auminesweeper

Sorry Mark I can't because I sold both of my TDI's just before I went in to hospital due to the surgery and recovery etc I was told that I would not be detecting any more but as I found out that is not the case, which means buying more in the future, lol.

Jim, Mine was built in 2013 as well, but none the less mine did not show any depth advantage with the GB switched Off, all I noticed was that smoothing effect that the TDI pro does with the GB off my SL did it when the GB was On which means it was trying to balance out the target. Well we have 3 for 3 that all show zero depth increase with the GB off, which is making me start to doubt the many posts I have read claiming that there is a depth increase with the GB Off, Yes there is with the TDI Pro but Not the SL.

Well Jim mine would not see an 0.17 gram bit which is equal to just over 3 Grains with the 12" DF coil or the 7.5 DF coil not even with it sitting on the coil, regardless of the battery voltage.

Yep so was mine a 2013 Jim, I don't know how digger bob got is to see his tiny test pieces in that video but mine wouldn't see them, It ran as smooth as silk even with a thunder storm going on right about the house Nothing phased my TDI SL, all it took was a minute tweak of the Tune knob and it was good as gold, My 3500 didn't like storms 100 to 200 miles away but the SL has the best threshold ever put in a detector.

Well Air testing a PI although it's fun and informative, Many believe that PI's actually do better when a target is in the ground because when a target is in the ground a PI sort of electrifies the Ground/Target combo and it measures the response time hence the name TDI and depending on the moisture/ ground makeup can add to the depth although a PI does not like soaked ground it does do well is the ground is slightly damp, Where as a VLF is good in very damp ground but not soaking and they start to loose depth in very dry ground,. The depth of a machine can only be seen on genuine target recovery, I had a 3500 that air tested quite well yet in mild ground in 2 spots at the same location I found a VLF seemed to be just as deep. This is not a dig at anyone because I made this very mistake. "But". The trouble is many folks see a PI as a magic stick like some Super deep all seeing eye but the truth is they are not, All they do is give normal good detection depths in difficult ground conditions where a VLF Suffers, In normal conditions a Sovereign GT with a 10" coil and a GP3500 with an 11" DD have fairly even depths, and in the same soils the MXT with the 12" Concentric coil will match or even beat a TDI when it comes to all out depth, I actually saw someone do that with one of the first MXT's when I gave them a 12" coil to try out and he only had the Gain up around 6 to 7, The only honest to God reason to buy a PI machine is if you have bad ground to detect, Again this is not directed at anyone but these are a couple of examples of what I found by owning and buying the above machines, Take a PI and a VLF in to hot prospecting gold baring land and a PI will whoop the VLF all day long. Don't be down about your air test results because in bad ground or at the beach a PI will do those depths all day long where as a VLF will be lucky to get 50% of those depths but on a good day or the right soil conditions a VLF will surprize a person, As to which is better or deeper is more of a case of matching the machine to the soil conditions. J.

When you air test a PI you can listen to it's maximum distance where it goes woo woo or just listen for a slight break in the threshold, In quiet non junky sites you can use the break in threshold way of detecting to gain maximum depth out of the machine, I also use this method when using my VLF because it can change depth from inches to Feet, IE where a coin might bleep at 14/15 inches with some coins using just the threshold can add between 4 to 10" depending on the coil being used, of coarse in ground depths would be as little as 20 to 25% of those figures but it is just another way of detecting and requires a massive load of concentration.

Well Jim It just about drove me nutz, because every thing people said did not happen the way they said, And I found it to be better with the GB On, It worked like a charm but just opposite the my TDI Pro, Must admit I do love being able to select low or high conductors, Not quite discrimination but it sure cuts down in the junk, Great machines they just need hotter coils is all.

It's Great to see this happen because just when you think things are drying up and boom and it restores the faith again and give us a reason to keep going, big congrats to the finder, well done Sir who ever you are.

Just poking around on Whites website and someone hit it big with a 67.4 gram 2.166 ozt Nugget with an old XLT. https://www.whiteselectronics.com/find/monster-nugget/

Well Steve I did wonder if it was working properly because I never got the results others got out of their SL's, and not once did I ever get it to see bits weighing 0.17grams or less which diggerbobs SL clearly did, So I don't have the answers as to what or why because mine could not do those things, On big Items it was extremely deep but for what I wanted it for a VLF was the better option, I wish I had sent it back for a tune up but life took over time slipped by so I gave up and forgot about it as my health declined, Still they are a very good machine and for certain tasks and they are a great all rounder.

I find that very few manuals explain exactly what the numbers mean in real world terms, The system I use tells me all I need to know at a push of a button as it updates the ground Phase figures, Between 50 and 99 tells me the ground is high in Iron and the higher the number the higher the level of Iron and from 50 down to 0 tells me the higher the Alkali levels are, and the lower the number the worse the Alkali levels are, Real world usage of these numbers are only a guide and all they tell me is how my depth is going to be effected and whether I need to try and match my choice of coil to suit the ground conditions, Large or Small, DD or Concentric, And that is all that is needed to be able to run a machine at it's optimal setting. Other uses of these figures are more directed at prospecting than detecting, Most of us never even knew about Fe numbers until the F75 came out and with it's combo of Bars and Fe numbers it is still a bit OTT and I think the detector companies don't go too deep in to the why's and wherefores about them in the manuals is because Once things start to get a bit technical then that would involve a whole manual all of it's own and the marketing world knows as consumers we are terrible at reading manuals at the best of times, Even more so being detectorists because all we want to do is get out there and get digging, Having multiple readings of bars and numbers is just another thing to pull us up and give us something else to work out which eats away at detecting time, These things are great for the Tech minded folks but the person who wants to beep and dig won't even use this feature. A simple way would be to just have 4/5 Icons saying AL = Alkali Low, AH =Alkali High and a "Normal" mid reading and then IL = Iron Low and IH = Iron High, Other than that do we really need to know much more, ?.

I wrote that " How Too" using different batteries and a couple of things I noticed about both the TDI Pro and the TDI SL and that was feeding the SL Over 12v made signals a slightly harder response, 2 In Air Tests It was hard to tell the difference between the two, 3 For some reason my SL saw things deeper in Air Tests with the GB On, which I decided was a good thing if a person was operating it in bad ground 4 The smoothing effect shown it that beach video with the TDI Pro with the GB OFF my SL would do it with the GB ON, 5 The Battery Pack I made was good and gave me over 12v when using 9 X Duracell AA's gave me 14.49v and using Energizer Lithium gave me 16.4 because they have a much higher surface charge, But using 8 of the Energizer Lithium would give me 14.64v and a run time of over 20 hours, 6 Using the factory NiMh 2200mah battery pack would run the SL for around 4h 20mins, Using my 9 cell pack with NiMh AA's would run the SL for just over 5 and a half hours,

I believe that Dave J or Carl would have made such a machine if it were at all possible, Between them over the years they have given us the best machines on the market, They are the two people that I have the most faith in so maybe one day they might surprize us all.

Excellent explanation Steve, way back when I use to believe that a GB system would make it all go away thinking that my detector was putting all that voltage in to the ground and no signals meant nothing was left behind, Alas a PI bought me down the earth with a thump which lead to me loosing faith in my VLF's which made me worry enough to take time out for a few months, Learning to except a VLF for what it is Is half of the battle and getting past that is the road to success, John.

Even after all these years I still wonder why mineralization has such a devastating effect on how a detector performs and I understand what the GB is doing but even with a perfect GB the mineralization still takes it's toll.