My new TDI

[arizonaames]

I had my first chance to try out my new TDI today. The weather was warm as toast, 34 degrees. I first did some test checks with my MXT and wrote the VDI #s on a slip of paper for each item found in the ground with the MXT. Most were pulltabs and a few were bottlecaps. I also found 2 pennies. I marked each with the VDI #s.

Then, I went over the finds with the TDI and tried different settings. I first used the settings that was recommended by Steve H and others. I could null out the pulltabs and nickles very well but still was hitting on a steel philips head for an electric drill and bottle caps. Still playing around, I found that by increasing the pulse from 10 to 25 that I was able to null out the philips steelhead completely. The bottle caps still came in probably because the VDI on bottlecaps is between 46 and 70 (almost the same as a penny). I was still picking up the dime, quarter, and penny when in high and the pulltab and nickle (canceling out the others) in low. It seemed to work best with the frequency very low and the ground between 1.5 and 2.5. Threshold was minimum and gain was all the way up to 12. The ground was still frozen solid beneath the snow but I was able to confirm one penny over a septic tank where the snow and ground had melted.

I was impressed that the depth was greater than my MXT. I also used both (all) for high and low and it was comparable to one setting. I also found that the depth was greater with the GB off but then you lost discrimination. Am I on the right track here?

One negative thing that I noticed was that the sweep speed was considerably slower than my MXT either in 10us or 25us. The recovery on the MXT was a lot better and it made no difference whether I swept fast or slow with the MXT. This was my first time using a PI unit.

 

[arizonaames]

It finally got warm enough to go over a piece of ground that I got a hit on with the TDI the other day. It was a solid hit and the MXT read a 74 VDI#. I went back out with the MXT and, with the DX-1 probe, found a bottle cap. Like I said the other day, if one were to discriminate out bottle caps, one would lose dimes, pennies, quarters, and most silver. By nulling out iron and pulltabs, one loses nickles and small gold but will pick up silver targets and pennies. The TDI is primarily a gold nugget hunting machine for bad ground conditions. It is also used where there is bad ground conditions where there is red clay in Georgia and other southern states for relic hunting. It is in bad ground conditions that the TDI (PI) detector will outshine a VLF detector because it will hit on items deeper where a VLF detector will not work or will not work well. However, for small nuggets in somewhat decent ground (pickers in the 1/2 grain to 3 grain range), a VLF gold machine will outshine a PI detector. Many posts that I have seen wish to be more politically correct than to tell it like it is. Remember, the TDI was not meant to be a coin or relic machine but in bad ground conditions, it will give you options that a VLF detector will not and yet you can still have some discrimination.

 

[Cupajo]

As some one completely un-familiar with the TDI I am grateful for your information.

I,like most hunters, am interested in machines that can maximize my results for time invested!

Please keep us posted with any information you wish to share!

Gratefully,

CJ

 

[arizonaames]

I was able to try out the TDI again today with fixed targets. The temperature was a balmy 33 F.

With these settings, I was able to cancel out a dime, quarter, and a penny. I was also able to tell the difference between a steel philips insert (iron) and a nickle as well as a pulltab (gold nuggets VDIs). I was amazed that I could tell the difference between the philips insert and the pulltab and nickle (20 VDIs) since the iron would be a neg to 0 VDI# (close to the 20 VDIs). The philips would give a hollow lower high pitched sound vs the straight high pictch sound of the pulltab and nickle. Here are my settings. GBn, GB:1 1/2, Pulse Delay:25, Gain:6, Target cond:low, Freq: midrange, Threshold to a slight hum. In my mild ground, I beleive that I could have turned the gain up to 12 without much of a difference and it would have given me greater depth. It was very quiet with no chatter or emf noise.

 

[MikeInSF]

Try setting your GB to 9 and pulse delay to 10. Now the iron (nails etc) should give a low tone and the pull tab, nickel, many gold rings should give a high tone (with target cond switch set to all). If you switch the target cond. to LOW, then you should only hear the high tone for the pull tab and nickel and nothing for the iron (also nothing for high conductive copper, silver, and clad coins). Small iron like bobby pins, fish hooks, etc will still come through (problematic for beach hunting). Also, not all gold rings will respond as a low conductor under these settings.

If you're after coins, try GB at 4 or 5 and pulse delay at 10 and target cond switch to HIGH. Most low conductors (pull tabs, nickels, etc.) and most iron (nails) will not give a response (since you have the target cond switch set to HIGH) or won't give a clean response, but copper, silver, clad coins will give a clean low tone response.

Hope this helps.
HH
Mike

 

[arizonaames]

If you try my second settings, the fish hooks and bobby pins will sound off differently than a pull tab and nickle. You will hear a LOWER high tone for them so that you will not have to dig them. I started off using the settings that you recommend but I wanted to cancel out all iron that was the same size or smaller than my coins and pull tab. You can do just that. This is what impressed me with the TDI. Yes, you can, to some degree, cancel out small iron objects or at least tell the difference between them and other targets. You can control the discrimination by also using the Pulse Delay as well as the Ground Balance. If you were looking for small gold nuggets, you probably would be better off using 10us instead of 25us and then you would have to dig small shards of iron. This is what makes me wonder that if we can discriminate, to some extent different metals; ie: pull tabs, nickles, iron, silver coins and pennies, then why would it not be possible to assign VDI #s or other signs to a display in the future?