Findmall.com
 
 






Whites TDI Classroom


Welcome! Log In Register
Will the TDI be good for Roman bronze coins?
Posted by: LOTR
Date: October 10, 2011 09:44AM
Hello friends!

I've been using several VLF detectors but it appears that the depth is crucial for the Roman coins on my fields, which are my primary targets.

It'll be very useful for me( I believe for many other members too) to get opinion from experienced users about TDI on Roman sites, which are quite iron-contaminated areas.I wonder if the TDI will be fine for detecting bronze Roman coins( no doubt about silver ) ?
I reckon that the bronze is not as high conductive as silver and gold, but I need to know if the TDI will sound the same ( with high pitch tone), or at least similarly as for high conductive metals?
Any guidance or the maximum depth for small( 10-15 mm), medium (15-25 mm ) or large bronze coins(over 25 mm) will be additional help for a potential buyer of a TDI. Suggestions about additional deep coils are also welcome.

Thanks in advance and HH

Re: Will the TDI be good for Roman bronze coins?
Posted by: Eric Foster
Date: October 14, 2011 12:44PM
The lack of replies is likely because this is a new area for TDI users, most of whom are in the USA or Australia. It is a certainty that the Romans never reached the American shores, in fact there is scant evidence that they even ventured to the east coast of Ireland. There are only a handful of TDI users in England and I do not know of anyone who has used a TDI for this purpose. That is not to say that it wouldn't excell at finding such coins, but one would need to run some tests to see what the responses are. Sad to say that I do not have any Roman coins now, even though in the early days pulse induction detectors were used to great effect on archaelogical sites to find ancient coins. Many Roman sites have strongly mineralised ground, so the GB feature would be very useful. Also such sites are often littered with small iron i.e. sandal nails, which although ancient, are of little interest. The response from bronze coins would depend on their diameter and thickness. Larger bronze coins would almost certainly give a low tone, while the small coins would likely give a high. Silver usually gives a low tone unless very thin and small. Gold depends very much on the purity, as well as size and thickness. I searched a Roman site (with full permission) many years ago and was frustrated by all the nails, as the straight PI I was using had no discrimination. However, a larger than normal signal got my attention, and it turned out to be a nice iron Roman door key. I suspect that sandal nails, being very small would give high tones, so by switching to the high conductor mode would bring in the larger bronze and most silver coins, as well as eliminating any ground response. Why not buy a few coins on ebay and see if a Whites dealer has a TDI that you could test them on?

Eric.

Re: Will the TDI be good for Roman bronze coins?
Posted by: dbsmokey
Date: October 14, 2011 03:55PM
I have a tdi and a handful of Roman coins I purchased on eBay. I will try to test them this week to see what sort of signals result(high/low).



IDX Pro, MX5, BHID, M6, MXT Pro, Surf PI, TDI, CZ-5, CZ-20



Edited 1 time(s). Last edit at 10/14/2011 04:07PM by dbsmokey.

Re: Will the TDI be good for Roman bronze coins?
Posted by: Terrytorment
Date: October 15, 2011 12:39AM
Yes the TDI will find the small Roman bronzes in mineralised ground, All of a batch of 47 I have tested you will get with the machine set to low conductors as set for standard nugget hunting.
A lot of small hammered silver coins can come in at this range also.
The only issue is a lot of small Iron must be dug and can delay your search time and you will have to go over the same ground again in high conductor setting for any targets ring pull and above conductivity readings.

There is an alternative you could try....

I have yet to try a small DD coil on the TDI but I have a standard Minelab GPX5000 DD coil which works well on mineralised pasture using this method.

So, the theory is, stick a small DD coil on and search in normal pulse mode (not GB mode). If you can work your site this way (perhaps with lower sensitivity settings) discrimination on small iron is not such an issue, signals are smoother and you won't hide as many non ferrous targets behind iron. I would advise you practice this method on the beach wet sand areas to get a feel for different target behavour so you can suss out iron signals from good non ferrous ones.

I've added a pic of some Roman coins tested, found recently with another detector, All but the largest coin read as low conductor.



Good hunting

Terry.



Edited 1 time(s). Last edit at 10/15/2011 01:02AM by Terrytorment.




