Earth Resistivity (long request}

[Hussain Dada]

Hi All. Great site. I'm an utter newbie at treasure hunting (although not at electronics) and only became interested after a friend requested me to help him decide on what equipment to purchase. He decided to get an Accumeter, but I fortuitously stumbled on to this site before he made his purchase. From previous posts, I gather that the project published in EPE magazine is more sophisticated(and much cheaper to build) but runs at a much lower power output. Is this so? How does the lower power affect its performance? Is it possible to raise the output?
Have any of you gentlefolk read the articles and, if so, what are your opinions?
I am not neccesarily bent upon Earth Resitivity devices and would certainly consider any other devices that you may recommend.
The gentleman has fixed a ceiling price of $7000 and intends to look for buried caches and relics which he suspects lie about 20 to 40 feet deep. This is in the Tribal areas in Pakistan, barren hilly land.
I would be extremely grateful for your help, opinions, advice.
Best Regards, Hussain

[Carl]

Re: Earth Resistivity (long request}

The Accumeter & other "GPLs" are simple 2-probe meters. They basically "work", if you're very careful. You can build one of these easily for $50 or so, and save $5000.

The EPE resistivity meter is a true 4-probe meter, which generally gives better results, and also has data logging & software, which makes resistivity measurements MUCH easier.

The EPE meter has active electronics, including a sense differential amplifier. The GPLs are all-passive, the probes directly drive the analog meter, so more power is needed to make them work. This is analogous to building a metal detector in which the receive coil directly drives a meter, with no electronics in between.

- Carl

[Hussain Dada]

Re: Earth Resistivity (long request}

Thanks for your reply Carl. What would be your detector of choice in a situation such as this?
Much obliged for your help.
Best Regards, Hussain

[Carl]

Re: Earth Resistivity (long request}

Don't know, as I don't know enough about the circumstances. 20-40 feet is awfully deep, people don't usually bury things that deep. And, it would depend heavily on the type & size of the targets, and what else might be in the area. Plus the terrain. Besides ERM, there is GPR, IR imaging, and large-coil pulse induction. Probably others.

- Carl

[Hussain Dada]

Re: Earth Resistivity (long request}

Thanks Carl. Sorry for the delay in replying. I've been offline.
Best Regards, Hussain

[Tony Deknes]

Re: Earth Resistivity (long request}

Hello Hussain,

There is an excellent section on ERMs in "Seeing Beneath the Soil" by Anthony Clark. It also covers other technologies that may be applicable to your situation. While somewhat dated, the theories have not changed as dramatically as technology. I recommend that you read it - if you can acquire a copy.

My personal opinion is that an ERM could be very helpful in locating an extremely anomolous object of about a cubic meter size in homogeneous soil 30 to 40 feet deep. However a very precise (and tedious) measurement and recording regimen and excellent equipment and measurement interpretation software would be required. And then there's the fact that the soil isn't necessarily homogeneous... If you're looking for caves or shafts, though, it may not be so difficult with an ERM. It would take a long day to accurately probe/measure an area the size of an American Football field - approximately 50 meters by 100 meters with the resolution you would require. And I don't know of any readily available (cheap) software capable of that resolution. Is it the right tool? I don't know.

There are no magic wands - and that's a good thing! If there were such a thing, there wouldn't be much left in the ground for the rest of us to look for.

[Hussain Dada]

Re: Earth Resistivity (long request}

Hello Tony. Thank you for your reply. My apologies for not having responded for such a length of time. I have been up in the area of concern for the past couple of months exploring and noting areas of interest. Very interesting indeed. There are ruins in practically every valley, some along the ridges and some down on the valley floor. There are ruins at every spring where it emerges from the hillside. There are several caves that have obviously been worked on. And there are mounds thirty odd feet high. Some of these sites have been disturbed by villagers, some have been excavated using dynamite!!! But none have been systematically explored and excavated. Just searching manually, I was lucky enough to find a few coins, some from Seleucid Dynasties and some from later than that. Largely a mixture of copper and silver although villagers say gold coins are also occasionaly found. What really had me going is the fact that bronze and stone sculptures are also found in the area.
I will most certainly try to find the book you mention. I am much obliged for your reply and seeing how you posted on Christmas day, hope you had a good one.
Best Regards, Hussain