Mark Gillespie

Amazing and very clear answer Reg. Thanks so much. I'm convinced I need a mono coil in place of the stock 12". Had something very interesting happen or yet discovered about the TDI that I might share when I prove it to be fact. Well Reg most likely already knows.

This is an old school yard. The schools in my area burn coal for heat. They take the waste from the furnace and spread in the school yard. The majority of this bi-product easily attracts to a magnet. All this happened many years ago, now the EPA requires waste be taken to the land fill.

Posted the following on a particular site and almost immediately picked up ridicule for adjusting the TDI in the manner stated. I'm a very open person and can take constructive criticism if need be. After several hours hunting with the TDI SL I finally found the perfect settings for this particular site. This place is littered with the waste bi-product of burnt coal over many years. Much of the waste is small in size, ranging from BB to marble size and the smaller pieces easily attract to a magnet. In addition to that, the area is littered with nails ranging from 1 to 4" in length and some up to 4" deep. These nails, especially the larger ones give a good audio, especially with a ground balance of 8-9. After a suggestion from Reg, I began adjusting the GB to 4-5 and if the signal became inconsistent then the target was most like a nail. After a lengthy amount of hunting I decided to run the machine at gain max, pulse 10 and GB of exactly 5. Surprisingly the false signals all but stopped and I started finding old copper pennies some being wheat pennies in an area where I had gridded off and cleaned out of all good targets. Amazingly, I still can't believe I had missed that many targets with my other machines. Now my next plan is to locate, what I believe to be good non-ferrous targets with the SL and mark each location. Then use my regular VLF machine and see if I can detect each target and note the audio responses given. Many things to consider in this journey, very excited to say the least. Well it seems some people on other sites think it is a sin to adjust the TDI the way I did in the following statement. I want to add one thing; the ground I hunt is very unique. All I'm stating below is what I observed and found to be true at this site on this day. I'm very well aware the best settings would be GB 8 and pulse 10, but the ground does not allow the best settings to be used to produce what I'm looking for. Coins mixed in with heavy coal waste made of iron, BB size to marble size to be exact. Well, went back to the same site where I posted, "perfect settings for this site" and hunted a small area not more that 60' from the prior hunt. Used the same settings "GB 5, pulse 10 and gain max" and off I went. After a short while I noticed a lot of clipped or inconsistent audio reports. Decided at that point to reduce gain to 7 and continued. Hunted a few more feet, still clipped audio, strange, so I stopped to analyze the area a little more closely, sweep in one direction and get a some what good audio, but the return sweep was either silent or chatter. Suspecting something was the cause I stopped and increased the pulse delay up a tad, nothing changed. Continued to increase the pulse until I reached 17 and suddenly the audio came through as a loud, almost overload low tone. Thinking it might be a nail; I dug and out came a copper penny at less than 4" deep. Now to say the least, I was excited and puzzled. Decided to start over where I started hunting and experiment using a pulse rate of 17. A few moments later came the same type of loud low tone. Thinking there is no way I missed that one my first pass I changed the pulse to 10 and the signal all but disappeared. Increased the pulse to 20 this time and spent over 5 minutes rotating around this target checking from every possible angle to see what might be causing the anomaly, switched the conductivity switch to all and still a consistent low tone with nothing else mixed in. Now one must keep in mind I'm using the stock 12" and at times it is very difficult to exactly pinpoint where the target actually is. Changed the pulse to 10 and the low tone practically disappeared. Now I was wishing I had brought my Deus to recheck some of these inconsistent signals, maybe next time. Well anyway I dug a nice plug and out came a wheat penny at less than 5" deep. I was very excited to recover something from an area that quit producing years ago. Continued hunting with settings of pulse 20, GB 5 and gain at 7, and found many more coins dated in the early 60's all within a 3' path some 60' long. Already planning what I'll do my next hunt. What I learned from this hunt: Regardless of what some may say, don't assume you have the best settings for any site especially the sites where coal waste has been discarded for many years. I'm suspecting the partial or complete cause of the anomalies is the small BB size waste particles from the coal fired furnaces that will easily attract to a magnet. In fact dropping a strong magnet into the same hole where a coin was revealed exactly that. I'm relativity sure I need a mono coil, but undecided as to what I'll get. More reports to come.

Whites TDI SL Went to an old school where the coal cinder waste has been dumped for years and hunted for 1 ½ hours. This area has been grid hunted for years and I was sure there were no goodies left to be found. Well wrong again. GB to a little over 8, pulse 10, gain 10 and off I went; very first signal was a wheat penny at 4-5 inches and perfectly vertical. You can see the scratch I made with my shovel. Wow, was I off on my pin pointing skills. Couldn’t believe how I could have missed that one because it gave a very good, consistent audio response from every direction. One thing I noticed, it didn’t give a double beep like a VLF machine would on a vertical coin. Thought I had the sound nailed down, but was I wrong. Started digging nails, three to be exact, all sounded fairly good but I could tell there was something wrong, but I’m learning, so I dug anything that sounded remotely good. A few minutes later, not more than 10’ from the penny, another signal that sounded different, not sure what sounded different, still learning. Wow, a silver dime and not quite 5” deep. Now I am wondering how I could have missed that one, not a clue yet. Well anyway, the next two targets were nails, then another perfectly vertical copper penny. Had a very good hunt, for an area that basically dried up over a year ago. Wonder what I'll find once I have a little time on this machine?