Re: Will the TDI be good for Roman bronze coins?
Posted by: LOTR
Date: October 16, 2011 07:13AM
Thank you friends for your time given to this topic. I have already found dozens of Roman coins with my VLF detectors, mostly the coins were on depth between 10-20 cm( 4-8 inches), and mostly on a meadow and cultivating fields. The problem I am sometimes facing with is that, in one particular field where I found most of the coins, the ground is so mineralized and so condensed( compressed) that my VLF machine barely detects a large bronze coin (20 + mm diameter) on 5 inches on the dry soil. Yesterday I was beeping around,dug out 2 coins and 2 beautiful large finger rings(one of them was the deepest target, over 8 inches), but the soil was very wet due to heavy rains in past several days.I believe that you also noticed increased detector's depth on a wet soil.
I don't own a TDI so I can't run any test, but I would highly appreciate everybody's efforts in presenting one on this topic.
What I also need to know is whether the TDI will be deeper than common VLF detectors on large bronze and silver( over 20mm) and discriminating small iron at the same time? Also, I would like to know what was your deepest findings with TDI equipped with 12'' coil ? Just as a comparison, my VLF brand machine with 12x15'' butterfly coil detected a large Roman bread frying-pan (iron, diameter around 11+ inches) on 80+ cm with a quite strong audio signal.
Greetings and happy hunting :)

avatar
Re: Will the TDI be good for Roman bronze coins?
Posted by: woodchiphustler
Date: November 26, 2011 07:57PM
Depends on the ground. What is the number you achieve ground balance? You will loose depth on all high conductive coins with normal thickness. The lower the GB the more depth is lost. Good news is small low conductive coins such as hammered will ring thru loud and clear. You can manipulate the GB control to a point were some small ferrous targets will shift tones.



George Tex Kinsey
The Original Buttondigger since 1969
Still on the "right side of the grass"
A Findmall fan and supporter.

Re: Will the TDI be good for Roman bronze coins?
Posted by: filternozzle
Date: December 03, 2011 11:06AM
Quote
LOTR
Thank you friends for your time given to this topic. I have already found dozens of Roman coins with my VLF detectors, mostly the coins were on depth between 10-20 cm( 4-8 inches), and mostly on a meadow and cultivating fields. The problem I am sometimes facing with is that, in one particular field where I found most of the coins, the ground is so mineralized and so condensed( compressed) that my VLF machine barely detects a large bronze coin (20 + mm diameter) on 5 inches on the dry soil. Yesterday I was beeping around,dug out 2 coins and 2 beautiful large finger rings(one of them was the deepest target, over 8 inches), but the soil was very wet due to heavy rains in past several days.I believe that you also noticed increased detector's depth on a wet soil.
I don't own a TDI so I can't run any test, but I would highly appreciate everybody's efforts in presenting one on this topic.
What I also need to know is whether the TDI will be deeper than common VLF detectors on large bronze and silver( over 20mm) and discriminating small iron at the same time? Also, I would like to know what was your deepest findings with TDI equipped with 12'' coil ? Just as a comparison, my VLF brand machine with 12x15'' butterfly coil detected a large Roman bread frying-pan (iron, diameter around 11+ inches) on 80+ cm with a quite strong audio signal.
Greetings and happy hunting :)

Hi LOTR,

Did you manage to get the answers to your questions re TDI/VLF? I am interested in this information myself. Just posted a message asking if there is anyone within the UK working farmland with the TDI.
Richard

Re: Will the TDI be good for Roman bronze coins?
Posted by: LOTR
Date: December 03, 2011 04:54PM
well, the answers/tips given above are quite useful but i think that the best way is to test tdi pro/sl on the roman field and get the right overview of how it performs.so far no perfect detector, only the one that fits to your needs :)

cheers

Re: Will the TDI be good for Roman bronze coins?
Posted by: filternozzle
Date: December 04, 2011 02:43AM
Quote
LOTR
What I also need to know is whether the TDI will be deeper than common VLF detectors on large bronze and silver( over 20mm) and discriminating small iron at the same time?

Hi LOTR,

Am I right in assuming you did not getting any feedback on this particular question?


Re: Will the TDI be good for Roman bronze coins?
Posted by: LOTR
Date: November 07, 2015 04:15AM
Hello diggers :)
It was about time for me to resurrect my hobby. After dealing with more pressing matters I finally ordered new Whites TDI SL with 12'' DF coil, standard one.
In a week or two you can expect some tests and answers on the questions I made above.I just hope the sunny weather over here remains the same for a little longer.
Cheers :)

Re: Will the TDI be good for Roman bronze coins?
Posted by: togg77
Date: November 10, 2015 04:19PM
Interesting--we await your report.

avatar
Re: Will the TDI be good for Roman bronze coins?
Posted by: Mega
Date: November 21, 2015 11:28AM
I have a TDI sl version coming,this has the stock 12'' coil as well as the 7.5'' coil as well,mine will be used mainly for one specific site that has produced nothing but 1000s of roman coins over the years,what makes this roman site unusual is the fact that the ground conditions are possibly one of the hardest dues to high ground mineralization,the nearest that i can describe it its like wet beach detecting but 80 miles inland and mainly only 2 fields,hence the need for a Pulse machine.

You can use a VLF machine but boy is it hard work,but if you can get a machine like the TDI then you stand a very good chance of finding no end of roman bronze and silver unit and also the odd possibility of the odd gold solidus.

