TDI Test

[Geo]

Hi.
Yesterday i went for test with TDI and 12" coil at a place where there are a lot of stones and ceramics from an very very old village that now don't exist. I must say that i had detected this place a lot of times before, and last times without any result.....
I adjusted the TDI at 10us, GB=on, GB at 9 (at this place it made ground balace), all conductivity and sensitivity about max.....(not erratic signals). I went up of the ceramics without any any problem. I found only some rust iron objects at distance from5 to 20cm. Nothing deeper.
I wanted more depth.....
But the basic problem is that with this adjustment, detector must give a high tone at rust iron objects and NOT low that gave to me. So today i made a some tests at Lab and i attach here.
If you will look carefully, you will see that there are some holes....
I am interesting about gold, silver and copper, and to reject the rust iron and the ceramics. There is not a adjust for it with a "good" depth. So i must make some adjustments so to see what is down the earth.
On top of the table you will see the detecting depth without ground balance. Sensitivity is set a little low because inside the lab i had erratic signals.

Regards

[Geo]

I attach again the table at jpg format so to be easy to everyone to check it.
What i see in at this table??? That the best adjustment to detect gold, iron and coper is the 17.5us with GB at 8...11. Disadvadage is that at this area it detect with the same low tone the iron. After it if we took a signal we can adjust the GB at 6 and delay the same (17.5us). Now if the detector will give a hight tone then it is iron...
Normally we can adjust at 10us and let the GB at 8...11, it will beep with hight tone at iron, but i don't know WHY at field i had a low tone with this adjustment.

Regards

[Geo]

Error correction...
I write for delay 30us. the right is 25us.

[Max]

I attach again the table at jpg format so to be easy to everyone to check it.
What i see in at this table??? That the best adjustment to detect gold, iron and coper is the 17.5us with GB at 8...11. Disadvadage is that at this area it detect with the same low tone the iron. After it if we took a signal we can adjust the GB at 6 and delay the same (17.5us). Now if the detector will give a hight tone then it is iron...
Normally we can adjust at 10us and let the GB at 8...11, it will beep with hight tone at iron, but i don't know WHY at field i had a low tone with this adjustment.

Regards

Hi,
don't know about TDI but seems to me you get that wrong tone cause of near to extreme GB setting.

You know why... other PIs are similar stuff: when you are in an ancient site there are bricks and ceramics all over the place... at any depth etc

then if there's GB you use it to save nervs and digging holes for these fragments of fired clay... OK

But ? You lose depth and you lose any (if there is) good discrimination.

I think TDI is not different about that, cause you put GB at 9 and lose disc, at least seems so.

So rusty iron (e.g. piece of fence or wire) sound like good target of gold or silver...

what to say ? TDI isn't good... ? No.

TDI is PI and PI is not good AT THESE SITES.

Just that.

If you use on beach you'll find very different... you need less GB and can go at lower delay, get gold and good stuff and reject by tone (not always but most of the times) rusty iron...

Is all like that: PIs are good in some scenario and bad at other.

In places with fired stuff and hot rocks is much better having VLFs.

The advantage of PIs is depth: when you lose it you lose anything !

The advantage of VLFs is geb and disc... if you have it you gain everything.

In such places PIs lose any actractive , and VLFs gain all, even if VLFs depth is not like PI in air.

On such soil performance of PIs and VLFs are similar at depth, but VLFs offer you much better geb and disc.

My advice is using PIs at beach and on "easy soil", VLFs elesewhere and as general purpose.

Kind regards,
Max

[Geo]

Hi Max.
Maybe GB at 9 or 10 to create this problem but i believe that at high numbers i have less Ground balance..... When i balanced the ground .... it was near 8...9 , so and the 10 or 11 is near.
Generally ... i agree with you but there is a problem...
VLF can't detect down the old ceramics. Before 4 days i went for treasure hunting with my Superscan. Another boy had a Explorer SE. It detected a coin at 40cm on air very easy... When i put the coin down a ceramic, it detected it at about 15cm...., so we found Nothing
PI if detect it at 30cm with GB or 35.. 40 without GB, it will detect the same distance and at the case where the coin is down the ceramic...
With general words when we looking for something at a ancient site it is better to use a PI detector. Maybe it was bad choise to use the GB, but what to do with ceramics.....
The only sure is that TDI needs more much time to experiment with it, so to understand it well

Regards