Two-box unit for finding a cave

[Parangjim]

I have been doing research on various two-box units and they all claim effectiveness to depths up tp 2o feet for caches. My question is what would be the effective depth of a good two-box unit for locating a tunnel or cave? No, I can't afford a GPR unit just now. I need to do this with a two-box.
parangjim

[cptbil]

Parangjim:
Go the the White MD Site and check out the "808" !
It has "cave/cavern" mode.....
Works as above..!

[ColoradoMike]

Our Em units can find caves tunnel & the like up to a 100" deep. The surveys are very time consuming so you need to have a good idea where it is. The unit can give you a pretty accurate idea how deep wide ect. The walkabout may pick it up if it isn't to deep & the soil is right but wouldn't bank on it.

Good Luck

[ColoradoMike]

I agree on the 2 box. They aren't much use on caves or anything else in my opinion. I just gave one away the other day. A PI is a much better tool to go deep with. As far as caves, there is a company called Zong Eng. that will come out & do an amazing 3d scan. I have not seen it personally but someone I know in the Cabllos NM used it to map out a natural cave, it was over 80' tall. they could see the back filled tunnels & everything. So they said. I would like to see it for myself as I'm in the market for a real Good Imagining tool. They sell from $75K-100K but they will come to your site for $3500-$5,000 a day
? The EM-83 is a good tool but there is just so much material that it is not 100% accurate in.

Has anyone had any experience with any of the units from Accurate Locator's that does imaging? They are a whole lot cheaper.

[Tim Williams]

In the Arc-Geo logger field test the TM-808 was used. In one test you can see what a loose soil or a void would look like.
The field tes can be viewed here in PDF.

http://lrlman.com/Pages/Arc-Geo/Prod...0ARC-GEO_3.pdf

regards,

Tim

[Tim Williams]

Jeff you don't have to go to my site, just click the link and it will load in reader.
It's a PDF!

You are wrong about the 808 finding nothing unless you don't trust your own eyes.

Tim

[Real de Tayopa Tropical Tramp]

