White's TDI Coin Settings and Target Responses

[Steve Herschbach]

Hi,

The following is a “Power User Tip” from Steve Herschbach. It is not in the White’s Electronics TDI Owner’s Manual, and White’s Electronic's cannot be held responsible for any claims made in this post. I’m passing this along in good faith as information I have discovered, but which others have discovered first. I owe thanks to George, Reg, and of course Eric. But please understand my findings are preliminary, and can certainly be improved on by those of you willing to take on the challenge. It involves purposefully misadjusting certain controls to get results and I’m not even saying these are the best settings per se. I would encourage more experimentation to see what you can coax from the White’s TDI as I have not seen a detector so prone to experimentation for some time and yet with relatively few controls.

Well, I’m getting ready to head to my gold mine at Moore Creek on June 1st. Time to wrap up my in-town coin hunting experiment and prepare to find gold! So I want to post a summary of my coin settings and some observations on target responses for the new White’s Pulsescan TDI.

I highly recommend the use of a PI pinpointer with the White’s TDI. You need some serious pinpointing power. The Uniprobe units are very good, but you may need to switch the TDI off when employing the Uniprobe pinpointer if the TDI interferes with the Uniprobe. Coiltek makes a 1” probe with switch that can use the TDI itself as the pinpointer as the other option.

With the unit Off, set the TDI Gain at 12, Pulse Delay at 10uS, Ground Balance knob at 1.5, GEB switch On, Target Conductivity All, and then turn the unit Power On. Set for a faint Threshold. If you are getting any interference (uneven threshold, warbles, funny noises) slowly run the Frequency knob through its range seeking the quietest setting. Then flip the Target Conductivity switch to High. The threshold should go extremely smooth. If you get spikes or noises breaking through the normally rock solid threshold you may need to reduce the Gain. But usually at this point the threshold will be so smooth and solid you will find you can reduce it so low as to be barely heard.

Now try waving various steel items and coins over the coil and note the responses. You will see that most steel and iron, aluminum, and bottle caps will not signal. Beyond that, there are three basic responses. First, hold a coin 6-8 inches from the coil. Note the soft, sweet tone, woo, woo. Listen to it over and over, as this is your “deep coin” signal.

Now run a coin or larger steel item within 1 inch of the coil. You will get an overload signal, a strong baaaaawo, baaaaawo. This is the shallow item overload signal. If you are trying a steel or iron item, increase the distance from the coil. Note that at a certain distance it abruptly cuts off. Now try a coin and slowly increase the distance from the coil. It will gradually turn into that sweet coin tone.

OK, let’s go detecting. Listen for that sweet, deep coin sound. Those are the oldies and you main goal. In some hunted out parks this may be about the only signal you get as there are no shallow targets to generate the overload tone. Just go dig coins. Walk around each target and insure it gives a good, clean response from all angles. Be sure and use proper digging practices to leave the ground undamaged. Save our hobby!

In other places you will get lots of overload signals. If all you care about is deep coins, ignore them. If you want, however, just raise the coil while sweeping, and if the signal cuts off, skip it. If it fades to the deep coin tone, use your pinpointer and there should be a coin within an inch or two of the surface you can just pop out.

The Target Conductivity switch can be set too All to investigate questionable targets and to “size” targets. A pipe buried horizontally will have a high tone its entire length but a low tone at each end. When you walk around these in the High setting you will only hear the low tone and think it is a coin, but they tend to fade in one direction as you walk around them. If the target seems iffy, switch to All and see if you are picking up the end of an elongated iron or steel item. This false positive can occur well off the end of the pipe and so if you dig and nothing is there you may be off the end of a pipe or rebar. This is where a top notch pinpointer comes in handy.

The Pulse Delay seems to be most critical, and if you set in much higher than 10uS the ability to ignore iron is lost. But when it is working right the iron rejection is amazing. Try walking up to a garbage can or other large steel item. You will get no signal until you get close enough to overload the unit.

Not only does the unit ignore iron, but nearly all aluminum and bottle caps. The only ferrous target I found was a very rusted bottle opener buried vertically in the ground. If flat it is rejected but the TDI does pick it up if held vertically. I never did dig a bottle cap. I did get two aluminum screw tops that gave the shallow overload and that then sounded like shallow coin when the coil was raised. I got one older aluminum screw cap that was not deep or shallow so I checked it out. I also got positives on two copper wires, three chunks of broken heavy aluminum, an aluminum grommet, and a copper screw cap. I’ve attached a photo of my finds.

Oh yeah, I found 39 coins. That is 39 coins to 10 trash targets using a PI detector in a turf setting. That is a four to one ratio, and when hunting the deepest targets no worse than a VLF. Better yet, the targets that fooled me were not exactly “bad” targets by deep detecting standards. Three weeks ago I would have said this was impossible. I really did feel most of the junk was iffy but I wanted to check as I am learning. Coins sound oh so sweet and when I’m 100% sure it is a coin it almost always is.

What else to say? The GB control is in effect the discrimination control. It is all about setting the Pulse Delay, the GB control, and the all new Target Conductivity switch to get the best balance of depth and iron rejection. The iron rejection tends to be best at low GB settings, and in high mineral settings best depth is at high GB control settings. If you have no clue what I’m trying to say, you are not ready for the White’s Pulsescan TDI. In high mineral conditions you are trading max depth for max iron rejection. You have to set the unit for the best balance for your conditions. But if you get it right, hold on. This detector is amazing!

I have been able to run the Gain very high. I’m sure not everyone can based on where they are. So experiment, experiment, experiment! I have not spent any time to speak of trying the other side of the equation – the Target Conductivity switch set to low. Can you get rings and get rid of bobby pins on a beach?

And what about coils? Everything might change depending on the coil you use.

You tell me. Forget what you knew, and learn what you can. A detector for the Power User. Welcome to the new White’s Pulsescan PDI with thanks to Eric Foster.

Steve Herschbach

[Jim Hemmingway]

May 28, 2008

Darn good summary Steve.

It'll be interesting to hear your observations from out at the mine. Particularly with the higher mineralization, and your inclination to larger coils, to determine just how much effect these different size coils have on your GB settings. My hope is that your results will indicate an ability to at least eliminate some if not all "rusty" iron (as opposed to "heat treated" steel), even if that means going to a DD coil, or perhaps sticking with a smaller mono coil. Mind you, when searching for the lower conductives, generally broad based high tone signals indicating elongated targets could simply be ignored through user experience on that site.

Looking forward to hearing from you as time permits. And thanks for providing all this information.

Jim.

[Quix Ten]

Man, that sounds intriguing. Any ideas on how you would set up the detector if you were looking for coins/jewelry? It sounds as if your coin setup would eliminate a lot of gold items.

I'm really wanting to get a look at the manual for this beast. It sounds like a real jewel.

[Keppy]

Steve, I really appreciated the "Power User Tip"..Settings that you posted...... The TDI will be my next detector.........Thanks again....==Jim==

[extractor]

Hi Steve I just wanted to say Thanks for all your in put and tips on the TDI