coil selection is confusing help!

[mitwes56]

I have been up and down on this issue for awhile now. I have read post from some that say the beachs in florida are so neutral that alot of metal detectors will not even ground balance you just go to the factory preset and hunt. Other users along the east coast seem to have a black sand problem with high mineralization. In steps the dd coils to save the day! I would like to add a 10.5 dd coil to my xterra arsenal but what frequency? I dont live on a beach but I do visit a few thru the summer. the 18.75 freq is designed to work on small objects in ground with a lot of minerals and picks up gold jewlery better I suppose. But some swear by the 7.75 frequency coil in dd at the beachs also. I have read all the great faq's. I would like to use the coil in my regular daily hunting also on sports fields , old homesites etc. I already have the 6 dd hf coil also. LOve the little guy but on a beach I think it would be over whelmed with the area to cover. So anyone living around a coast line that has used the dd coil in 10.5 inch I would appreciate your opinions on what frequency you used and how you liked it.

 

[thedeserttortoise]

Hi Mitwes56. I just got off the MLO forum and was kind of wondering the same thing. There was a good disscussion on all the coils available. In a nutshell they had twoo rather inportant points. One, go with a DD if your in high minearlization. Two, higher freq equals more sensetivity, lower frequencys equal more depth. The average concensus seemed to favor the mid freq 10 1/2 inch coil in DD for general hunting including beach's. The 18.75's seem to still rule the roost for small gold. For jewlery, coins and other like size items they still favored the 7khz, 10 1/2. It had enough impact on me to convince me to try the 7 khz 10 1/2 DD coil. Just ordered one from Kellyco. I'm going to do a little video comparision between the Etrac and the Xterra on a 2 or 3 gram peice of gold as soon as all the coils arrive. I'll post a message in both forums when its done. This is leading me to possibly include coin and jewlery in the test too. It all depends on the time...gold for sure, as thats what I'm after.

 

[mitwes56]

I will be waiting for your test after you recieve the 10.5 dd in medium frequency. I am also curious as to how nose heavy it will be from the factory coil.

 

[thedeserttortoise]

I should get all my new coils next week. I just received permision to search one of the business parking lots in town (its all gravel). The owner said he knows the business goes back to the 40's and since the business is on the corner of the main drag I suspect their might be something there. The town has been frequented by settlers since the late 1800's. It gained population around 1916 and continued to grow since then. Its about 1 1/2 blocks from Geronimo Hot Springs, an artesian hot spring frequented by indians, early settlers, and calvary units since the late 1800's. I intend to do an initial search until I reach five targets with the X-Terra and mark those locations with a flag. I'll then do the same with the E-Trac. After that, I'll go over each target with the full asst of coils and detecters, detailing what targets are active on each. Once thats complete, I'll dig each to determine depth and target composition. I hope this works out. I'll video the works and share it with you when I'm done. I just have to wait until a Sunday or holiday when he's closed. I only hope its native dirt and not back fill. I might go over there in the next couple of days and dig a couple of test targets to see. I will have all three concentrics (3,7,and 18.75Khz), the elipitical 18.75Khz DD, the 6" 18.75Khz DD, and the 10 1/2" 7 Khz DD for the X-Terra. I'll have the 5" DD, 6" DD, a 15" WOT, an 15 X 12 SEF, and the stock Pro coil for the E-Trac. The week after, I should get out to the goldfields to test the Xterra against the Etrac on a gold nugget. Should be fun and informative.