the same solid signal. I could not get a hit with my trusty (Centech, lol) pinpointer. I finally had dug the length of the entire Lesche other than about maybe an inch of the handle sticking out of the hole. Now I finally got a hit with the pinpointer and it was a 1970 copper penny at an honest 10"! Granted the penny isn't worth anything, but the depth on a conductor of the copper range is quite impressive in my book!

Pinpointing: I was purposely using the common DD 'heel/toe' method at first, then realized that the this coil really seemed to pinpoint in the center of the coil basically the same as the 6" concentric coil does. This made a zero learning curve in the pinpointing department.

Target bin/ID #'s: Ok, this is where you can get a feel of the difference in an MF coil and HF coil! I realized right away, that a dime tone that had an ID# of 36, was now a solid 39 with the 18.75 khz coil and the 36 was now a copper penny. Deeper quarters, instead of jumping from 39-42, were now jumping more from 42-45. I was getting more 48 ID#/tones, and some were dropping to a -9, but there were more solid 48 (that didn't bounce) hits than with the 7.5 coils. I did dig a few of the 48 tones, but they were deeper/larger and/or very rusty iron.

Pros: With the 18.75khz coil, I have dug many more pulltabs, & definitely more nickels than usual. They seem to lock on to the tones/ID#s better as well. I am pleased with this as I know this is a plus when looking for gold. I have found some small copper clothing snaps (approx. 1/4" diameter) that rang up solid copper pennies that I missed with the MF coils. Sensitivity to small objects is intense!

Cons: I need to be aware of the higher target bin/ID#s as the "Boy who cried wolf" always makes me nervous! If I give up on digging most of the highest tone (48) hits, will I eventually miss out on a Morgan silver dollar? For now, I will dig the highest tone/48, signals, at least if it's not big or real deep. Then maybe I can learn to discern the iron from the silver dollars eventually!

Overall, I really like this coil and will be using it exclusively, or at least until I can find a reason that my other coils will be an advantage
My average GB phase# out here is below 14, so I know I have an advantage with the DD coil in my ground. I'm excited to get out to the beach, as well as the goldfields in the desert, to see how well it handles the mineralization.
Hope this helps someone! HH, Scott

Great report Scott! Keep us posted and updated!

Have you tried the 6" Coiltek digger coil too? I would like to hear your opinion. My customers love them!
 

id_au_digger

Greenie
Sep 3, 2013
19
2
Idaho
Detector(s) used
Gold Bug II, X-Terra 70, ACE 350
I picked up the 18.75 recently, but haven't played with it much. Your post is giving more confidence.. Was having a terrible time yesterday around a early 1900 store. MF driving me crazy with all the coin sounding aluminum trash(#36-46); walked away frustrated. Hope this DD works better in these type areas. Using X-terra 70. Any added advice?
 

Longhair

Hero Member
May 26, 2012
781
418
Backside Of Nowhere In Mid-Michigan
Detector(s) used
Fisher F2,
Fisher 1280X,
MineLab Xterra 705,
MineLab Explorer SE
Primary Interest:
All Treasure Hunting
SLOW DOWN!
The Xterra is a very stable running machine that works well in trash. The DD coil will help a lot, but the most common problem is swinging too fast.
 

OP
OP
atomicscott

atomicscott

Bronze Member
Aug 18, 2011
1,564
1,055
Riverside CA
Detector(s) used
Current: Nokta Makro Simplex+, Teknetics Patriot, Fisher Gold Bug (original), GP Pinpointer (Garrett Clone) Lesche. Owned: Omega 8000, Minelab X-Terra 505, Fisher F2, Tesoro Vaquero, & Compadre, Whit
Primary Interest:
All Treasure Hunting
SLOW DOWN!
The Xterra is a very stable running machine that works well in trash. The DD coil will help a lot, but the most common problem is swinging too fast.
Haha, you beat me to it LH! Of course I learned it from you and Randy in the first place! Slow it down in the trash, run 99 tones & try your hardest not to disc anything and be sure to check the target from different angles.
 

id_au_digger

Greenie
Sep 3, 2013
19
2
Idaho
Detector(s) used
Gold Bug II, X-Terra 70, ACE 350
Really tough learning to slow the sweep after learning on a Gold Bug 2. I have to try harder. Thanks guys.
 

OP
OP
atomicscott

atomicscott

Bronze Member
Aug 18, 2011
1,564
1,055
Riverside CA
Detector(s) used
Current: Nokta Makro Simplex+, Teknetics Patriot, Fisher Gold Bug (original), GP Pinpointer (Garrett Clone) Lesche. Owned: Omega 8000, Minelab X-Terra 505, Fisher F2, Tesoro Vaquero, & Compadre, Whit
Primary Interest:
All Treasure Hunting
Really tough learning to slow the sweep after learning on a Gold Bug 2. I have to try harder. Thanks guys.
Be sure to download Digger's (Randy Horton) ebook on the Minelab site 'Understanding your X-Terra'. This will help to see how great the X-Terra's technology really is.
Average sweep speed for the X-Terra is about 2.5 seconds per swing, it's not really very slow. The slower the sweep speed with any detector (especially in trash), the better the separation.
 

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