Dissapointed in TDI. Or am I using it wrong?

[Quinc]

Bought a TDI and to practice using it I have been using a 1 pennyweight nugget. I can only bring the coil about 3 inches above the nugget and it stops picking it up! I also have the Jimmy Sierra coil and the same thing. The deepest thing I have found is a 1 inch nail at 5 inches deep. I am detecting around La - Porte Johnsville area (Nelson Creek) and there is a ton of blacksand trash etc. Is there a better coil I can buy for more depth and smaller gold or anything I can do to get more out of it?

Also, I found a spot that I just couldn't get it ground balanced so I dug to see what was going on, and this red shale looking rock was making it go crazy.

 

[arizonaames]

I think that one needs to go to the experts and read how to set it up for different conditions. Reg Sniff is the probably the best there is on the TDI outside of Eric Foster who designed the detector. You can reach them and get the information from them here:
http://z7.invisionfree.com/whitesgoldmaster/index.php?act=idx

The 1dwt nugget is a 1.6 gram nugget. You can easily detect a .3 gram nugget at 2 to 3 inches with the following settings: Gain at 12, GB on and GB set to 8 1/2 or balance for your ground conditions (you pump the coil up and down and adjust the GB to where it is the same going down as going up 2 to 6 inches off the ground), Freq midway or adjusted for conditions, threshold so that you can barely hear it with earphones, set the pulse at 10, conductivity set to low and you will hear a high tone. The 12 DF coil is best for gold. The elliptical Jimmy coil is also good. The TDI will work well in extreme ground conditions so you again are not setting up the ground balance correctly or you are having some EMF problems in that area. A PI is not a VLF machine and one has to relearn a PI machine. As you decrease your GB setting the depth will increase. But, for maximum depth turn the GB off if you can. Turning the GB off is not practical in very mineralized conditions and either is turning the GB down as the noise will take away from any depth gain. You really want a ground balanced detector and the TDI is not auto ground balanced. You have to do that as I previously described.

For coins, the setting are a lot different. You can discriminate out pulltabs, bottlecaps and nails but you will lose nickles and find all other coins. The settings for this is as follows: GB on, GB set to 2 1/2 to 4 (usually at 3 1/2), pulse at 10, gain at a stable place at 10 to 12, freq as required, set conductivit switch to high so that you will hear a low tone on target. Threshold to barely audible with earphones.

This should get you started in the right direction. A PI is not a VLF detector and you will have to throw out your knowledge of a VLF detector and start anew. Although, ground balancing is the same for any VLF detector that does not have auto ground balancing.

 

[Quinc]

Great info, thank you! I will keep playing with her and hopefully post back in a nice find.

 

[Jim Hemmingway]

Hi Quinc....ArizonaAmes has given you good solid advice. When seeking help, it would be a good idea for you to let us know how you were operating your machine. For example... include your gain and ground balance settings, and did you have the tone mode switch set to "All", "high" or "low" conductives. That information would make it easy for us to spot any obvious problem.

The other thing to consider is your nugget. Some nuggets don't respond well to PI units because of physical factors such as structure or shape....sometimes these are referred to as nugget "character". I've got a one gram nugget that will beep out to 7 inches and other similar size "character" nuggets that don't respond beyond a few inches at most. Be a good idea to either describe it or better yet to add a good photo of it. Photos are easy to do on this forum and there is a special sub-forum section put aside for members to practice posting photos.

Jim.

 

[arizonaames]

Jim is quite right about the size, shape, weight, and composition of the target including a nugget. I have a few nuggets that are .2 to .3 nuggets that will not be detectable with the TDI. I have one .3 nugget with a lot of surface that I can detect 2 -3 inches from a 12 DF coil. I have previosly complained about the lack of sensitivity and depth of the TDI in comparison to a ML4000 or ML5000. However, the TDI is easier to use, lighter to carry (you can put the box on your belt or chest carry it like I do), you can discriminate out some iron targets, and it is quieter in very bad ground.

I have, however, noticed that there is no standardization with a TDI from the factory. Each detector is a bit different and ergo is different in setting up the controls to some extent. One has to tweek it according to your particular detector. Jim Hemmingway is a very knowledgeable and great source to ask about the TDI and will give you help with a practical jargon.

