The Use of EM in Treasure Hunting !

Jason_05

Jr. Member
Sep 13, 2005
22
3
Decapolis
Detector(s) used
Garrett GTI 2500
Hello ,

What is the best EM instruments that can be used for T.H ?

As i know : VLF , PI , 2-Box detectors have a limited range of depth ! and will not be able to detect any kind of treasure in a depth of 6m - 10 m ?


May be the answer will be using EM devices ! i don`t Know .... !

I have found many companies with great EM models, like :


-The EM34-3 by: Geonics .

-The GEM-2 by: Geophex .

-The Profiler EMP-400 by: GSSI.

-EM 34 by: Geomodel.


What is the best EM instruments ?



Best Regrads
 

That's really a good question!

The answer depends on what you are looking for. As usual, the target has to be sufficiently large and have "contrast" compared to the surrounding ground.

EM systems as you can see from the research you have done, come in many different sizes. The general distinction is "frequency domain" and "time domain".

Frequency domain EM systems are continuous output T-R units that vary in frequency and power output. They may be fixed or variable in power and frequency but are usually fixed. These can measure conductivity and susceptibility depending on the type whether they measure the in-phase or out of phase signal at the receiving coil. The depth of penetration is approximately equal to the coil spacing. Higher frequency systems do not penetrate as deep. It has to do with a property called skin effect and is related to conductivity. Since electromagnetic waves diminish as they penetrate into the earth, the secondary returning waves diminish as they return to the receiver. More distant targets must be much larger in order to generate a detectable signal change.

Time domain EM systems fall into the realm of Pulse Induction units. Pulse Induction is based on the concept of pulsing a loop (coil) with sufficient current to cause a momentary electromagnetic wave to enter the ground. That momentary wave (pulse) propagates downward and if a metal/mineral target is intersected, it generates a secondary electromagnetic waveform that returns to a receiver coil. The receiver coil converts the EM return into a voltage. The voltage is sampled at time windows beginning at the instant the transmitter pulse ends until no signal remains or a predetermined time. Interpretation of time domain can include a good estimation of depth of a given target.

The best system depends on the application. EM systems in general are good for detecting conductive targets that have good conductivity contrast to the surrounding earth. In areas having "hot rocks" PI systems will find all of the hot rocks. EM systems are used in a broad range of applications. Care should be used in selecting the "best" tool for your application!

Lots of luck!!!

Geowizard
 

Jason_05 said:
Hello ,

What is the best EM instruments that can be used for T.H ?

As i know : VLF , PI , 2-Box detectors have a limited range of depth ! and will not be able to detect any kind of treasure in a depth of 6m - 10 m ?


May be the answer will be using EM devices ! i don`t Know .... !

I have found many companies with great EM models, like :


-The EM34-3 by: Geonics .

-The GEM-2 by: Geophex .

-The Profiler EMP-400 by: GSSI.

-EM 34 by: Geomodel.


What is the best EM instruments ?



Best Regrads

Hi Jason,
From what I heard from real users, the EMP-400 Profiler from GSSI is a very good FDEM system.
However, depths of 6 to 10 m is VERY AMBITIOUS for ANY type of instrument except if the 'treasure' is BIG!!!

Willy
 

Geowizard,

what is your opinion about EMFAD UG PRO? to which category of EM does this unit belong? It is said that EMFAD can detect up to 12 meters depth.
 

I would go with the Profiler EMP-400 by GSSI. A friend of mine tested this unit down to about 20ft with good results.

Tim
 

I have a hard time believing 20 feet with the profiler. Based on its geometry and operating frequencies, getting 10 feet would be a lot. I used one in February and was pleased with it but it couldn't detect an 8 inch diameter steel pipe below 10 feet. I can find the image of the pipes that we buried and that Profiler data that we collected over them if someone wants to see it.
 

Well The profiler is rated to 16 ft and Dan tested it over a highway culvert that was at lease 18 to 20ft. I saw the plots he was very pleased and he should know. If you want to talk to him his number is in the back of the field test report he did on my Arc-Geo logger. This is what he does for a living.

Tim
 

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The best way to choose which equipment works best for you is to test them on known targets. I personally use the OKM and have used the EMFAD. Results were similar with both units but I found the weight of the 2003 was the winner in my book. Especially when you have to carry it all day.

Though I have never used the GSSI, I know of others who rave about the software, which OKM needs some improvement in theirs.
 

cassbiz where do you live? I have a friend that purchased a emfad a few years ago and still cannot get it to work. Then found out that the signal needed for the emfad is not in the USA! Why did emfad sell the unit to him if he could not use it? He has been trying to get emfad to replace the unit with a updated one. They will not. He would have to by a new one and they will try to sell his old on. What kind of people is this? Last I heard he sent the unit to them and that was over 2 months ago and they still have it.

Tim
 

The EMFAD works here. What does he mean the signal isn't here. EMFAD stands for "Electro Magnetic Field Area Detection". If you have a magnetic compass and it works, then the EMFAD will work.

I live in Florida about 45 minutes North of West Palm Beach.

I sold and was tech support for OKM products for years, so being somewhat well informed, I also know of the competition like the EMFAD. The unit works in most soil conditions, although there are some soil conditions which attenuate the EM signal. These soil conditions affect ALL detectors regardless of the technology.

Please have your friend send me a PM and I will make contact with him. Though I cannot remember all of the specifics right off the top of my head, I will gladly try to assist him so that he doesn't end up with a very expensive dust collector.
 

This is a question for all treasure hunters: If you know about a deep treasure( in land ) wich system do you choose EM or resistivity with imagining software?.
 

I use both. I like resistivity, the only downfall is how many times you have to re-position the ground probes. Once I find a sight with the EM, then I use the ground resistivity.

Both are good.
 

jesus said:
Why not viceversa ?

Because of speed. With the EM machine I can cover an area the size of a football field which will be 2ft on center in about an hour. If a hole was dug then I will be able to return to that point and use the ground resistivity. Doing it the other way around, you will have to move your probes 100+ times and in some of the places I treasure hunt in, the soil is very hard.

The trick with the EM machine is to look for the hole or fracture zone.
 

Thanks cassbiz, always is good to hear somebody with field experience, somebody who uses different devices, this is realy good because some ocations we are victms of fraud with some traesure devices that in teory say one thing but in field are another, we can see this in many posts , many people question wich device is good and they recive many different claims from people with a little or non experience in field, this is realy inportant in cache hunting were we need more tah one device and if we think in price is good to hear somebody with experience in field with that device. Thanks.
 

jesus said:
Thanks cassbiz, always is good to hear somebody with field experience, somebody who uses different devices, this is realy good because some ocations we are victms of fraud with some traesure devices that in teory say one thing but in field are another, we can see this in many posts , many people question wich device is good and they recive many different claims from people with a little or non experience in field, this is realy inportant in cache hunting were we need more tah one device and if we think in price is good to hear somebody with experience in field with that device. Thanks.

As a treasure hunter you are just as familiar that weight is a major factor. I like light devices, though I still have several very heavy ones that I dread to take out, but use them because there is no one perfect device. In the readily available EM, I am partial to the OKM Rover C / C II because of its versatility, functionality and weight. Also they have a proven track record from real users not just manufacturers.

Good Hunting!
 

Beste allemaal.
Ik ben op zoek naar software om Emfad-gegevens te kunnen analyseren, visualiseren.
kun je me daarbij helpen.
Bedankt
 

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