Teknetics gamma 6000 coil question.

[Garbagebill]

Hi all,

I'm new to this hobby, still waiting for my MD to arrive. Was wondering a couple things. This comes with an 8" coil. I've read on here where people have purchased 5" and 11" coils also. I guess my question would be, what does the 5" coil do? What does the 11" DD do? For that matter what does my 8" coil do?

A little info on me in case that becomes important in the answering of these questions.
I live around Sacramento California. As far as where I live, the soil is mostly soft regular soil. If I go a half hour to the west I'm in SF at the beach if I go 30 minutes to the east I'm in the mountain which can be hard as rock and also very deep red clay. As far as I know, I'll be doing most of my detecting in the soft regular soil. But i will also love to try beach detecting, and I'm sure I will also be up in the mountains a fair share too. As of now, mostly coin hunting. BUT I'm also a guy who will get a kick out of pulling a 1901 door knob out of the ground too. So I really think as I learn my machine better I'm going to be into it all. Relics, jewelry, coins, hell anything and everything. So, I'm not sure anything I've just said means a damn thing hahaha! And advice will be appreciated. Thanks, Bill

 

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[locater]

Hey Bill, a 5" coil is usefull in trashy areas where you have a lot of junk mixed in with the good targets. The smaller coil allows you to get better separation between the targets that are close together. They are more sensative to smaller targets also, but give less depth.
The 11"DD coil gives much better depth and coverage. My first detector was a BH Platinum, which is nearly identical to the Gamma, with a few minor tweeks. It came with a stock 8" concentric coil, which I quickly changed to an 11" DD. The change was literally like opening the basement door, it gave much more depth.

The signal output pattern of the stock 8" concentric coil looks like a cone shape, wider at the top and narrowing as it goes down. Because of this pattern it is recommended that you overlap your coil sweeps by as much as 50% for effective coverage. The signal output of a DD coil is more a solid beem down the middle of the coil, with a more even pattern as it goes deeper. It requires very little coil overlap per sweep, which gives a DD coil much more effective coverage.

The general rule on coil size is, the larger the coil the more depth, but less sensitivity to smaller objects. Reverse that with smaller coils, less depth, more sensitive to smaller objects.

Hope this was helpful. Good Luck!

 

[Garbagebill]

Thanks locater! Makes sense now! I think I'd better get me and 11" DD just wonder if it fits on my lower pole or if I need to buy a new lower pole? I read somewhere that sometimes you have to make sure the bigger fits on the adapter where the pole meets the coil? Any idea?

 

[locater]

Hey Bill, if you should get the 11"DD, fit to the lower shaft should be no problem. Many people, me included, get a new lower shaft with the new coil. That way if you should decide to switch coils for different conditions, all you have to do is disconnect the coil wire at the control box and change the lower shaft with the coil connected, pretty easy. In my case when I bought my DD coil, the retailer had tallman lower shafts on sale, which was good for me as I have long legs.

Being as you are new tho the hobby, I suggest you check out some of the websites for new detectorists. They have a wealth of information that shortens the learning curve, provide a lot of good tips and knowledge. I am sure you will like your Gamma, it's a good machine for a beginner! It has a lot of features of more expensive machines, and is pretty easy to operate, with good performance. Hook it up to that 11" DD and it will maximize it's performance.

I see you are planning on detecting in a variety of conditions including beach detecting. You should be aware that a single frequency detector such as the gamma will not operate well, in wet salt sand. It will work fine in wet/dry fresh water sand, or dry salt water sand. The highly conductive nature of wet salt sand makes it extremely difficult for single frequency VLF detectors to operate smoothly. Make sure wherever you detect to ground balance the machine as needed. Enjoy!!

 

[Garbagebill]

Thanks locater! I didn't know that about salt water areas. Good to know! And yeah I think it would be easier to change shafts instead of having to disassemble the coil and control box fitting. I'm still trying to figure out my machine, seems it just wants to chirp constantly. And I dig and still don't find anything so I've got a long way to go yet! Lol been watching some YouTube videos to see how others using the gamma are doing it and trying to pick up some tips. I went to a park close to my house that has two HUGE play grounds for the kids. The ground is covered in rubber bark so it's not hard to dig, you just push the rubber around my detector kept beeping and I still never found nothing. So, it's a learning process for me. I'll figure it all out eventually. Thanks for the pointers, good things to know, HH

 

[Garbagebill]

I did turn my down my sensitivity from 80 to 60 and that helped a lot! Maybe that's part of it. Until I get use to it more. I actually found a rusted old bolt 8 inches down in my backyard. So I was pleased that it went off I dug and I actually found something without all the excess chirping constantly. It will take me time but I'll get it down

 

[locater]

Hey Bill, the constant chirping can be caused by several different things. First, make sure your detector is properly ground balanced. Everytime you start detecting, ground balance it, and rebalance it if ground conditions change, such as wood chips to dirt etc. Second, it could be that you have the sensitivity set too high, as you already mentioned. Adjust the sensitivity by starting at low or midrange and raising it to the point it starts to chatter of give false readings, then back it up to the point it runs smoothly. You want your sensitivity set as high as possible for maximum performance, but, not too high, as to give false readings and chatter. Third, there could possibly be a source of EMI ( electro magnetic interference) nearby. Such things as powerlines etc., that could interfere electronically with the machine, even a cell phone. It is most likely one of those causes, or a combination.

One possibility to check out at that park location is the "rubber bark". If it is made from recycled tires, they could have steel belting, it could sure cause your detector to go crazy. Don't get discouraged, it will all come together, just takes a little time. Good Luck.

 

[Garbagebill]

Locator: thanks for explaining it to me. I never even thought about the tires having the wire in it!! That's exactly how it was acting in the play ground! Like I was over a bed of wire!! I'm going to work on the sensitivity. And keep it as high as I can without it going nuts. Thanks for the suggestions. Hh

 

[Bart@Big Boys Hobbies]

Hey Bill, a 5" coil is usefull in trashy areas where you have a lot of junk mixed in with the good targets. The smaller coil allows you to get better separation between the targets that are close together. They are more sensative to smaller targets also, but give less depth.
The 11"DD coil gives much better depth and coverage. My first detector was a BH Platinum, which is nearly identical to the Gamma, with a few minor tweeks. It came with a stock 8" concentric coil, which I quickly changed to an 11" DD. The change was literally like opening the basement door, it gave much more depth.

The signal output pattern of the stock 8" concentric coil looks like a cone shape, wider at the top and narrowing as it goes down. Because of this pattern it is recommended that you overlap your coil sweeps by as much as 50% for effective coverage. The signal output of a DD coil is more a solid beem down the middle of the coil, with a more even pattern as it goes deeper. It requires very little coil overlap per sweep, which gives a DD coil much more effective coverage.

The general rule on coil size is, the larger the coil the more depth, but less sensitivity to smaller objects. Reverse that with smaller coils, less depth, more sensitive to smaller objects.

Hope this was helpful. Good Luck!

Great post!