 

[arizonaames]

I set up a test garden for the TDI and the results were dissapointing. The greatest depth with the GB on and balanced to the ground conditions both in High and Low conductor mode was as follows. In All mode, there was too much chatter with targets (small pieces of foil or trash) close together. With the GB set at ground balance.....8....and the conductor mode set to high I could not discriminate out nails, bottle caps, or pulltabs until I brought the GB down to 3. With the GB at 3 I could not detect any of the targets including a penny, dime, and quarter at 6 inches. In Low conductor mode, I was able to somewhat discriminate out some iron to find nickles and small gold. In high conductor mode and GB at 8 I was able to detect a dime at 6 inches with a very faint whisper but not at 7 inches. I was able to detect a quarter at 7 inches but not at 9 inches. I was able to detect a penny at 6 inches but not at 7 inches. The settings varied a bit for best results but the best results with the GB on was GB set at 8 for my ground conditions, gain on 12, Freq centered, earphones were best with a very faint tone. The depths were measured depths with a ruler prior to being buried. I did get a good hit on a very tiny silver ring .925 at 6 inches which was better than expected where a dime did not register at all at 7 inches.

With the GB set to off one gets just a high tone so I set it to All mode. Here, I was able to detect all targets including a quarter slightly at 9 inches. In very mineralized soils one cannot run this detector with the GB off. Seems that these detectors are set up differently and the results on each detector can be significantly different from detector to detector. The lack of both depth and sensitivity were the same that I experienced nugget shooting with this detector in NV.

 

[Quinc]

I set up a test garden for the TDI and the results were dissapointing. The greatest depth with the GB on and balanced to the ground conditions both in High and Low conductor mode was as follows. In All mode, there was too much chatter with targets (small pieces of foil or trash) close together. With the GB set at ground balance.....8....and the conductor mode set to high I could not discriminate out nails, bottle caps, or pulltabs until I brought the GB down to 3. With the GB at 3 I could not detect any of the targets including a penny, dime, and quarter at 6 inches. In Low conductor mode, I was able to somewhat discriminate out some iron to find nickles and small gold. In high conductor mode and GB at 8 I was able to detect a dime at 6 inches with a very faint whisper but not at 7 inches. I was able to detect a quarter at 7 inches but not at 9 inches. I was able to detect a penny at 6 inches but not at 7 inches. The settings varied a bit for best results but the best results with the GB on was GB set at 8 for my ground conditions, gain on 12, Freq centered, earphones were best with a very faint tone. The depths were measured depths with a ruler prior to being buried. I did get a good hit on a very tiny silver ring .925 at 6 inches which was better than expected where a dime did not register at all at 7 inches.

With the GB set to off one gets just a high tone so I set it to All mode. Here, I was able to detect all targets including a quarter slightly at 9 inches. In very mineralized soils one cannot run this detector with the GB off. Seems that these detectors are set up differently and the results on each detector can be significantly different from detector to detector. The lack of both depth and sensitivity were the same that I experienced nugget shooting with this detector in NV.

Are you using the stock coil? I'm hoping that upgrading to a Razor back it will get better.

 

[arizonaames]

A mono coil will gain you and inch or two in depth but you will lose some sensitivity for small gold. The DF coil was designed by Eric Foster for finding small gold nuggets.

 

[Quinc]

Quick update, my dad took the TDI out last weekend with the Razorback 5x8 coil and in the first 5 minutes of detecting an old tailings pile found his first piece weighing in at .6 pennyweight! He was also using the Sennheiser RS 160 wireless headphones and loves them.

Anyone want to buy my old Jimmy coil? Sell it to you cheap!

 

[dbsmokey]

Quick update, my dad took the TDI out last weekend with the Razorback 5x8 coil and in the first 5 minutes of detecting an old tailings pile found his first piece weighing in at .6 pennyweight! He was also using the Sennheiser RS 160 wireless headphones and loves them.

Anyone want to buy my old Jimmy coil? Sell it to you cheap!

How cheap? I might be interested!

 

[Quinc]

Quick update, my dad took the TDI out last weekend with the Razorback 5x8 coil and in the first 5 minutes of detecting an old tailings pile found his first piece weighing in at .6 pennyweight! He was also using the Sennheiser RS 160 wireless headphones and loves them.

Anyone want to buy my old Jimmy coil? Sell it to you cheap!

How cheap? I might be interested!

Real cheap! I will send you a pm