Well a good while back I finally decided and purchased a Whites TDI SL. As always, each new machine has to pass through my test garden. Did some detailed work in my test garden yesterday using the TDI Sl. First results are very promising. Settings were, pulse delay 10, ground balance 7 ½, gain max threshold just audible. I have a copper rivet buried at 7” about the size of the end of a pencil eraser a 6 ½” quarter, dime, nickel and penny along with each at 4 ½” deep in a different part of the test bed. In addition to these I purposely left nails where they were when I planted the garden over 7 years ago. Please keep in mind these were the depths when I put them in the ground, so the exact depth is not known after 7 years. Starting off in high conductor mode each (except the nickels) gave a very good, smooth audio in every direction except the nails which gave a completely different sound, very much different. Keep in mind I’m still in a steep learning curve, by no means close to experienced but having a fantastic time on my journey. After listening to the differences between the coins and nails I reduced the gain to about half and listen to each target again. I continued reducing the gain little by little until the deep coins and rivet ceased giving a audio response and that was about gain 3 ½. Raising the gain back to 4 and the coins gave a very faint, low volume tone. Wanting to play a little I raised the pulse rate, re-ground balanced and checked each target with a gain setting of 6. The biggest difference came when the pulse rate was set above 20. The coins still gave a good audio, but the rivet, which is very small compared to the coins, became difficult to hear, very statically, extremely low in volume. All in all I had a very enjoyable evening, very educational. Mark Gillespie

Thanks for all the input guys

Any procedures to determine if a coil is bad?

I meant the Detector Pro PI machines that have the electronics in the head phones.

What about the detector pro PI machines?

The CTX was used by my hunting buddy. He has about a year experience and has been beating my butt with finds. He tried every possible settings. Finally he opened the screen completely and ran with a manual sensitivity of 28 and could only get tick on a 4" dime. I know it is hard to believe, but we both know a PI has to be the next machine for one of us.

Thanks so much for the added information. I find it hard to believe this area doesn't hold a lot of goodies, just out or reach. I have pictures of many people playing ball and huge crowds of people setting and laying around watching the games. I could be very wrong about the potential, but it just makes sense to me. Thanks again. If they ever dozed the top, just a few inches I'd know for sure.

Editors note: Mark contacted me regarding the use of a PI, specifically the White's TDI, to try and get better performance on coins at a difficult location. I asked him to post here to get the ball rolling on the subject - Steve H The reason I'm asking these questions is because where I live all the old schools used coal for their heat source. After burning the coal the waste was spread out over acres of land to get rid of it. Most is the size of a bb up to maybe a small marble. It is some sort of iron makeup because it attracts to a magnet fairly easily. And as you well know a regular VLF machine is rendered about useless with the exception of very shallow targets. Over the past 7 years I have owned or borrowed each of the following machines and none can get any depth over 4" in these areas. The following is a list of the machines. Tesoro Vaquero, Tejon, Lobo Supertrac, Garrett A250, Teknetics Eurotek Pro, Fisher Gold Bug Pro, F75 and the LTD version, Whites XLT, DFX, V3i, Minelab Explorer SE, Etrac and CTX 3030. Please keep in mind, not all the machines were mine. Some were loaned to me just to try in this bad coal cinder ground. One interesting note about the Minelabs, when auto sensitivity is used the machine will throttle down to 8 or lower in these areas. Now you might be wondering why I'm so interested in this one particular area well it is because it was one a huge group of ball fields used back in the 40's right on up to the 70's. I have pictures of actual ball players and at times there were hundreds of people watching games. Now that said, there should be many silver coins at this location, but none have been found and I can only guess it is the ground. Because over the years we have buried coins at 4" deep that none of the machines mentioned earlier can detect and 4" is not deep for any of these machine. So my assumption is that the material robs the transmit signals from the machines to the point depth can not be achieved. I have talked to Carl at Whites and Dave at 1st Texas about these extreme harsh locations and actually sent them each a 4 pound box of this material to test. Dave suggested ground balancing to the material and using the motion all metal mode to hunt. This provided some positive results, but only to about 5" in depth. On the other hand Carl was working on a PI prototype at the time and could only provide his comment, which was, no VLF would be able to perform at these locations. After reading many of your post and watching your videos I decided to contact you for additional information. I sent Carl another message after reading about your postings on the Whites TDI and here is his reply. Re: dirt Quote Originally Posted by markg Carl, a guy that hunted the digging in Virginia swears that the Whites TDI will punch through this kind of dirt. I know you can agree or not on this subject. But the cost of buying one to try would be a gamble. What do you think? Quote Originally Posted by Carl-NC just tested your cinder soil with a TDI... it's actually pretty mild compared to my Australian soil. The Oz soil is strong and has a very tight ground balance setting, whereas the cinder soil is weaker and has a broader GB range. So I think the TDI would handle this stuff easily. Regards, Carl I guess I really would like someone close to where I live visit and try a pulse machine. That way I would know. I can provide an open invitation to hunt about any evening.