I could find nothing on your site. Just like the TM-808 finds nothing!
[/quote]
~~~~~
A)? sheesh Jeff, I have the Original 3-D, the White 808, and the Discovery model.? They work nicely for me, in fact they have kept beans in the pot.? ? ?What is your problem?

Perhaps you were not on an actual treasure location?

If there is no treasure there, or it has been recovered,? the? instrument cannot/should not? indicate one .

P.S.? As far as being the same as the Fisher, no way, they are VLF instruments with true ground cancelling abilities. The
Fisher is not, it is strictly a TR? machine, which while good, will drive you crazy with so called false readings.?

This is why it is good for mineral or vein hunting.


Till Eulenspeigle - Jose de La Mancha

[tagasilay]

Hi Realde,

I have had my discovery tf900 for 6yrs now. it looks and operates very similarly to the whites tm808, as long as i get the ground balancing right that will make the treshold purrr like a kitten, it will respond to targets within its range. The deepest i have got it to go in actual field conditions was 3ft, for a ww11 160lb bomb at a 45 degree angle, it gave a reasonable tight beep.( the target was large though) sometimes when im in full concentration, i could detect a beer can at between 1-2 ft, this sounds like a very slight increase of tone in the treshold. My question is, do you experience the same behavior from your machines, and what was your deepest recovery? My sensiditivy its always set in the normal, do you set ;yours to a higher level? hope you dont mind my asking.HH

God bless,

Jose

[rgecy]

tagasilay,

You should be getting much better depth than that. I can detect both those objects at depth with a metal detector fairly easily. Maybe Realde or some of the other guys who have a little more experience with 2 box detectors can help.

Good luck and let us know what happens.

Robert in SC

[Roadquest]

Fisher Two Box is the way to go.

[tagasilay]

tagasilay,

You should be getting much better depth than that.? I can detect both those objects at depth with a metal detector fairly easily.? Maybe Realde or some of the other guys who have a little more experience with 2 box detectors can help.

Good luck and let us know what happens.

Robert in SC

Hi Martin and Jeff

thanks for responding
Y0ur observation is correct about finding those objects with a regurlar detector, i know my sov would find them. Just wondering about the true potential of the twobox, if the garrett with depth multiplier can find a 4ftx4ft metal at 7ft, i guess the discovery and tm808 of whites should be able to do the same. Jeff, how does the 4x4 sound like at 7ft, slight hum or sharp tone? tnx

[tagasilay]

Hi to All,

Thanks for all the insights, all where helpful. hope to read more.

God bless,

Jose

[gflores71]

I have used a garrett with depth multiplier, then a Fisher gemini 3, then a whites tm-800 and now a whites tm 808

the whites tm 800 gave me better results in terms of depth, the best settings for it are the following:
manual ground balance and periodically press the balance button when the threshold starts to vary
sensitivity set to the higher limit of the NORMAL window
ground balance set to the lower end of the NORMAL window

and run the machine as low to the ground as possible

the tm 808 needs the sensitivity to the max and ground balance set lower than the NORMAL window to acomplish the same strength of reading

remember that once you find a target you can change to CAVE mode and see if the target is magnetic (ferrous) because the threshold will decrease and may go up if a large enough non magnetic metal is there

my tests have been performed using a 1 foot diameter copper frying pan buried at 3 1/2 feet deep for many years

from what I understand the TM 800 is now the TF-900, due to patent ownership that left whites with its owner, so the tm 808 is a new machine, however I have not tested the tf-900

so my choices in two box units rank : tm 800 (or tf-900 if same performance), then tm 808, then gemini 3 and last Garrett

again this is only my opinion from using these machines

[peg legged]

O.K. there seems to be a Great Debate about everything but no where do I see where there was anything really important or earth sharting recovered.
I have posted this several times so here it is again with a few details.
In 1928 gold was recovered from a Iron Chest in the Keys. This Chest now rest in Mckee's Treasure Museum on Plantation Key. The gold was transported up the Indian River. Somewhere along this line the person transporting this gold dumped it over board. It was NEVER recovered. It lays in feet of water with feet of mud and 8 feet of sand. There is a hard pan at 12 feet so it cannot go any deeper.
The Gold was in bars and estimated to weight around 1200 pounds total. Now my problem is finding/pinpointing the exact location and what type of detector will do the job. I know WHO, WHEN, and very close to where. In fact I have narrowed the area to about 25,000 sq, ft.
If anyone has any REAL answers please respond.
I love this forum.
Thanks
Peg Legged

[Real de Tayopa Tropical Tramp]

[=peg legged
It lays in feet of water with feet of mud and 8 feet of sand. There is a hard pan at 12 feet so it cannot go any deeper.
The Gold was in bars and estimated to weight around 1200 pounds total. If anyone has any REAL answers please respond.
I love this forum.
Thanks
Peg Legged
***************

A) HI Peg: Well I have experimented with my Garrett Sea Hunter and different coils with varying success. I modified an old Garret 2' BFO coil first, it actually gave me about 25 -30 % more range than the 12" coil, say 7 - 8' on a large object -air test.

I am now working on an old 36" Gardner single turn aluminum 1/4" tube coil. If It holds up, it might work for your depths of 12' underwater or used as a drop coil. I have 25 ft of cable permanently attached to the coils and use them as drop coils.

Drop coils are more efficent, since you can cover the area much more accurately and faster than diving. I genrally suspend a weight under the coil when operating, you can feel the difference when the weight hits bottom and so can lift the coil up until the weight is felt again - this allows a crude surface / depth control over the bottom.

Check into it.


Till Eulenspiegle de La Mancha
SWR, need your input and expertise.

[Rock]

Here is a set of plans that may interest you.

http://geotech.thunting.com/pages/me...seeker_300.pdf