My way of thinking is that by using the TDI sl with the 7.5'' coil that could end up being a winning combination on this roman site,even the 12'' coil stand a tremendous chance of hitting deeper targets that have not been touched on this site,it was used for 400 years by the romans and hence the massive amount of coins in this location.

When my TDI sl arrives and we can get back on site again i will update on how we get on,by using the right tool for the job i feel it could still end up being a very productive site.

Currently looking for a slightly larger coil for possibly deeper targets on another site,but that another story.



Full Deus---DFX---T2---IDX Pro---Whites TDI Pro---Nexus SE dual 9'' coil the 'badboy'---Fisher TW-5 twin box---Trident 11 Extreme---Crossbow PI---Mirage PI---Silver Sabre11---Laser B3---Arado120b--- and a few others.

Re: Will the TDI be good for Roman bronze coins?
Posted by: LOTR
Date: November 21, 2015 01:22PM
Hey Mega@
I picked up my TDI SL yesterday and just tested indoors if it works, and it does :) Today and tomorrow I am working (damn 12 hours shifts) so hopefully I'll go out on Monday for a field test, just praying for no rain. I got 12'' coil, and I bought TDI just for a single , remote forest ruins. I already found dozens of Roman and Byzantine bronze coins there and one and the only gold coin so far ,a 14 mm (tremisis) Byzantine coin with my VLF detector. The soil is not soil, it is more like very very much mineralized rocks, in some areas I had to run my GB on XP goldmaxx over 1 o'clock, and normal DB is 10-11 o'clock, so I reduced depth dramatically. I hope we keep this topic updated and alive with some useful tips,interesting videos and cool pics :)

TDI for Roman coins? Excellent !!!
Posted by: LOTR
Date: November 24, 2015 03:43AM
Hello beepers :)

Yesterday I did a short Whites TDI SL with 12'' coil depth/separation test in my backyard using different coins:

22 mm silver Serbian coin
32 mm silver Ottoman( Turkish) coin
30 mm copper Ottoman coin
22 mm bronze Roman coin
30 mm bronze Byzantine coin

All coins are in high conductivity range, at the same time TDI ignored square old nail 15 mm diameter and small lead objects of different shapes and sizes up to 2 cm. And that is perfect for the fields i am searching on, using high conductivity mode. I had no any large /thick gold coin or medallion to test so i have no clue in what conductivity range it belongs, i guess it is high but any hint will be appreciated.
Settings used for test:
Pulse delay 10 ms
GB 8
Freq at 12 o'clock
Threshold by choice
Gain at from 7 to 9

Depth results :
22 mm silver Serbian coin detected at 30 cm
30 mm copper Ottoman coin at 30 cm
32 mm silver Ottoman coin at 35 cm
30 mm bronze Byzantine coin at 30 cm
22 mm bronze Roman coin at 27 cm

Also, I did a test using a stone 20 cm thick and two bricks placed one over another, each 5 cm thick.Did GB over it, placed first 22 mm silver coin and after 32 mm silver coin beneath: No signal at all at any gain value, when i removed one brick I achieved even better depth results than in soil, Both coins were detected with nice repeatable sound .So, quite impressive it easily penetrates 25 cm of solid rock/stone. I believe this is not the best TDI can do, it just takes time to master it.

Recovery speed test :
Iron square nail at depth 15 cm in first hole, silver coin 22m at 25 cm in second hole, lead ball at 15 cm in third hole. Distance between each hole 5 cm. Coin detected with nice repeatable signal. I only did with this coin , and this depth since the rain started so i had to quit the test.I test it with same settings as above only in high conductivity mode so i am not sure it this is valid? Any comment will be useful.

First impression after test: This is an awesome detector for my needs with excellent depth. I am total newbie with it and I am sure this machine still has aces in sleeves to show off :)
HH

avatar
Re: Will the TDI be good for Roman bronze coins?
Posted by: Mega
Date: November 24, 2015 06:21AM
@ LOTR,those are some very encouraging figures that you have provided,mine will be here before the weekend,and will be used on very similar sites as yourself and with the same coinage as well,thats some very good news about the large nails that it rejected as one of my sites is littered with roman hob nails from the hobnail boots that they wore.

I have the 12'' stock coil,7.5'' coil and also will be ordering a larger 14'' coil from Razorback just to gain some additional depth on a possible hoard site that i have access to,my way of thinking is that with these 3 coils it should cover me for most of my site needs.

Thanks for taking the time to give some feedback as those coins sizes are the same as on my roman site.

HH



Full Deus---DFX---T2---IDX Pro---Whites TDI Pro---Nexus SE dual 9'' coil the 'badboy'---Fisher TW-5 twin box---Trident 11 Extreme---Crossbow PI---Mirage PI---Silver Sabre11---Laser B3---Arado120b--- and a few others.

Sorry, only registered users may post in this forum.

Click here to login